The Hammer Down Diesel Store


Instructions / Trouble Shooting

Fuel system : A new lift pump will not fix either an air in fuel or drain back problem or a weak/faulty overflow valve. Even new Tork Tech overflow valves tend to be a problem !! Don’t believe this, look it up on net.

So, please don’t waste my time if you refuse to fix an existing problem or one the is caused by disturbing the old fuel system. I’ve heard them all & every single time, it has nothing to do with the new lift pump.

Common problem on customers end is : faulty pressure gauge & system, old or improper fuel lines, cracked tank pu, air leaking into hoses/fittings, or fuel heater. Also sludge/debris in fuel system are just a few of the reasons your having problems with fuel pressure/flow.

Bypass the whole downstream section of your fuel system before lift pump & install a short 3′ section of new fuel line & stick pu end in a bucket of clean diesel. Then prime lift pump & try starting engine. 9 out of 10 times problem solved. Your downstream fuel system needs to be replaced.

So again, please don’t waste my time.

Oil Pump Install

Make sure to torque up to 18ftlbs in a cross pattern so it sits parallel to the block when done.

As per the Cummins manual…when the pump is correctly installed, the flange on the pump will not touch the cylinder block“.

And YES it is a genuine Cummins oil pump…Cummins has been making their oil pumps in their factory in China for years now.

2nd Gen Dodge Diesel Performance

AFC (aneroid fuel control):

Starwheel and Housing

Basics – Housing adjustment is a gross adjustment and starwheel is a fine adjustment. Moving the housing forward towards the radiator will allow more bottom end fuel (little to no load fuel) and back less. Adjust this 1st and get a happy medium for your setup. Then fine tune it with starwheel for final tip in fuel.

To adjust starwheel, use an 8mm allen wrench to take the plug out of the top of the AFC housing (near rear of inj pump). Then you can see the gear (starwheel) in there and all you do is turn it. A flathead screwdriver works best. If the gear is pushed towards the engine (moving up towards the radiator), the turbo boost will take less pressure to overcome the spring and you will get more fuel/smoke when you initial accelerate with low or no boost built. If you rotate the gear towards the drivers fender (moving towards the cab), it will take more boost pressure to move the AFC foot, hence less fuel tip in and will prevent less smoke on accelerating with low or no boost built. 

By tweaking the AFC to just the right spot, you can get a good amount of spool up with a small amount of smoke.Adjusting for best acceleration = very little smoke (just a haze) out the tail pipe at heavy acceleration.

AFC Smoke Screw:

 On the back of the AFC housing is a small cover, that covers a small allen set screw, with lock nut. The cover for the set screw has an anti-tamper screw but it can be taken off with pliers or a very small flat head screw driver. You can reuse it. 

The set screw lock nut is 10mm and must be loosened before adjusting the set screw. This set screw determines where the AFC arm starts from when you have no boost at idle and/or little to no boost at low load. Since the AFC arm determines how much fuel the engine sees pre-boost, adjusting this will let it have more or less fuel before any boost is built. It does not determine how much boost it takes to move the AFC arm over, but rather allows you to set where the AFC arm starts from. Turning the screw in towards the radiator will increase fuel and out towards firewall will lesson fuel. Adjust set screw to your liking. Adjust and take truck for a test drive. Adjust more and test til your happy. You can adjust to lesson fuel idle haze with this smoke screw too !!! Make sure you tighten that 10mm nut down before putting the small cover back on when your happy and done.

Fuel Plate/Camplate:

 As always its recommended to have a boost and pyrometer gauge to monitor what your engine is doing at all times. Do not run your engine at more than 1200 degs, pre-turbo measurement for longer than 15 sec’s.

The fuel plate is the limiting factor concerning fuel ramp rate and full fueling. It limits the fueling arm and is a way to keep your engine at a certain power level. The fueling arm (also known as the governor arm) moves forward and up as RPM goes up, so the higher up in the RPM you are, the higher up on the fuel plate it will ride. The farther the fuel plate is towards the radiator, the more fuel you will be able to pump, which will increase the power as long as you have the air to burn the extra fuel.

 The fueling arm is connected to the rack and the farther over it goes forward, the more fuel it will flow. It is important to remember that the arm only touches the fuel plate, when you have given it enough throttle and boost overcomes the AFC arm, which moves forward out of the way, allowing the fueling arm to contact the fuel plate. Under light throttle/low boost, it never touches the fuel plate, just the AFC arm.

 There are many pre-designed contours to give different fueling characteristics. They can be made to have high power at different RPM’s, have defueling contours to control EGT’s, and many other things.

Fine tuning can be done easily by loosening the fuel plate screws and sliding it one way or the other. Towards the fueling arm (away from radiator) will cause it to fuel less, and vice versa. Going all the way towards the radiator is called full forward.

