Fuel pumps, are they only available at the dealer? $865 seems outragious. I don't have the service manual yet.....should I wait on it before tackling the job myself?

The dealer's diesel mechanic and a GM tech on a conference call confirmed that the fuel pump needed to be replaced.

Here's what wrong: After the engine has run for 5 or 10 minutes, the engine will not restart. After it has cooled down below 170 (anywhere from 45mins to 2 hrs), it will restart or I can restart it immediately by priming the pump. In the morning when the WTS light is present, the engine starts immediately. The mechanic says the seals in the pump are not functioning properly when hot. The only time I have a problem with engine performance is when I'm in Tow/Haul and reach OverDrive (or whatever gear it is) at a speed around 60 or 65 (can't remember exactly) and at about 2500 or 2600 rpms. I then get a SES light with a code 93 (large fuel leak) and the computer puts the engine in a limp mode. The mechanic says that makes sense since the pump is not able to put out enough fuel/pressure as what the computer is calling for at that rpm. I can then take it out or Tow/Haul which allows the transmission to shift at rpms below 2000 and make it to where I'm going without incident. This has happened the 2 times I have towed something. The two trailers I towed eached weighed around 6000 #'s and not the reason I bought this truck. I bought the truck to tow 12,500 #'s more easily than what my 1986 E150 with a 302 could do. It was able to do it, but it's tired. BTW, I made major changes to the E150 so that it could handle the job.

Any answers to any of what I've posted would be appreciated.

Tom

I'd be willing to bet it is injectors..

How could the injectors keep the engine from starting when hot and why would the engine start when it's hot just by priming the pump? The injectors were replaced 3 times, the last time was at 30 something thousand miles when they were replaced with the newly engineered injectors. The mechanic considered the injectors initially, but ruled them out.

When I joined The Diesel Place, I read through as many forums and threads as possible just because I was interested in learning as much as possible about my newly acquired truck. At that time, I read some posts talking about buying a fuel pump on ebay (I think) for somewhere in the $300 range. I've searched all over and can't seem to find anything that discussion anywhere. Anyone out there that can help me out??

tom

I'll bet the stealer is talking about your high pressure pump (cp3?) I'm pretty sure the fuel pump from ebay or the others that vendors on here sell are lift pumps to help keep your high pressure pump full. People are now looking into modifying the high pressure pump to allow more fuel flow for performance.... I'm sure others will chime in, but like I said, I think you're thinking lift pump and dealer is thinking the high pressure pump..
Jason

No, I'm not thinking lift pump, because there isn't one. There is only the high pressure pump which is two stage. I am considering installing a lift pump, but right now, I'm just trying to get the current problem resolved.

But, you are right, the posts I remember reading may not be for the same pump, although, I do remember that the person initiating the thread was complaining about the same thing (their dealers price was $845) and they were directed to ebay. I didn't know that I had a problem when I joined and was reading everything I could, or you can bet that I would have chimmed in on that discussion.

There are many things that can cause what you seeing.

You need a Tech II to diagnose the CP3. The tech will command it to hit pressure, and it will show whether or not can hit commanded pressure.

I'd certainly make sure every stone was turned before replacing it.

I'd put a $80 lift pump on, and look for fuel leaks first.

Thanks, McRat.

What's a Tech II?

I take it that the fuel pump, which is located somewhere near the top/front of the engine, is called a CP3?

I don't think I have a fuel leak....no visible signs and my mpg (15.6) is good and actually improving with the TURBO3000D I've installed. It is my understanding that the Fuel Pump has a check valve of sorts and that the fuel is leaking back to the filter. When its hot, the check valve/seals don't seat properly allowing the fuel to flow back to the filter. I don't know why it wouldn't flow all the way back to the tank, but there's a whole bunch of stuff I don't understand, yet. BTW, when the engine is hot and I shut it down, it will immediately restart without a problem since the fuel hasn't had time to leak back to the filter. If I wait more than a couple of minutes from the time I shut it down, it won't restart without priming the pump.

I've thought about installing a lift pump so that the CP3 will get primed without me having to do it manually, but I'm concerned that in the long run that the CP3 will fail completely because of bad seals. The dealers mechanic says that he has never seen or heard of a CP3 failing completely. Any thoughts?

sounds like you either have an air leak or the injection pump is faulty.I would start by replacing the 2 low side fuel hoses(before and after the fuel filter)with clear hoses.prime the system,start the engine and look closely for air bubbles in the hoses.if air is coming out of the fuel filter housing the housing is bad.if its coming out of the FICM,replace the FICM.both are common.if no air suspect the pump.

Sounds like a good idea: replacing the low side hoses with clear hoses..... I have, however, already replaced the hose from the filter to the pump because of installing the TURBO3000D. I'll go ahead and replace the one feeding the filter since I didn't like the way the hose felt that I did replace.

That still leaves a question unanswered: Why does the engine crank easily when its cold. If I have an air leak at/around the filter, shouldn't it be just as difficult to crank when it's cold?

just helping you eliminate things,a tech 2 should be hooked up and with the engine hot command the fuel rail pressure to 160 mpa.it shsould at least hit 155.if not you either have high return rates on injector(s)or a bad pump.actually the tsb states to replace all 8 injector first and if pressure is still not reached replace the pump.but since you state that it starts right up after a prime I would guess pump.

Sounds like a good idea: replacing the low side hoses with clear hoses..... I have, however, already replaced the hose from the filter to the pump because of installing the TURBO3000D. I'll go ahead and replace the one feeding the filter since I didn't like the way the hose felt that I did replace.

That still leaves a question unanswered: Why does the engine crank easily when its cold. If I have an air leak at/around the filter, shouldn't it be just as difficult to crank when it's cold?

_____________

You may just want to try an inline check valve (to prevent back flow) between the filter and the pump. See what happens. Cheap enough and easy enough to do.

Mudbug - what a great idea. So, where would I get a checkvalve? Are they readily available at the parts house? I guess that if the check valve solves my problem of starting, then it has to be the fuel pump which I will need to eventually replace?

When the injectors are bad there is too much fuel going through the return line and the system can't build enough pressure for the truck to start. It happens when its warm only until it gets worse.

I know of 2 people who have had the exact same symtoms as you and both had their injectors replaced and that fixed the problem.

Mudbug - what a great idea. So, where would I get a checkvalve? Are they readily available at the parts house? I guess that if the check valve solves my problem of starting, then it has to be the fuel pump which I will need to eventually replace?
_Any hardware store would have one. A 3/8" brass bodied plumbing one would work - this would just be for a temporary checkout, right?Max Power's note would seem to pack the weight on what you're looking for, though. Running ok unloaded but limping in a heavy tow would seem to indicate pump or injectors (tranny putting you in limp, maybe?). If it was an air leak, it would seem to be most all of the time to me.You dont mention anything about heavy smoke as it seems to limp before that while towing?? What I'm "guessing" at here is the injector part.I'd write down each analysis piece of this along the way until you determine what the true problem actually is. Just my 2 pennies but you may be $ and hours ahead by paying to have it put on an analyzer.Mudbug