Lost power even with TST?

[scaryfast]

I'm at wits end with my '94. Last year I installed a TST kit and WOW, what a pullin machine. This year I've lost a ton of power and I can't understand where it went. I had the injector pump rebuilt $1,700, installed a new lift pump, still no power. I live in Denver and last Saturday I towed my trailer into the mountains. I had it floored with three toes sticking through the floorboard and I still could only get 1100 preturbo EGT's, boost was 23. Last year I could bury the EGT gauge instantly if I wasn't careful. Sounds like a fuel delivery issue but Cummins RM thinks all is fine.

Is there any hope to get back my power?

 

[RHARVEY]

Have you checked the boots on the intercooler?? Mine runs 24lbs of boost stock. . Sounds like either a boot has come loose or how about the fuel filter????



Rick

 

[scaryfast]

The fuel filter was the first thing I changed, then the low side check valve, then the lift pump, then the big buck injector pump rebuild. I have inspected the fuel lines for signs of any leaks, checked the tightness of the clamps on the intercooler. All seem fine. Cummins Rocky Mountain had it on their dyno and recommended the $1,700 pump rebuild, even that didn't fix it.

 

[Alaskaskiff]

Another boost leak is through the wastegate actuator. I blew the bellows in mine and lost significant go power, with much lower boost. Break into the line and put low pressure (19-20 lbs) of air to it and see if it leaks.

 

[jeff2]

check full throttle position

 

[A Johnson]

You said that Cummins RM rebuilt the pump and that you had installed a TST kit. I assume a TST kit involved putting a rack stop plate in the pump. Could they have put a stock plate back in.

Also check your shutdown solenoid to make sure its pulling the fuel shutoff lever all the way up .

A Johnson

 

[illflem]

jeff2 beat me to it, that would be my suggestion also. Also check intake manifold bolts for tightness

 

[R.ebel]

No Power?

Another thing to check is the boost signal line to the AFC. If for some reason it is missing, leaking or pluged you will have no power (a valet switch dose the same). Keep us posted on your problem, there is plenty of diesel savy on this board to help you sort out the problem

 

[scaryfast]

You've certainly given me some new things to check and I'll get right on it this weekend. Would the things relating to boost or the AFC line being missing or plugged give low EGT temps? It does seem like my TST kit has been removed in the middle of the night. I told Cummins RM that the truck was boosted. They sent the pump to Denver Diesel for the rebuild and instructed Denver Diesel to tweek it. Surely they wouldn't swap out my fuel plate for a stocker would they?

 

[Steve Roseman]

Mr. Dee,

I'm no diesel guru, but it doesn't sound like a boost problem. I think if you had the fuel but not the boost you would be having high egt problems.

I would start with the afc, then check the position of your plate. maybe things slid out of place. Piers has a section on his website that talks about the governor lever adjustment, maybe it's catching www.piersdiesel.com.

Good luck to you.

 

[Jim Fulmer]

Mr. Dee

If it were me I would check the plate like Steve Roseman said, the reason why I say that is now I've seen two(mine and Deezul 1's) when out of adjustment there was low boost as well as low EGT, I'm a firm believer in the adjustment. With the AFC housing off advance the throttle till the gov arm hits the plate, it should be on the big nose(thinking of my #8) adjust it so it hit's on the nose or slightly below that cause I was told it will pull down slightly after running and on it, check it out today if possible(mine takes 10 min to) and let us know and well help you through it.



Jim

 

[scaryfast]

Would this be something Denver Diesel would have done when they rebuilt the injector pump?

 

[Jim Fulmer]

That might have happened but I really don't know so I can speculate on it, but if it is out it is an easy fix. Checkout piers site on it.



Jim

 

[DR]

First check your throttle linkage, make sure you're getting full throttle. Are you getting full RPMs? Then check your smoke under 3/4 to full throttle. If it's grey or black your getting fuel (the darker it is, the more fuel your getting). Then pressure test your intake, 23 lbs. of boost is not nearly enough for the 250 plate (sounds like you have a leak). 28 lbs is minimum with 32-34 lbs being optimum. Next check the cam plate, it should be in the middle. If it's been moved back, moving it foward gives you more fuel, power and EGTs.



Generally once you have the correct boost, you slid the plate to give you max EGTs. Then check your smoke, should be a grey haze, although it will lighten some as the boost climbs. Too light, less boost and/or more plate. Too dark, less plate and/or more boost. Balance the boost and fuel at max EGTs and you have optimum performance.

 

[scaryfast]

My power was low before Denver Diesel rebuilt the pump and is equally low after the pump rebuild. I have zero to barely noticable smoke at any rpm, with or without my trailer in tow, even if I really lug the engine... . no smoke. That's the way it was before and after the pump rebuild.

 

['956Wheel]

How about slipped timing? I have not throughly read all the posts so pardon me if I repaeted one.



Mike

 

[DR]

Have you checked your fuel pressure?

 

[scaryfast]

I asked Cummins to check the fuel pressure and I don't know about the timing. When I took it in, I told them it was boosted, but had low power for some reason. So I left it up to them to trouble shoot the problem.

I checked the AFC lines last night and they were fine, but the brass fitting that they attach to was about a half turn loose from the back of the AFC housing. I hoping that was it, but without hooking up a trailer, I can't really tell. I'm headed up in the mountains again this weekend with my trailer, so I will know after that.

I called Cummins RM and told them I still had no power, no EGT's and no smoke. They also said to look at the AFC lines and if that wasn't it, bring it back in. Man, I don't know if I can afford to keep doing that, those guys are expensive!

 

[DR]

Hopefully, tightening that coonection will fix you up. But, if it doesn't put a tee connection there with a boost gauge to check your boost (maybe the line is clogged). If your boost is good there, check the AFC spring. That works against the boost along with the plate to govern rack travel. I noticed you changed the stock spring, did you go heavier or lighter? The stock spring works pretty well in the earlier 2nd generations.



At any rate I would pull off your AFC housing and check the plate position before you spend more money at the shop. Honestly, the shop should have checked everthing out when they did the rebuild and you shouldn't be charged for anymore until they get it right. That's BS if they sent you on your way with loose fitting, or a clogged line or whatever the problem is and charged you a pump rebuild that you probably didn't need.



I recently had a dealer try to charge me for fixing things that weren't broken. I had OK'd an estimate and told them that I wanted to see the old parts, when I went to pick it up the bill was almost 3 times the estimate (they said that they found other problems). Then when I challenged the shop manager they weren't able to produce all of the the faulty parts. They ended up eating the labor and I got the new parts at a discount.

 

[scaryfast]

I did install a lighter AFC spring last year and had it adjusted to yield slight smoke on take off, heavier smoke if I got on it. Now there's no smoke, almost like a gas engine! There is a guy in the Cummins service department that sounds like he'd like to help me get the truck straightened out. I just don't know if he has the authority to do it no charge or not. He's even given me his cell number so I could get a hold of him, that's cool.