Originally Posted by
Durdan
thats odd bc out of the 100+ cars i have installed walbros i have never run into that issue.
and nora, sure you can up your fuel pressure to get more fuel... but at the expense of your injectors over driving and dying. why do you suppose the FMU went out of style like heroin and david lee roth?
the proper way to adjust fuel is through duty cycle. forcing more fuel through is not good. as far as vacuum, the reason for it is that under negative load (vacuum) the fuel pressure is lower. under WOT, the fuel pressure raises. additionally, under boost, the fuel pressure rises 1psi per lb of boost. FMU's totally negate this and burn up injectors.
for example:
45 psi fuel pressure static (no vacuum/no boost)
on factory regulator:
45psi + 15psi boost = 60psi of fuel pressure... cool, no biggie
on just an 8:1 FMU (considered low ratio):
45psi + 15psi boost = 165psi of fuel pressure [45 + (15x8 )]
and there are FMU's that go as high as 14:1!! scary stuff!! this is how turbo kits used to come in the late 90's with an additional fuel pump inline. no ecu controls, no tuning... just rediculous fuel pressure.
but back to original, the jump from 38psi to 45psi at idle will richen the setup, but not to the point that you would have some crazy rich condition. especially if your pressure is beind raised via a vacuum leak. in fact, the vac leak will cause more of a lean condition than the 7psi increase in fuel pressure will cause a rich condition.. if that makes any sense.
no wonder all of the "old school" guys say turboing a car is so dangerous and costly and breaks shit. I couldn't imagine ever thinking that was really a good idea. 165+ psi. Damn. my idea was more like adding another 10-20, not 110 to 120. shit.
To the OP. Have you tried spraying some carb cleaner/starter fluid around your engine bay to try to find any vacuum leaks?
Also, double check your timing. You might have it right, but 180 off.
check for leaks, and make sure things are plugged up nice and time. The MAF plug tends to get loose. That might cause this problem.... maybe...
You said it was firing every other time? as in enough to check the motor running? or only if the starter is turning?
While you're at it, try to go through the process of getting the codes off of the ECU. It might have something of value stored in there...
Once you've done all of that. and we still can't figure anything out.
I say pull your distributor and reset your timing the right way, just to make sure that isn't the problem.