LBZ: Low Fuel Rail Pressure [Archive] - Duramax Diesels Forum


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06-10-2008, 06:40 AM
i have this problem that i can't fix and i need to find out how to fix the P0087 on the LBZ,now i have the 150GPH AirDog on it but when i run the PPE on anything higher then 4 with the TS MP-8 turned up it will trip it if i hit it for a short race and when ever i pull the sled it will trip it roughly 3/4 of the way thru so any ideas on how to fix the problem..i keep the fuel filter changed every 5,000 miles and i have 8-10PSI on the AirDog at full throttle so it's just the rail running low or thats what i think it is...also i have the shim kit but i'm installing a race valve as soon as it gets has almost cost me 2 races and it cost me some pulling distance the other nite at the truck pull,if you listen carefully to my pulling vid you can hear the engine loosing RPM's even while crossing the 290-300FT mark..any help would be greatly appreciated.

06-10-2008, 07:34 AM
That is all you can get with the stock CP3. The duty cycle and lack of sufficient flow is draining the rail. A higher performing CP3 will make a big difference.

06-10-2008, 08:08 AM
Check your fuel filter.

We had a customer fix the P0087 with the race valve and changed fuel filter.

06-10-2008, 11:28 AM
just changed the fuel filter yesterday..

06-10-2008, 11:33 AM
one more question,doing a bigger CP3 pump won't help me much will it with out doing a turbo upgrade or am i thinking wrong,also i have a race vavle thats going in either wensday or thursday..

06-10-2008, 11:38 AM
with the gt4094 and the ppe set on lv I could run my duramaximizer up to about a 1/4 turn anymore it would p0087 so you need to watch how far your turning that ts mp-8 up.I run the race valvbe and ported front rail fitting and a ppe lift pump.Not sure how well the wicked diesel modded regulator helps since I blew it up 2 days later,

06-10-2008, 12:14 PM
rip, even with all those things you still get the 0087 code when turning it beyond a quarter turn on the MP-8 and level 1 on the PPE???

Friend's truck throws this code VERY badly. I was hoping suggesting the race valve would fix it but sounds like it might not completely cure it???


06-10-2008, 12:17 PM
Yeah, the factory rail fittings are very restrictive. We were able to run the Duramaximizer up a bit more, when we enlarged the passage in those fittings.

06-10-2008, 12:28 PM
I can hold rail pressure with the race valve and ported front fitting and ppe lift pump and the Hot+2 et on lv6 and the maximizer 1/4 the way up any more then you cant hold rail pressure, Im also runninga larger turbo so TYREBOYZ_DEMAXIN should be able to hold if he's running a stock turbo and back his TS mp8 down some. Me im done with trying to find the single cp3 way of hold rail pressure with rebuild i'm adding dual cp3's

06-10-2008, 04:27 PM
this fall i'm wanting to do dual CP3's along with a set of twins seeing i'm a twin my truck should have twins and alot of other goodies thats if i have the $$$ and not spend it on something else by then..LOL
since the TS is only a pressure box would it not help hold rail pressure and now i realize that it also adds fuel to the engine but i didn't think it would trip the 0087 with the PPE on level 3 and the TS turned up like it did today..guess i'll install the rail fittings along with the Race hard is it to do the bigger fittings?

06-10-2008, 04:33 PM
Not hard at all once you install the race valve go to the front of that rail and you can 1 buy a ported fitting or take the one that is there and drill it to .090 thosands,I would run your ppe up on a higher lv like 6 and barley use the ts box, the ppe duamaxmizer is just a pressure box also.