 Adjusting the stock fuel plate is basically a waste of time, unless you are willing to adjust the governor arm at the very back of the pump, which is hard to do and get it right. Don’t get me wrong, many have done it but it takes a lot of trial and error and the gains are low due to the poor fuel profile of the stock plates. Much easier to install a TST fuel plate like my favourite, the #10 plate which requires no governor lever adjustment in any year p7100. The profile is a good overall plate for any p7100. A good balance of power and user friendly. Place the #10 plate were it works best for you and forget about it !!! Fuel plates such as the #6 fuel harder than a #10 but it requires a governor lever adjustment to run right. 

With this all said, running a fuel plate all the way forward doesn’t always make more power. Too much fuel and not enough air will result in higher egt’s, more smoke and less power than you can make with less fuel and/or more air. 

Rack Plug:

After you’ve modified the Fuel Plate and AFC, you may want to get a 2095 Rack Plug aka Mack Plug. The 2095 plug has a 2mm deeper well than the std 2000 plug, allowing the rack to travel further increasing power. You can get one for about $15. Pump must be loosened from gear casing and engine brackets to install this plug though. It will provide a greater increase in horsepower if you already have more power to begin with. 500hp motors will gain about 25hp, while 300hp motors will gain only 10hp. Again, this only works if you have an aggressive plate and a modified AFC arm.


One last mod to the pump is timing. Stock timing is 12.5degs in 94-95 pumps and 13.5degs in 96-98’s. You can adjust your pump safely to 16degs with your healthy stock head gasket and bolts. This is highly recommended for even a stock engine. You could go up to 19° with a o-ringed head, aftermarket head studs and 155deg spray pattern inj’s. As much as 23deg’s timing with 145deg spray pattern inj’s. Advancing the timing allows better economy and more power, as well as where in the RPM range you get the most power at. Note, the higher timing you run, the harder your start up will be, specially in the cold and the more bottom end you will lose. So there is a balance there, that will suit you with trial and error. 

New pump crush washer is highly recommended and pump nut torqued to 165ft/lbs.

Governor Springs & Install:

The stock governor springs allows the engine to fuel to 2600 RPM, but they start to pull back fuel at 2300 RPM. There are performance 3K, 4K, and even 5K Governor Spring Kits for sale. A 3K consists of 2 new bases and 4 springs and will fuel to 3000 RPM and start pulling back fuel at 2750 RPM . A 4K consists of 2 new bases and 6 springs and will fuel to 4000 RPM and start pulling back fuel at 3600 RPM depending on install height. You can make a 4K GSK into a 3K if don’t have the valve springs yet, by leaving the smallest springs out on install. If you install the HD valve springs down the road, then you can simply install the smallest springs into your pump to make it into a 4K. Governor spring kits add approx. 15hp and a much more broader fuel/rpm curve.

DieselTuff doesn’t suggest running the 5K GSK’s as they are notoriously finicky and are really only for pullers and require extreme modifications to the engine to not be damaged. Warning….If you run the engine at 3200 RPM or higher, without a complete set of 12 HD 60 lb valve springs, you run the risk of floating your valves and causing engine damage !!!

Over all the years of helping customers at PDR, governor springs installs tend to be the hardest for people to do. It really isn’t hard at all, if you can read plain english and pay attention to the install instructions !!! When it says “Measure carefully before removing anything” and “Do not remove the largest stock springs in your pump”…that means measure 2 or more times and leave the largest stock spring in your pump…don’t remove that spring for any reason, period (the largest stock spring on both sides of the governor assembly).

Here’s my simple Governor Install Instructions:

Removal :

Either take AFC housing off and remove fuel plate method or go in through the round side port of pump method. Either one works and is about the same amount of work, it’s up to you. Don’t ask which one should I do. lol

Which ever method you decide to do for the install, have a clear view to the governor rotating assembly by which ever method your using. Now rotate your engine over by hand (22mm on alternator method works great) or better yet, have someone rotate it over for you, as you watch the governor assembly.
 Once you have one side of the governor springs & retainer lined up, for a unrestricted removal path. Measure using a vernier calliper, from the top of the treaded retainer stud, to the top of the retainer nut (not into the grove of the retainer nut) it should read approx.  .050″ (give or take .010″) if no one has messed around in there prior. What ever the measurement is, double or triple check the measurement again. Write it down. Now using a med size screw driver, start unscrewing the retainer nut off of the stud (pay attention to how it feels screwing out….you will feel the nut has a cam profile to it, so count the clicks/bumps while removing it, until you can’t feel the clicks anymore).
 Once it starts to get real loose, use a pencil magnet to unscrew it the rest of the way. What ever you do, make sure you never drop anything into the pump !!! Damage will incur if if can’t fish it out and you rotate the engine over !!! Remove spring retainer next with magnet.

