Got a weird thing going on with my truck

mountainar15

New member
Joined
May 9, 2008
Messages
3
Help! I need an expert or something. I've got an issue with my LLY that I can't figure out. It has a total dead spot off of a stopped start and again in 5th gear between 50 and 70 mph. On a start, the truck is really slow to build boost and get moving. If you try to power brake it, it will build about 3.5 to 4 pounds of boost (1600 rpm range) and then it's like a switch just shuts it down. It won't build boost beyond that and won't do anything. Kit blows a little bit of black at this point, but not much. If I let the truck roll a bit to build rpm and boost, it will usually light after 2,00 rpm and 6 pounds of boost.
In 5th gear. if you're rolling along at anywhere between 50 and 70 mph and roll into the throttle without letting the trans downshift, it's like nothing is happening. No acceleration, no boost, no response. It generates a tad of black smoke, but no more. If it downshifts, it blows a cloud of smoke and takes off. If it builds enough speed to get up to about 75 mph and can increase boost, it will also take off in 5th.

Now, here's what's on the truck.
Garrett 4094 turbo with PPE pedestal and downpipe
PPE Hot +2 ET tuner (been testing on 6) - Also tried known-working EFI live tunes
intercooler
Dynomite 50-horse nozzles
150 GPH AirDog pump w/suction tube (19 psi upside of CP3)
Modified single CP3 (Industrial Injection)
Duel feed line
PPE Race fuel rail valve (also tried shim kit) & bored fuel rail in-line fitting
Blocked EGR
Sun Coast stage 4 with 1058 converter

Even with the fuel release valve shimmed, the truck would through the 1093 (low fuel pressure) code when you try to power brake it and sometimes at the dead spot in fifth gear. I've even had the 0087 code. With the race valve plug in it, I have still gotten the 1093 code once during each situation.

Turbo shows 3.4 psi boost at 75 mph in OD, and 0.0 psi at 55 mph range.

Any ideas on what I'm missing here? I've had people tell me it's everything from wrong torque converter to getting way too much fuel to not getting enough fuel.
 
Try changing fuel filter? If you have access to a scan tool or EFI Live try data logging the commanded vs. Actual rail pressure. It sounds like actual is falling off causing it to go into failsafe.
 
I changed the fuel filter right when we first noticed the problem. Still does it. I have watched the desired vs actual on the PPE tuner in scan mode, but it doesn't show the ten-thousands digit, so I don't know if I'm getting 26000 or 16000 psi. Would a Bully Dog Outlook monitor show that data? I've got one of those laying around...

Also, since putting in the PPE race valve plug, I don't get the 1093 code unless I try real hard in the brakestand-no boost mode.
 
Possibly have an injector or more that is returning more fuel than it should causing the cp3 to not be able to supply enough volume?
Or pump going south?
It would be alot easier to diagnose with a tech 2.
 
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