Blkdth87

took the car for a good run last night, put the pedal down, and i got a good um, 10second delay before the engine felt like it was pulling correctly.
after that all hell broke loose...including my tires.

2004 gto ls1,
i installed a new fuel filter, pressure regulator is set to 45psi ide 55 full throttle, using my tpi fuel pump and lines. the pump is basically new. any ideas?? i believe the pump should handle this setup, but i can be wrong, any ideas would be appreciated...thanks.

cam-

Fuel pressure seems low and that would cause hesitation. I would start there. Should be at least 55 not max 55. LS1 installation guide claims fuel pressure should be between 53 and 63 PSI at idle. Good luck!

Blkdth87

thats the fuel pressure i started at, then i turned it down thinking i might have set it high, i'll set it back to 55@idle. and try itout. any other ideas??

cam-

Have you checked for trouble codes?

ghettocruiser

iTrader: (4)

That set up using electronic throttle control? If so might want to check that out. Almost sounds like a part of traction controll is still messing with things...even tho TCS is usually its own little system.

Otherwise, check for codes, or get some scanning software hooked up to it to see what its doing during the hesitation.

Justin

Blkdth87

04 is still cable driven throttle, 05 went to electronic throttle, only code i got in the system is for the high speed cooling fan,
by electronic throttle do you mean the throttle controller that sits with the powertrain interface module? i'm going to try and disconnet that for the hell of it and see what happens.?

can someone hook up a scanner to their car and give me at idle their maf and map readings? id' like to compare.... thanks

Blkdth87

well, i reset the fuel pressure to 55 @idle, took it for a drive, same...
disconnected the throttle position controller same
disconnected the powertrain interface module for the hell of it, same sh.t
looking for some more ideas.... maybe the traction control / abs is still affecting the drivetrain? i'm gonna call fastchip.com they removed my vats from the computer, maybe they forgot to remove the abs/traction from it also.... any other ideas???

cam-

Have you got your VSS from the trans wired up to the PCM correctly? I'm guessing blind its hard to know without being there. Another longshot could be the tune or lack thereof on the computer. Are you stock? Cam? tune?

Blkdth87

engine is stock. it had 2712 miles when i bought it, so i figured, leave it the way it was. only mods are a ram air intake and full hawks header/ypipe combo, using new ac/delco o2 sensors. i used the factory gto harness. i made an adapter harness to interface my car and the drivetrain. the computer was sent out for a tune, security delete, and some other small stuff, i told them to remove any reminence of the tcs/abs, i'm gonna give them a call today and see what they say.

ghettocruiser

iTrader: (4)

Im not sure what the GTOs are set up like...but in an f-body, the ABS and TCS are completely separate from the PCM. Like the ABS had its own brain and system, and the TCS used info from the ABS to do its thing. I think it took info from the PCM, but it didnt do anything to the PCM during traction loss. But I dont know if the GTO is different. Could very well be.

Justin

Blkdth87

well i called fastchip.com, they said it was a completely different system.
so back to the drawing board for me..... i'm gonna make sure i don't have any fuel pressure loss when i accelerate hard now, also i may attempt and clean my maf w/ electronics solvent cleaner. maybe from sitting for so long it accumulated crap on it, maybe the oil from the k&n filters in my airbox got on it...i donno...

cam-

Thats still my guess.

I wouldn't do that they are fersnickity little buggers and you might wreck it. Just unplug it and let the car go to limp mode. It will run pretty decent even without the MAF so you can easilly determine if its euchred by just unplugging it.

Blkdth87

ok, well checked the fuel pressure while powerbraking the car today, it's hesitating, and the fuel pressure jumps to 60, so it's not fuel. anyone think my k/n filters may have fkd up my maf? and what i was thinking was putting my maf in another car and testing it out. but i don't know anyone anymore around here that drives an ls1 car.....

dingle

As Cam said in here earlier, you can just unplug the MAF and the car should run well enough for you to tell if that's the problem or not. A lot of folks on here have K&N filters.

Blkdth87

unfortunately the weather here hasn't permitted me to do any more testing, we got some snowwwwww..... so hopefully tommarow will be better, i'll try it out. hopefully thats the problem.

cam-

For what its worth the first time I had a MAF go on a TPI car you had to floor it just to keep it moving. I was totally fuelly inept at that time circa 1990 or so and I thought the engine was cooked for it to run so bad. I was halfway up north three hr drive so kept going. Local mech up there unplugged it and yahoo she ran aces after that

Blkdth87

i remember those damn tpi's....i just wasn't sure if this would work the same way.... well anyways, i'm gonna take the car to work tomorrow so i'll disconnect it before i leave home. hope it works.

Blkdth87

ok, so i disconnected the maf sensor, it feels the same off the line, but somewhat feels better on the parkway when i mash the pedal down at 45/55 mph. its still a dog off the line though....

Blkdth87

how sensitive are the ls1 knock sensors? i was thinking, i do have alittle ypipe rattle on the frame rail, maybe thats the reason..... what u people think?

cam-

If its Knock or any other engine management troubles you will get codes for it. Check them if you have a tuner/scanner whatever or get them checked

MrDude_1

fuel pressure should be 55psi at idle.. 55psi at WOT...ect... it should NOT be referenced by the manifold... rather, it should be referenced by the atmosphere

dingle

You need to get a scanner on this and see what is going on.

Blkdth87

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Blkdth87

Got an update. kinda my fk up really. i never hooked up the brake signal wire.
hooked that up and the car flies

can't power brake it though, anyone else have this problem? the brake signal wire should have 12v when off the brake, and should go open when on the brake. so i hooked it up to my brake pedal switch. should i just put a bypass switch and turn it on whenever i feel like lighting em up?