Now using your pencil magnet, remove all the stock springs, other than the largest spring (re-read above for those that have a short attention span), also the 2 piece stock spring base (base may have shims in-between the 2 pieces) and any shims under base. If there is any shims still in your pump but you can’t pull them out without taking out the largest stock spring….leave them there !!!! This/these shims are your idle shim(s). Removal of these shims will result in a piss poor idling pump, no matter how many times you try adjusting your pre-load nuts of governor springs. 

Install :

Now with magnet, install the new spring base that came with your kit down onto the threaded stud, with largest diameter surface down. Install half of the new springs from your kit (again, leave out the smallest spring in kit if you bought a 4K and want to run the 3000gsk or install it, if you have or are going to install 12 HD valve springs on cyl head). Now line up and install the spring retainer (take note..the retainer has a slotted hole that slips onto the threaded stud). Now thread on the retainer nut and once you feel the 1st click/bump, screw down how ever many clicks/bumps that you counted originally removing it (each click is approx. .017″). You should now be close to the original measurement before removal. Measure it like you did before removal and re-measure it again to be accurate. Do not turn nut and leave it at a different setting other than at the bottom of a click/bump, even if your measurement is slightly different then your original measurement !!!!

 If you are within .009″ of your original pre-removal measurement, your good to go for that side of governor. If you are out more than .009″ then turn retainer nut either way one click/bump to achieve closest to original measurement. 

Now rotate engine over by hand again, until the other side of governor lines up for removal and install. Repeat above instructions and your done. If for any reason, your idle is different than it originally was, double check all your measurements and procedures. Done correctly, your idle should be the same and engine should be running as smooth as before. Enjoy your new 15hp and more useable rpm’s.

Delivery Valves, Inj’s, Lift Pumps & Install Instructions:

Delivery Valves meter how much fuel flows out of the injection pump, per stroke and also dampen the fuel pulse generated. Stock DV’s on 1994-95 auto’s (160hp) are 131’s and std’s (175hp). Stock on 96-98 auto’s (180hp) and std’s (215hp) are 181’s. There are also other DV’s from industrial applications, such as 022’s, 024’s,191’s 035 etc. We have been making full cuts, also known as laser cuts for many years. I’ve also tried mixing the stock 131 & 181 to make hybrids, although the gains were too small to be worth the hassle. DieselTuff also innovated their own style of DV, known as Taper cuts by machining a tapered shoulder in the stock 131’s or 181’s. 

Fuel Flow – low to large

131’s = Too small to run bigger inj’s than 40hp

181’s = Can run bigger inj’s to 140hp in none benched pump but too small for a maxed out benched pump and big inj’s

024’s = decent bottom, mid and ok top, can run bigger inj’s for street use

035’s = 7mm best all around performance DV on the market. Flow more than 024’s but at a higher pressure so better performance.

022’s = lots of bottom end fuel, smoke, great mid and top end. Not recommended for street due to very smoky/heat

Taper cuts = shoulder allows almost stock flow at low fuel demand, low smoke, great spool up on excel due to progressive flow and large fuel flow at high fuel demand. Best of both worlds for street.

Full/Laser cuts = are machined down so they don’t have shoulder material like the other ones, so they fuel instantly unlike most other DV’s. They fuel so hard, that we don’t recommend them for the street at all, as they smoke like crazy and run crazy hot, not to mention the loss in fuel economy. 

Removal & Install:

Remove air intake horn bolts using 10mm socket. Carefully remove air horn (if done slowly, the gasket(s) on heater grid will be intact and can be re-used. Remove inj lines, using 10mm socket & 19mm wrench. Use a dv socket (special socket for dv holder) and loosen the dv holders counter clockwise to finger loose only !!! This takes some effort, as they are torqued on to 89 ft/lbs. Before removing holders one by one, use a rag or compressed air to remove any dirt/oil around base and threads. Be careful with the green or black dust o-ring, as you can re-use them (have done many of dv changes without the need to replace these o-rings). It is a good idea at this time to lay some rags in-between the inj pump and cyl head to help cover the gap so as not to drop anything between the two. Now carefully unscrew dv holder the rest of the way by hand and carefully lift up the dv holder slowly, while turning the dv holder over/upside down at the same time (this will stop the little spring and dv plunger/shims from falling out/over). Place dv holder and plunger in/on a safe clean area. Lay them out in their order. Now use a pencil magnet to remove the dv pintle and dv base from inj pump. If replacing stock dv’s with dv’s with the more sealing base surface, such as the 181 style base, pull out any metal shims that may or may not have been under the stock dv bases. If none were there to begin with, that’s fine. 

