Hi everone, I have not done alot with the duramax motors and i am in need of some advice. I have attached some screen shots from my snap-on solus pro scanner. The truck is a 2002 LB7 115,000 mi 4x4. On hard accel. it falls on it's face, if you drive easy ( normal ) no problem. I have changed the fuel filter twice in a week. I ran all the fuel out and filled agin with a new filter, still the same problem. The attached files show at idle and when the problen happens. I dont know if it is the reg. or pump.


THANK YOU FOR YOUR HELP IN ADVANCE.

JEFF

Couldnt find a P1039. There is however a P1093 which is a fuel rail pressure sensor code.

Last paragraph from the service manual..."If a sensor circuit malfunction is detected, or the commanded fuel injection pump flow is not within the proper range for a given engine load and speed, DTC will be set.

Thanks for the reply ski. I was wrong the code is P1093, fuel pressure low while power enrich. I belive the problem is the regulator but not shure.

Thanks agin.

If the fuel filters were clean (assuming you dumped them out and checked ) then it's time for a pump and it does come with a new press.regulator. Let us know what you find.

I'm in the same boat!! Mine does exactly the same thing!! Going to have a pump and FPV put in next week. Hold on to your wallet!!!

The first filter was dirty but the next two were clean.

This is absolutely positively the most common problem on LB7s. P1093 or P0093 (same thing). Besides injectors;)

EFILive is your friend. You can basically turn this code off by adjusting a few things. The issue will still exist (lower than desired fuel pressure) but once you disable it, the worst thing that can happen is low power output.

This is absolutely positively the most common problem on LB7s. P1093 or P0093 (same thing). Besides injectors;)

EFILive is your friend. You can basically turn this code off by adjusting a few things. The issue will still exist (lower than desired fuel pressure) but once you disable it, the worst thing that can happen is low power output.

If left long enough, I think the pump would be unable to build rail pressure for start up, leaving you stranded. This code is showing a fairly large drop off in performance, so instead of brushing it under the rug, it would be my advice to address the issue properly. I just upraded to a LBZ pump, after a year of the p1093, and it was like driving a whole new truck. Truely a night and day difference in performance.

Fixing the issue should be a priority, but the fact of the matter is it's not usually a catastophic fuel leak, just a CP3 that's slowly dying, bad fpr, air getting in before the pump, something like that. 99% of the time it's not something that's going to leave the truck inoperable in 50K miles even. You will get a 1094 before the truck calls it a day.

Deleting that limp code lets people use their trucks for their intended purpose in the mean time, instead of getting run over by a log truck while pulling a grade when their engine loses power. The limp is dangerous, and should never have been associated with a P0093/1093. A check engine light would have been plenty.

I was getting that code only when towing my camper. A new pump cured the problem (and drained the wallet)

I cured my truck of the p1093 and p1094 codes a little while back with a new CP3. Its pretty crazy how many im seeing go bad on here now, I thought I was just unlucky. Are any of the newer trucks experiencing problems like this? I know a lot of the guys are upgrading to the LBZ pumps because they flow a little more. Are they all the same design for each engine model? Hate to say it but along with injectors being a well known problem among us LB7 guys.....it almost seems that a CP3 pump failure is something to warn potential buyers of.

I put a new FPR, dual lift pumps, on my truck only to fix the CP3 and the 1093 went away. Easy tests:
Get two lengths of clear hose, approx 1/2" in diameter about 8in long and 1-2 feet.
Put the short hose between the fuel filter out let and the other end, if you see air bubbles then your getting air in the cp3 and that might be a problem(its a problem)
The longer length: move the air conditioning compressor, remove the stock rubber hose from the cp3 output and put your hose inbetween the hose you took off and the pump, thats the return line from the pump, then loop the fuel line so you can see if when you put the air compressor back on. Do that and start the truck, if you see bubbles coming in that line your pump is bad because no bubbles should be coming from the pump. You could use the return line located back by the Glow Plug controller as well but I can't remember if that isolates the cp3 return line.

Thank you all for your input. over the weekend I replaced the pump and cleand the fuel lines ( two were pluged ) and I still have the same problem. I will do the air bubble test and see if the filter housing is leaking.

Thank You all agin,
Jeff

i would've done the air bubble test before replacing the pump, imo. At least we know its not the pump now...

How much does it cost for a new fuel pump?

The code appeared after new injectors. Dealers say CP3 is bad. Truck is dead in the road today, cranked over but will not start. Its getting towed to the dealer for new CP3, I will give a up date on this truck,93000 on the clock. LBZ bought it new in 2002. Joe

Mine has been getting the P1093 code for a couple of months now, and just yesterday I also got the P1094 code(low pressure at idle). Are these codes only caused by the fuel pump, or can they be caused by bad injectors also.

The code appeared after new injectors. Dealers say CP3 is bad. Truck is dead in the road today, cranked over but will not start. Its getting towed to the dealer for new CP3, I will give a up date on this truck,93000 on the clock. LBZ bought it new in 2002. Joe
The Lb7 is fixed, for now. The pump quote was 2100. The dealer did it for 1100. Same dealer with GM help on parts. I am going to install a lift pump and extra fuel filter this week to see if I can help this fuel system live. Joe

JDBLBZ...good idea. I have a lift pump and pre filter with 173K on the clock. My pump still can deliver commanded pressures easily.

maybe stupid question, but does a lift pump and second fuel filter help increase the life of the injection pump?