TURBO 3.4DOHC PROBLEMS-WTF NO FMU

[dohc v6]

How would i know that? Is there some way I can test. i did run a fuel tester on the car and it ran at 40lbs and then went up with boost,up till 90lbs and then it hit the 3lb mark and went down and then shot back up and it goes back and forth. I just finished replacing the plugs, well see what happens.

[Nick1234]

i have no clue how to find out. the reason i bring it up is because you said it was like it hit a rev limiter. in my lumina, if i add a little more boost, it seems to do the same thing.

[dohc v6]

Well it probably is doing that. I just ran the car and no go. PLugs did not do a thing. What would cause the car to not dump fuel?

[skalor]

The first thing I would do is swap on some stock GM coils and get rids of the MSD ones. I don't know the specifics of your setup, but are you running a draw-though MAF??

 

EDIT: I see your running a blow-through MAF. What kind of MAF is that??

[dohc v6]

Its not spark, its gotta be fuel. The maf I am running is the stock maf with lt1 end pieces.

[dohc v6]

So i disconnect the FMU and it works 5 psi on medium throttle and green on the A/F gauge. I completly disconnect the fmu vacuum source and now the car is fucking fast as shit. I might have a small vacuum leak but it does not do the jerking thing anymore. Maybe the FMU was dumping too much fuel?

[skalor]

I say forget about the FMU, put on bigger injectors, and tune it the right way.

[dohc v6]

The only way to tune is going to be with a standalone system. I am going to change the FMU to a 4.1 instead of 12.1. I need a little more fuel but not 12.1 its just too much fuel. I need to do a little maintence tomorrow, and its very addicting. It wants to go faster and faster. I already smoked a 325 i twin turbp.

[Chancho]

nice, a 335i tt isnt that a 13second car, and u pulled him, that car must be FAST

[Psych0matt]

well, if a stock 3.4 can pull a mid 15, a nice turbo one like this could easily be in the 13s

[Chancho]

yea but to smoke means beat with great force (the new chancho dictionary) therefore one can infer that this turbo 3.4 could possibly run 12's

im just talking out of my ass, time for bed

[dohc v6]

UMM not likly. I would be happy to run a mid 14.

[Andrew]

i bet at least mid 13's.

[Psych0matt]

UMM not likly. I would be happy to run a mid 14.

 

that would be doable without a turbo, since stock (on a brand new or extremely well running motor) could run low 15s with a good driver. I'd be willing to bed you're pushing somewhere around 260hp or so (very open guess, since I have no idea your mods/tuning), and would run mid 13's all day.

[dohc v6]

Here is what I have or will have done to the car.

hyperutectic pistions

bored 20 over

light weight lifters

fully balanced crank

clevite 77 bearings

crom moly seal power rings

srp rod bolts

casting flash removed from entire engine

180 stat

msd coils

magnacore wires

high volume oil pump with a high volume spring and blueprinted

t3/t4 turbo 60 trim

k and n filter

 

thats really it

 

I want to do in the very near future

 

fully 3" exhasut with magnaflow muffs and resonators

standalone fuel mag

 

 

[dohc v6]

Here you go

[BXX]

Your hitting 80psi of fuel pressure!!!! There is your problem. At 80psi your lucky that the pintle can reseat in time. I think only Lucas and MSD Race injectors with proper injector drivers (i.e. standalone EMU) can handle that kinda fuel pressure...

[skalor]

The only way to tune is going to be with a standalone system. I am going to change the FMU to a 4.1 instead of 12.1. I need a little more fuel but not 12.1 its just too much fuel. I need to do a little maintence tomorrow, and its very addicting. It wants to go faster and faster. I already smoked a 325 i twin turbp.

 

I would use a newer OBDII LQ1 harness/PCM and buy HP Tuners. It's going to be cheaper than a stand alone and I have never seen a stand alone system that is better than GM OBDII PCMs.

[intern8tion9l]

platinums are no good under boost. it tends to blow the electrodes off

[per0781]

get a real tune and go from there. did you get an upgraded fuel pump?

[19Cutlass94]

Platnium plugs dont last under high cylinder pressures. Doesnt matter if its N/A or turbo.

[dohc v6]

I got rid of them. I put regular r42ltsm plugs in, seems to work a little better. I do have a new fuel pump. Its a walbro hp255

[dohc v6]

Ok, I get boost, but my car still seems to take about 10-13 sec to cranks before it starts. I replaced the FPR and disconnected the FMU, new fuel pump and it holds a steady of 40 psi for a good while.