Now install your new or modified dv’s in the reverse order they came apart. Make sure you line up the small spring with plunger/shims onto the top hat section of the dv pintle (has the #’s such as 131, 181 stamped onto top of pintle) while you place dv holder and screw back on by hand. Tighten dv holders to 89 ft/lbs. Re-install fuel lines just snug with wrench, all but 3 which you will want to leave the nuts finger loose at injectors (this will help bleed air from lines while cranking). and then intake horn. Crank engine for 5 sec’s. Stop. Check to see if fuel has come out of the 3 inj line nuts. If so, tighten and engine will fire with a little more cranking. Once engine fires up, check for leaks. Engine should idle the same as before. If good, take truck for a test ride. 


Stock 94-95 autos are 160hp. 94-95 manuals are 175hp. 96-98 autos are 180hp. 96-98 manuals are 215hp. There are also marine 300, 330, and 370 hp injectors from Bosch but they have the 155deg spray pattern but are now considered old school inj’s now unless you are running the wide/big bowl pistons. Running the marine inj’s won’t hurt your motor, but they haze at idle, smoke more, and run warmer than comparable size 145-148 deg inj’s. There are much better inj’s available now. DieselTuff builds most of the 12v inj’s on the site in house.

Removal & Install:

Remove air intake horn bolts using 10mm socket. Carefully remove air horn (if done slowly, the gasket(s) on heater grid will be intact and can be re-used. Remove inj lines, using 10mm socket & 19mm wrench. Remove return line banjo bolts and copper washers with 10mm wrench. Use a 15/16 or 24mm deep socket to loosen inj hold down nut. Use a inj puller tool or carefully clamp on a set of vice grips to the flat shoulders of the inj’s (not on the flat banjo bolt hole) and use a pry bar to pop up the inj’s one by one. Make sure the old copper sealing washers come out on inj’s or you must pull out of inj bore holes in head. Blow out inj bore holes and make sure everything is clean. You can spray brake cleaner in bore if you have.

Now install new copper washers on new or rebuilt inj’s. You can use vaseline to help hold washer to inj body. DieselTuff likes to use the thinest washers to get more nozzle penetration. This helps keep the fuel spray deeper in the piston bowl with higher tiny pump timing. Install inj’s into inj head bore while lining up ball of inj to grove in head. Screw down inj hold down nut to 44ft/lbs. Re-install banjo return line washers and bolts to 10ft/lbs. Re-install fuel lines just snug with wrench, all but 3 which you will want to leave the nuts finger loose at injectors (this will help bleed air from lines while cranking). and then intake horn. Crank engine for 5 sec’s. Stop. Check to see if fuel has come out of the 3 inj line nuts. If so, tighten and engine will fire with a little more cranking. Once engine fires up, check for leaks. Engine should idle the same as before. If good, take truck for a test ride. 

Lift Pump:

Once you modify your inj pump and run some bigger injectors, you may find that your fuel system can’t keep up with the demands. The stock lift pump struggles to supply 400hp worth of fuel and pressure. Once fuel pressure falls below 25psi at full throttle, your throttle response, power, timing suffer and smoke output increases.

DieselTuff offers a modified version of the stock mechanical lift pump called a HVHP ( high volume, high pressure ), which flows more fuel and maintains higher pressure. Capable of supporting 700+hp. Use the HVHP pump with factory heater/strainer housing or remove & install a heater/strainer delete kit, which is simply a spacer block & 2 gaskets.

12v Cummins Valve Lash Instructions:

This procedure must be done with a cold engine or at least coolant should be below 100°F.

The procedure below is called the valve overlap method. Basically the pistons have running mates. Running mates are pistons that go up and down together in exactly the same positions, as in they both hit TDC at the same time. The difference is that one of them is on the compression or power stroke, and the other is on the intake or exhaust stroke.

The first thing you need to do is pull the valve covers off the engine. Now you need to use your 1/2″ ratchet and a 22mm socket to rotate the alternator nut, which turns the belt, which rotates the engine over in the right direction for doing the valve lash and finding TDC. You want to turn it towards the passenger side fender direction. You want to get the engine at TDC (Top Dead Center) to start.

To get to TDC the easy way, rotate engine by alternator nut and watch #6 cyl rockers. Once the #6 exhaust valve closes and the intake just starts to open (move down), you stop and now you know it is at TDC on #1 cyl. This is TDC, or as close to TDC as we need to be for doing the valve lash adjustments. Now check that both rocker arms on #1 cyl are loose. If not, check # 6 exhaust rocker and if it is loose at all, then your 360° out on the crank, so rotate the engine over by the alternator nut til the harmonic balancer turns a complete 360°. Another double check for TDC is if the exhaust valve on #1 cyl, #3 and lastly #5 and #1’s Intake, #2 and #4 are all loose, your on TDC. 

Mark the 12 o’clock (very top) of your harmonic damper for reference later.

