Engine/Transmission (1994 - 1998) Injection pump issues at full load OD after GSK

[dieseltech8100]

Someone has to be able to help me here. I hooked the fuel pressure gauge up and I am running around 27 psi at idle and it dips down a little. The lowest I saw was 25 or so psi and the highest I saw was 42 psi or so. And when the truck hits OD it is not pulling hard like it did. It hazes at WOT from take off til full lock up OD but just has nothing in OD. When it shifts into OD it actually will drop from 1400 (that it hits normally at WOT) to 1000 on the as soon as it hits lock. Fuels strong down low and then the more load it gets on it the more the smoke goes away... Which is opposite of what should happen. Timing has been adjusted to 15, and the GSK set to the stock . 040 protrusion. I had the GSK tightened down to . 75 before and it was acting like this so I tried to change it. I got way more out of it the way I have it set now. It fuels hard down low now where it wasn't before, but it is the EXACT same way once it locks in OD. And no matter what I do, I can't shake this issue. Tried to adjust some on the shut down solenoid and nothing there either. Now I should clarify that this all began when I installed the GSK so I thought that may be the issue, but I have adjusted the GSK tight and loose and it still has this issue. I have also checked and messed with just about everything I can think of. I should also mention that it killed my MPG by like 3 MPG as well. It gets 12 - 13 MPG and it was at 16-17 before.



I really don't want to take this pump off to fix the issue. It starts fine, it idles well, it doesn't misfire, it just has a fuel issue that is not related to pressure. Also, I really watched the gauge as I was driving around now and I'd see it so high like it is and then when it really pulls hard top of 2nd gear thru most of third it would drop the pressure back to around 26 or so. Then when it hits fourth the pressure will come back up til lock-up and then is the same as no load. Kinda like something is really asking for fuel, then kinda relaxes its demand as the load increases. I'm starting to think its inside the pump.



And I can't loosen it anymore than it is. I have it cranked forward and I have the housing slid forward. I could try to take the plate out but I don't think that is the answer here either.



I am so lost on these pumps... Someone please give me some ideas... I am running out here. Anyone have a breakdown of what would make it max fuel in OD with full load? I am trying to figure out what I am missing here... Any help would be great! Thank you!!!

 

[Vaughn MacKenzie]

It sounds like your springs are too tight and the power band was moved up further than you'd like. What GSK kit did you install? What RPM does it lock in OD? Try turning OD off and let the TC lock in 3rd gear then see if it seems weak at that RPM as well. I don't think you have a pump issue just need to work on adjusting the springs some more.

 

[dieseltech8100]

Sorry, its a 4k. Don't recall the brand tho. And I would normally agree on adjusting them, but as I mentioned I had them down to . 075 and then I did not mention the stud protrusion was loosened to . 050 and it helped the low end but the OD issue remained so I loosened it again to . 040 but that only helped down low once more. This issue has remained totally unchanged by all my adjustments. Timing, stud protrusion, AFC adjustments, and plate slides so I'm just lost. I've tried everything I can think here. Oh and its only 4th lockup. I tried it with o/d off and hit the l/u switch and it pulled hard all the way through 3rd but as soon as I turned o/d on, the EGT went from the 1300 it was at back to 1000 and I did not let up. This is the exact way it acts without doing anything which is why I think there is something hanging up inside the pump. I'm just not sure as to what... .

 

[GAmes]

When it shifts into OD it actually will drop from 1400 (that it hits normally at WOT) to 1000 on the as soon as it hits lock. Fuels strong down low and then the more load it gets on it the more the smoke goes away... Which is opposite of what should happen.

That sounds like exactly what SHOULD happen. The more rpm you have the more boost (air) you have and less smoke because you now have enough air to burn the fuel. You do know that smoke is money wasted at the pump, right?



So at what RPM are the shifting points and the OD locking at? If it is less than 1700 or so you are lugging the engine, plain and simple. I would imagine boost is way down at this point also.



I suspect your fuel mileage issue is a result of how much time you spend at WOT:-laf

 

[dieseltech8100]

Ok... I think we have something mixed up here. The governer, from my reading and understanding is designed to increase the delivery of fuel (to increase power) as the load increases and then reduce it as the engine load decreases. I read this from a post on TDR dated five or so years ago with I title of something like "How's a p7100 work?" Or something along those lines.



The way the injection pump worked prior to the gsk install, it would pull decent until it locked in 4th then almost put me right against the seat. The boost pressure went way up and so did the EGT. From a stop until lock-up the boost would stay around 32psi and egt around 1000 and in lock would hit 1400 and 38 psi. Now that I have the 4k GSK its 38 psi from stop sign to lock at 1450 and then as soon as it hits lock it drops to 33 psi and drops immediately to 1000 or less.



And the term "smoke" as I used it in that instance refers to power, not actual smoke.



I'm not here to get into a dispute about my driving with someone online. This has been this way since October when I installed them so I have run a good share through the filler neck and its 12 - 13 MPG on it or driving miss daisy. This issue does occur at lower throttle as well though. It actually has a noticeable power loss upon lock as well as the loss of boost at any throttle.

 

[GAmes]

I think you are mixing apples and oranges. A GSK by itself will not change your shift points or fuel consumption. So I ask again, at what rpm is the transmission shifting and the tq converter locking?

 

[Missouri Mule]

The governor regulates fuel (along with the plate). On the stock gsk the governor cuts fuel at around 2700 rpm to 3000 rpm (if your lucky) on the 4 gsk you should be able to get to 4400rpm to 4600 rpm before the governor backs off the fuel.

 

[Vaughn MacKenzie]

Generally 4K kits are harder to tune & set up and is better suited for competitive applications. For most folks the 3K is plenty, my 3K pulls hard to about 3700 and still has power at 4000 RPM.

 

[KYOUNG]

you need to contact somebody like Jim Fulmer to work over your AFC so it will fuel correctly. It should be set so it doesnt open til 24 lbs of pressure. You need to make sure foot is contacting the plate instead of going under it!