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View Full Version : help me ale my vr-4


mr. twin turbo
08-28-2007, 08:43 PM
ok heres the problem, my car starts, nut it doesnt run. now on the mechanical side i am an expert, but when it comes to electronics on a car and troubleshooting them, i suxors. anywho, heres what happens:

i jump in the car, clutch to the floor, turn the key, engine turns over and starts no prob. by default the ecu sets the car into a mid throttle position for startup, so the engine revs to about 2000 rpm. about 3-5 seconds after turning the engine on the engine shuts off. if you gas the car within these first 3-5 seconds she will rev up no problem, but as soon as that 3-5 sec is over the ignition seems to cut. my first thought was the ecu, so i ripped it out. checked all the caps, and its all ok, no corrosion, fraying, bent / broken pins, not even a spec of dust. so i assume that my ecu is a ok. my next thought is its either a vac or a boost leak. i test all ic pipes for leaks. none found. i sprayed the ic with a mild detergent and soap mix to see if it would make bubbles, ie. a leak. nothing. i hooked up my new boost controoler, and on startup i make 20 hg / in. which is proper vac. however under throttle i make exactly 0.00 psi. no matter if i rev to 2000 or 7000rpm. so where this lack of boost is, idk. i also checked all of my vac lines (which are all new) and i have found nothing) my only other thought has been that its a bad maf. i switched to a 3" gm maf with a dsm / 3s maf-translator. i played w the base settings to see if it was simply to lean or rich at idle and that was killing it, but no luck. plus it will die at high rpms also.


heres whats been done since the last time it ran:

crank cut and oversized bearings installed.
aluminum fly
6 puck clutch
hybrid turbo setup ; mhi 9b in the rear, mhi evo3 16g in the front
fmic
3" gm maf
dsm / 3s maf translator
egr removed

anyone have any ideas, much appreciated.

auditech79
08-31-2007, 02:38 PM
So it runs for a few seconds then just turns off, or it studders and dies?
Also you don't need a bigger MAF un-less you're upgrading the fuel delivery system, take that out, clean your old one with some electrical cleaner and put that one back in and see what happens.
Also get the fault codes checked, that should be the first thing you should do when diagnosing and engine related concern.

mr. twin turbo
08-31-2007, 02:54 PM
^^ thanks for the tech 101 but i have no cel codes, its not a bigger maf im running, its a different setup. my oem maf runs pre turbo, thus not getting the most accurate reading, now its post turbos. i threw in the old maf, just pluged in not connectind to plumbing, and the car runs, so i have to test this maf, its either a bad maf or a bad translator, the translators new so if thats bad then were gonna have some problems with a certain company, lol, but if its the maf the kid i bought it off of already said hed refund me.

auditech79
08-31-2007, 09:55 PM
Yeah my money is on the MAF, if you un-plug the MAF (just the electrical part) and you can run the engine and drive it around its most definately the MAF sensor. Its not gonna run like a champ though with the MAF not connected.