The cummins’ firing order is 153624. Cyl # 1&6, 5&2, 3&4 are companion cylinders. So #1 is 6’s running mate and 5 is 2’s, 3 is 4’s. Since #1 cyl is #6 running mate, and you know #1 is on TDC compression/power so you can do both valves on #1.

To do Step 1 of the procedure below, start adjusting the Exhaust valve on #1 cyl, then #3 and lastly #5. Then do Intake valve #1, then #2, then #4. 

Step 1  

Exhaust Valves

Cylinder Number 1,3,5

Intake Valves

Cylinder Number 1,2,4

Now rotate the engine crank 360° watching your new timing mark on the damper. Again use the alternator nut by ratchet. So now both cylinder #6 rockers should be loose. If so, good and proceed with adjusting rockers in step 2 below.

To do Step 2 of the procedure below, start adjusting the Exhaust valve on #2 cyl, then #4 and lastly #6. Then do Intake valve #3, then #5, then #6. 

Step 2

Exhaust Valves

Cylinder Number 2,4,6

Intake Valves

Cylinder Number 3,5,6

Here is the standard valve clearance measurements for a stock 1st Gen & 2nd Gen engines.

Valve Clearance

Exhaust Valves 0.020 Inches

Intake Valves 0.010 Inches

Here is my suggested valve clearance measurements for a performance 1st Gen & 2nd Gen engines. 

Valve Clearance

Exhaust Valves 0.018 Inches

Intake Valves 0.008 Inches

1st Gen Instructions & Tricks

Fuel Pump

Once you modify your inj pump and run some bigger injectors, you will find that your fuel system can’t keep up with the demands. The stock lift pump struggles to supply 200hp worth of fuel and pressure, as it will drop below the bare min 3psi. Once fuel pressure falls below 6psi at full throttle, your throttle response, power, timing suffer and smoke output increases as case pressure drops. The VE pumps timing is also controlled by fuel pressure. When fuel pressure drops, so does your inj pump timing. Not ideal. DieselTuff offers a 14psi upgrade piston lift pump kit. Much better than the stock diaphragm lift pump & the bonus of no threat of fuel leaking into the crank case like the diaphragm pump. DieselTuff’s HVLP ( high volume, low pressure ) piston pump is safe at 14psi ( more than 16psi can push fuel out the front pump seal ). Piston pumps require an install kit with spacer, 2 gaskets, hard fuel line & 2 banjo washers for install on all Cummins engines. Good news, we have it all.

VE Pump Diagram

All Adjustments can be made without removing the pump from the engine.

Low Boost Fuel Delivery Adjustment (Smoke Screw):
See: Smoke Adjustment Screw in diagram 

  This adjustment is fairly simple and will help considerably around town at low engine speeds and low boost conditions. 

  There is a small tin cap in the center of the ‘air fuel-control’ device atop the pump (the ‘appendage’ that is plumbed to the intake manifold and restricts the amount of fuel injected until the manifold pressure is above atmospheric).  This cap can be readily removed with two small screwdrivers and a gentle rocking motion.  Beneath the cap is a torx T-25 screw and a lock nut that holds it.  The locknut is 13mm and has a ‘break-away torque’ of around 100 in-lbs.  Turn the T-25 screw 2 turns clockwise and tighten the locknut to 125 in-lbs. For additional pre load fuel (and smoke) the screw may be turned farther (CW). Back it off (CCW) to reduce smoke.

Full Load Fuel Delivery Rate Adjustment (Fuel Pin):
This adjustment will TURN UP THE POWER and smoke. (NOTE: this will raise the EGT’s very quickly at full throttle): 

  The main adjustment (effects are similar to swapping the torque plate on the P7100 pumps) is found under the AFC cover. The AFC cover is held on with a 4-screws and the boost line from cyl head. Remove the AFC cover. MARK THE POSITION OF THE RUBBER DIAPHRAGM, then remove the diaphragm — there is a stamped punch mark on it, so use a magic marker or scribe to note the position of the diaphragm vs. housing.  Remove the diaphragm and shaft, and note the shaft is both tapered and on an eccentric.  Usually, rotating the fuel pin shaft 90-120 degrees clockwise   to the richest (smallest diameter, effectively) part of the shaft. You may want to start at 90 degrees and then go farther if that does not produce the power you want. The farther you go, the higher and faster EGT will climb. The fuel stop pin rubs up and down along this shaft, and note the way to install the shaft that allows maximum travel of the fuel stop part that hits this shaft and is perpendicular to it. 

  Just pay attention and mark stuff so you can put it back the way it was, and you should be able to figure it out just fine. After adjusting the diaphragm eccentric, the low boost fuel rate may need to be adjusted slightly to reduce low speed smoke. 

