I'm looking for a little help with my P7100 pump. The truck is a 93 Ford F700, 6spd STD 5.9 12v P7100

Mod so far:
#100 plate
3k GSK
AFC foot ground flat on face and barrel shortened
AFC diaphram washers ground
No boost line going to turbo at all (stock)

I first tried the #100 plate with three clicks on the gov springs and it pulled 15000 pound trailer great but idle was at 1000rpm so I got some 3000-4000 gov springs and it's been downhill from there. After the springs the idle was 800 and takeoff was good but after 2000rpm it falls totally flat and looses power big time going up a grade and that is without any load. Where have I gone wrong here? I'm thinking of going back to the stock gov springs but there has to be a way to fix this. Smoke is not all that bad if I go easy. I tried it with the AFC gutted (to eliminate variables)today but still no real improvment. I have been looking for info on gov arm adjustment. Any good garages here in the New Hampshire/ New England area that you folks would recommend that know the P7100 and the cummins 2nd gen motor. Any help would br greatly appreciated.

 

after you installed the 3k to 4k springs how many clicks on the springs did you use?

sounds like it could use another click on both sides

 

Thank you for the promt reply.

In order to follow the instructions that came with the springs, I needed to take a measurement from the top of the spring seat to the top of the retainer nut, so I backed out the stock spring retainer nut three clicks to the original postion and measured .040. That was where I set the new ones to.

The instructions also said not to put the original shims back in which seemed wrong but like a good soldier I followed orders. So if I tighten the preload on the springs won't that also increase idle back up to the 1000 which I was trying to avoid?

Also, following the changes I've made on the AFC, #100 plate and the GSK should I increase timing? I was thinking of increasing the timing to 19 or 20 but was holding off until everything else was squared away.

Are there any good posted instructions on adjusting the timing? I guess you can't just loosen the bolts and give it a tap or a slight pry??? HaHa

 

your idle will go up as it should, there is a low idle screw that you will have to adjust on the back of the throttle linkage to bring it down to normal.

A timing bump would be great, IMO stay below 16* until you get some head studs

 

Ok, so you feel pretty sure I have a governor issue.

I'll try today to give it some clicks until the desired performance is acheived.

While I'm in there....... On my AFC, which is currently gutted, I was playing around with that off the truck and was able to cycle it through it's stroke with air. The way I had the star wheel set before I gutted it was full movement at about 20-25psi. Should I return to that or is there a more optimal setting for these.

 

thats something you will have to play with when its on the truck, you have a baseline and you can tweek it from there

 

is your boost line going to your manifold? check intercooler boots for leaks. springs should be .040 to .050. i measured mine three different times just to make sure they were equal. thats is just my 2 cents.

 

x2 would not hurt to check these things as well

 

I want to start out by thanking you all for the help.

The truck is running great now and I'll be going back into it today to double check and do some more fine tuning but as it sits right now the troubles seem to be over.

Here's what I found.

It seemed to me that everything I did just kept getting worse and worse with every additional adjustment I would make. I was following all the directions to the letter and reading everything I could find on the web. I tuned the AFC. I tried to eliminate the AFC by gutting itso I could just have it run on the fuel plate. I built a air hose adapter to test the stroke of the AFC.

When I pulled the stock gov springs it had 4 shims ( 080.") on each side so I took every thing apart and compaired gov spring sets side by side and measured every component. I tried it without shims with .040 then .060 then .080 then with two shims and again 40, 60, 80. Still it would just keep getting worse.

It wasn't until it stalled out trying to go up the test hill that it occured to me that the thing just wasn't getting enough fuel. I hadn't tred anything radical with any of the adjustments and it would run up to 17-1800rpms pretty good but any load it would die.

Final resolution.... fuel filter and strainer. What a dope! Man... the strainer was all gummed up with brownish red crud. No wonder!!!! The thing is... it was running good before doing all of this but the extra demands of the increased POWER! and I do mean power, pushed the fuel system over the top to the point where it could no longer supply enough fuel.

I learned a lot along the way and I can now take that AFC off and adjust the plate and gov springs faster than a nascar pit stop. It was a cool journey... a bit frustrating but what the hell........ this baby rips now!

Thanks again

P.S. when doing the gov springs cut a small piece of aluminum flashing (or beer can) about 2" by 3" bend it with a curve to slip in under the spring so nothing can fall into the pump. Round the edge's so you don't get too much blood all over the place. A piece of .060 wire bent sharply at one end and ground sharp can get the shims and springs out in no time flat. Instructions for the GSK say use magnets and a small screwdriver ( I don't know what they're smoken) but I found that needlenose plyers and the two pieces discribed above are just the ticket.

 

very cool glad you got her fixed