cole737

I fixed the program problems, running too lean after injector change. Runs good when first started for the day. But engine surges and stalls if you shut down and restart after sitting. Once I get driving it fixes itself. Any ideas, I'm thinking Control Module. What is the test procedure?

Thanks in advance, Cole


30# injectors, Adjustable airomotive regulator, 58mm throttle body

Jlo

check the fuel pressure, it could be your fuel pump going bad..

Injuneer

Yes, check the fuel pressure. The Aeromotive AFPR is extremley unreliable.

cole737

I checked pressure. It was 43.5 at idle with vaccum removed. I guess it could be an intermitant failure, that I didn't catch. I'll check again while driving, start up and shut down. Any other ideas? I'm out of town until Saturday, so if anything comes to mind. Thanks for your input, very much appreciated.

Cole

Injuneer

What do you have done to the engine that requires 30 #/HR injectors, an AFPR and a 58mm throttle body. You wouldn't put those parts on a stock engine, so list ALL the engine mods.

Who tuned it? How big is the cam?

henryz28

Yes we need to know all mods and how it was tuned to help point you in the right direction. Is there any codes? I had my water temp sensor go out and cause my car to surge badly but that would turn on the SES light.

cole737

Maybe I went a little overboard with bolt-ons. It still has stock cam, ect.. Planning on a total rebuild next summer, 383, hot cam ect.. The engine ran good with these bolt-ons. But then started surging a while back, so I changed the regulator. That didn't seem to help, so I had Solomon help me with a tune. The motor screams, but still surges and stalls after shutdown and startup. No codes noted. When I get home from work Saturday I'll do further fuel pressure testing.

Thanks, Cole

cole737

I checked pressure with engine surging. Pressure only change 1psi durring surging. So I'm still looking for problem.

Thanks, Cole

Injuneer

So.... if I understand correctly.... you have a totally stock engine, with 30 #/HR injectors, a 58mm throttle body, and an AFPR. Might want to put the stock throttle body back on it.

When you installed the 58mm throttle body, did you first check the idle RPM (using a scanner, not the tach, which usually reads high), the IAC counts and the TPS voltage? Is the intake manifold opened up for the 58mm TB?

cole737

Some of the stock injectors were bad, so I thought to upsize. I did port out the stock manifold for the 58mm throttle body. The thing is, it ran good untill recently. Then started surging after warm up. I thought I should swap Ignition control module and go with after market coil. What do you think? Sorry, it takes me so long to reply sometimes, but they are killing me at work. I guess I should consider myself lucky to have such problems.


Thanks, Cole