Clarification of how the full load diaphragm eccentric works :
  The eccentric tapered pin that’s attached to the diaphragm is the FUEL DELIVERY RATE pin (fuel pin). Now from above, looking down at the pump, almost to the bottom of the bore that the delivery rate pin came out of, is the bore that the trigger or action pin rides in. The linear axis or centreline of the action pin is parallel to the axis of the pump drive shaft, or the engine crank shaft. The movement of the delivery rate pin (down with increasing boost levels) allows the action pin (which by internal spring pressure is contacting it) to contact the increasingly smaller diameter. This allows the action pin to move rearward, which increases the fuel delivery rate. As a note: according to my books, and Bosch injection manual, the “stock” or base line for the diaphragm position is 12:00 as you look at the pump. In other words, the tick mark is toward the valve cover, for the normal setting. I have seen this not to be true on at least two trucks, one of which was on my own. If you look at the underside of the diaphragm, and can see where the eccentric would push the pin in deepest toward the front of the pump, that is the LEAST delivery rate setting. Consider that 12:00. I’ve found that rotating the diaphragm clockwise from that point to 3:00 is a good place to go. Depending on the injectors that are in, and your turbo boost, you may want to turn a little more. 

  There is also a way to improve the around town power that doesn’t require flooring it. Under the diaphragm there is a nylon washer stop. It looks like a thick washer. This stops the eccentric from traveling down too far. Shave/Grind off .090″ off it. This will allow slightly more downward travel of the fuel pin.

 AFC Star Wheel Adjustment:

 Under the AFC diaphragm and spring is a star wheel adjustment which sets the spring tension on the fuel load delivery rate diaphragm. If your star wheel (under the AFC spring) is set too high, the delivery rate pin won’t move downward as it should with increasing boost levels. Turning the star wheel up (counterclockwise) increases the spring pressure, and slows the delivery rate. I’d suggest turning the star wheel down (clockwise) in 1/4 turn increments until you smoke, then back off (counterclockwise) till smoke is gone to your satisfaction, or smoke on under power, a black haze, not a black soot cloud. The retaining lock spring doesn’t have to be removed, the star wheel will rotate with a small screwdriver gently placed and pried between the wheel and it. Note the location of the wheel, mark it, and count any turns for reference. Remember: Star wheel down=less spring resistance=increased fuel delivery rate. 

Now put everything back together the way it came apart (line up your fuel pin the way you want it. 

“DON’T OVER TIGHTEN THE BANJO BOLT ON THE AIR LINE!!!!” This bolt is very thin walled. Take careful notice how loose the bolt actually is after breaking the paint loose. 

Full Power Adjustment:
This power adjustment screw (power screw) is located at the backside of the injection pump under a thin metal cover that will pop off with a large screwdriver. Mark or measure how far power screw is into the pump before removal so you will have a base to refer too. There is a jam nut that must be loosened and back the power screw all the way out to remove a steel collar tack welded on this screw, which must be removed to allow this power increase. Grind off this collar at the tack weld (be careful not to damage threads) To remove the metal tack collar on screw, it is best to use a ‘Dremel’ type grinder.

Install power screw back to factory setting, and then turn in another 1-2 full turns.

Once you have done the above, you will probably need to reset the idle    speed adjustment. Loosen the lock nut and then unscrew (reduce revs) or screw in (increases revs) the idle stop until you get 750 – 800 RPM, then tighten the lock nut and recheck you haven’t moved the setting. Also it is a good idea to adjust throttle linkage for maximum movement.

 Idle Adjustments:
Tricks to get at the idle adjustment:

    R #1:   One trick is to use a hole punch and tapped the locknut a little to loosen it up. Then a small pair of pliers to turn the screw up or down. This seemed to work the best for me without pulling everything apart. Good luck, it is frustrating.

    R #2:   Take a 10mm box end wrench and bent the box end portion at 90 degrees to the rest of it and put it on the lock nut with the handle coming out toward the front of the pump. Then clamped a small pair of vise grips on and that allows enough of a turn on it to loosen and tighten the nut. Adjust idle with a small screwdriver.
    R #3:   I took the dremel grinder to the end of the idle screw after I got so aggravated at trying to fit the darn wrench in there to adjust my idle. Oops! It worked though, and I have plenty of adjustment if I ever need to turn it back up.
    R #4:   A “tubing” wrench will work on the nut, but turning the screw is another matter. You might try a rubber hose slipped over the screw if it isn’t too tight.
    R #5:   Buy a 10mm banana wrench for this job. Once I get the locknut loose the screw will loosen itself (reduce idle) with the engine idling! I use a small jeweler’s screw driver to turn the idle screw.
    R#6:    Tap the edge of the idle lock nut with a small flat chisel to break it free. Once the idle is turned down tap the nut back the other direction to lock it back down. 

* Make sure you adjust idle before adjusting timing, as it is way easier before timing.


The benefit to advancing timing is, it allows the fuel to be injected slightly earlier, which allows the fuel to atomize longer and will burn more efficiently, along with lowering EGT’s. The more fuel you have with more timing will make more power.

 It is impossible to advance the VE timing too far by bumping timing only. So, do not worry about playing with timing to your liking/set-up.

There are (3)- 13mm nuts on studs from gear case and (1) -10 mm bolt on back/lower bracket on pump. Loosen bolt and nuts and push/tap top of pump towards top of engine 1/8th of an inch with a soft blow hammer. (If you leave the easiest to get to nut hand tight to stop pump from bunching)

For a reference on movement/measurement, you can look beside the easiest to get to nut on pump/gear cover, which has an index mark and gear case has one too. Tighten nuts and bolt and your done.

Additional Notes:

The injection pressure of the VE injector pump is not as high as the P7100 pump used on 94-98 models. For additional power with the VE pump, larger injectors, custom fuel pin, larger turbo(s) can be installed to make a lot of power. Some engines do not respond to pump adjustments as well as others for some reason. In cases like where the pump is maxed out with little to no improvement, increasing the injector size will flow additional fuel. Non inter-cooled trucks built before January 1, 1991 they have larger injectors and delivery valves and will respond better with pump tweaking alone than the later model trucks. 

Adding a modified mechanical piston lift pump in place of the stock diaphragm lift pump, to supply the injection pump, is also highly recommended with fuel mods. The 2nd gen piston lift pump puts out to much pressure for the VE injection pump shaft seal and will blow out and dump fuel into the oil sump of engine. DieselTuff sells a modified piston lift pump that puts out the max safe fuel pressure for the VE inj pump.

Fine Tuning:

If you have excessive smoke after making pump adjustments: 

If your smoke is only at full throttle load – back off the full load screw. 

If your smoke is at idle only – Back off the smoke adjust screw on the top of the diaphragm housing.

 If your smoke is at light throttle accelerating, adjusted the “star wheel” under the diaphragm up slightly.

89 to 93 Rams used 18 cm2 and 21 cm2 turbine housings on the turbocharger. These large housings do not produce enough boost at low RPM if you increase the fuel significantly. Consider replacing the turbo housing (available from DieselTuff) with a 14 or16cm housing to improve boost and keep the EGT in the safe range.

The exhaust pipe leading down from the turbocharger is also a known bottleneck. Exhaust improvements will reduce EGT significantly above 2000 RPM, and improve turbocharger spool-up at low RPM. DieselTuff also offers free flowing exhaust systems. 

Have fun. 

VE Spring Install: (compliments of the late Robert Coe aka Paster Bob and myself)

***Clean entire pump and dry before preforming this install

1) Mark current pump timing locations on pump and gear cover, then loosen pump and let drop towards the drivers fender. (If you are unsure how to do this, look at the timing instructions above on how to do this)

2) Disconnect the throttle linkage at the throttle arm/lever on the pump.

3) Remove the TPS, AFC cover and diaphragm/cone from inside.

4) Mark/note position of all the screws such as idle, full fuel (power), high idle etc.

5) Remove the idle screw, full fuel (power) screw and high idle screw. This is needed to access the 4 main allen screws that hold the pump top on. You may get away with leaving one or two of the above screws in.

6) The allen screws on the back (engine side) of the pump top can be hard to reach but you MUST have a good grip on them even if you need to tap/hammer the allen key down into the allen heads. You really DON’T want to break one off..

7) Remove the 4 allen screws. 

The allen screw on the fender/front side of the pump (large 8mm) serves more than one purpose. It holds the throttle shaft in place, the spring(s) underneath such as the “breakover spring” and the head of this allen screw is were the TPS shaft rides, on the auto tranny equipped trucks. Once the screw is removed look down into the hole… you’ll see a tiny slender black stem with a slot in it. This slot position is very important since it is the “index mark” for the throttle lever.

8) The allen screw noted comes off in the following order; allen screw, throttle lever arm, breakover spring, washer, (at this point you should see a flat plate with tick marks like a clock on it. Note the position of the slender black stem in relation to the tick marks. In most cases the slot in the stem will align with the second from bottom and second from top tick marks… kinda like 4:00 and 10:00 so to speak.)

Try to leave the lower spring, cup, mount in place. If you have to remove the entire assembly, pay attention to how the large spring is anchored on each end, and the relationship of the plastic “cup washers”. Once you progress to removing the pump top, you will loose some fuel from inside the pump so have a drip pan below to catch the dribbles.

9) VERY CAREFULLY lift the pump top upward about 1″ while looking under it, paying attention to the back engine corner (firewall end) were the governor spring is connected. You should see a slotted piece of metal with a what looks like a tophat w/tiny spring IN the slot (careful this puppy can jump out on you once you’ve removed the governor spring attached to it and, an extra pair of hands makes this part easier). On the inside END of the tophat is the one end of the gov. spring. Using forceps or tiny needle nose pliers, carefully unhook the spring from the end of the tophat. (some people prefer to push the shaft out of the pump top instead of trying to un-hook spring while holding pump top….beware, pushing shaft out may cause a fuel leak when back together !!!!)

10) Turn pump top over and remove the other end of the gov. spring from under the pump top. At this point we need to go back to the “guide pin” that pops out inside the AFC housing… you had to push it into it’s hole to get the diaphragm out…. what you need to do, before putting the top of the pump back on is wiggle the little lever on the inside of the pump to push the guide pin back out into the diaphragm hole. This helped me get the top of the pump back on without getting “hung up”. Do what works for you.

11) Attach one end of the new gov spring to the underside of the pump top, and very carefully attach the other end to the same spot on the tophat. (don’t worry, you can’t put the spring in the wrong place, just be slow and careful.) Turn the pump top over and roughly set the shaft with the index slot in it…. that assures the internal lever with the spring is in the right location for proper rotation.

12) Lower the pump top back down in place, shifting it slightly to seat it in place.

13) Check your index marks as you begin the reverse process of assembly. (Most mistakes are done here so take your time)

14) Tighten the allen screws to 18 ftlbs.

15) Reverse the process of disassembly and tighten as you go.

16) Once all the screws, AFC, housing,TPS, etc are in place, return pump to timing marks you made on the pump body/gear case and tighten it down. Here you’ll have to get as close as possible to original screw positions for your idle, high idle, full fuel etc.

When you’ve gone over everything 3 or 4 times to make sure you’ve done everything, you’re ready to try a start up and idle.

**NOTE** Remove the air inlet tube from the turbo inlet and move to the side. Have an emergency board or whatever to cover the turbo inlet in case of runaway condition. A second set of hands helps here too, while you activate the manual shutdown lever (in case of runaway) your help can cover the front of the turbo to starve the engine of air)

17) Start the truck….. hope it keeps running. It may need several tries due to fuel loss from removing the pump top.

It should pretty much start right up.. it may stumble and clear up OR, you’ll have to re-prime using the lift pump handle or plugging the filler spout with a rag and shooting compressed air in with a nozzle/air hose to force fuel thru to the pump. (If you do it this way, make sure someone is watching the low pressure bleed screw on the side of the block and tighten it when you get a steady stream of fuel from it.)

If it starts with some throttle but will not remain running at idle, it mat be necessary to re-index the throttle lever shaft to the index mark or double check that you screwed the full fuel (power) screw to the thread index you originally marked.

At this point it should be running the same as it did before you started the install. If it doesn’t, double check everything !!!!!. Try ‘burping’ the throttle a few times. Make sure that the engine returns to idle promptly as it did before the spring change. If it lingers at higher RPM and slowly drops down, take that as a sign of being close to runaway condition. Back out the full fuel screw 1/4 ~ 1/2 turn, restart and try again. I also recommend running your high idle screw in a fair bit to make sure you can “work up to” you intended high idle setting and avoid RPM flare. You should be able to reset your low idle, full fuel, etc without too much trouble.

Take a test drive and enjoy.

VE Inj pump re/re:

To take the inj pump off, you simply take the fuel lines off, inj lines, electrical connections, oil fill neck on front engine gear cover, inj pump gear nut (you will see it when you take oil filler neck off), then rotate engine over by hand using a 22mm socket on alternator while looking at pump gear key way through the hole opening where you took off the oil filler neck…(once the pump gear keyway is close to the 12oclock position, this is the safest position to pull pump….if your anal & insist on putting the motor to TDC, well on a 4bt that’s not a problem as keyway is approx 11oclock, but on a 6bt the keyway is approx 5oclock & can fall out easy enough). Take note where the pump to gear housing timing marks are positioned if you are happy with where your timing is at (if you plan on advancing timing on re-install don’t worry about them). 

Remove 10mm bolt at bottom right of inj pump/rear bracket and the three 13mm nuts holding pump onto front engine gear cover. Pull inj pump slowly straight back being careful not to have inj pump shaft keyway fall off shaft. Once out, put keyway somewhere safe for when you re-install pump.

When you go to re-install inj pump, you need to unlock inj pump shaft lock nut by loosening nut and installing keyed washer and tightening, then rotate pump shaft so keyway is close to the 12oclock position for lining up to gear keyway on install (this is not how the manual say to do it but I find it is a much safer/faster way of installing pump as mentioned, as keyway can’t fall out easy and most are going to advance pump timing anyways). Insert key on shaft and do the reversal of the removal process above. Tighten inj pump shaft nut to 50ftlbs while using 22mm socket on alternator nut for holding engine from turning over.

Then its also a good idea to advance VE pump timing using instructions provided on my site.