m30 problems

[stinkydriverx]

hey guys, just looking for some advice before I tear into the car to find out whats going on. I have about 600 miles on my swap and everything has been good. Last night the check engine came on when I was driving it.. So I stomp tested it and nothing, it says it had no codes stored.... So that was confusing. The car still has the check engine light come on when I start it.. but here are the symptoms:

So it starts, and idles really rough. The best I can describe it is, it sounds like its running a 292 cam or something knarly.. Second... Anytime I apply more than a quarter throttle it just feels like its missing really bad.

So I have two thoughtssss... Vacuum leak. or fuel pump/filter....
What do you guys think? engine is a b35

[Lurker27]

My bet is misadjusted throttle switch not triggering back to idle

[Lee Harvey]

vacuum leak. the cammed sound, the rough idle, the way the throttle behaves, all classic vacuum leak symptoms. Get to spraying with some started fluid

[stinkydriverx]

The weird thing is I can hear the vacuum leak. But I can not find it for the life of me. I have sprayed starter fluid everywhere in the engine bay... haha. So im going to smoke test it and see what that results in. Any other suggestions?

[Jean]

What wiring harness are you using? Make sure each injector is firing, if it's the e32/e34 harness, remove the top cover and seat each injector plug individually to make sure it's on.

Check the TPS / AFM as well.

[stinkydriverx]

I'm using a late model e30 harness. My problem is I had peerless do the wiring. So I have no idea what the hell is going on with any of that. I can still hear the vacuum leak, I found out there was one on he valve in between the intake and evap stuff. so I got a new one. But I doubt that would cause rough running.
You can also tell its running ungodly rich. I know vacuum leaks cause a car to run lean usually, correct? So next is to switch out the afm, and the 02 sensor, and that evap valve. See how it goes from there.
If any one else has ideas, they are still appreciated.

[yert315]

check your cps wire. Sometimes those get frayed on the pulleys.

[Bearmw]

Go back to basics and start with a compression test.

[603Racing]

A disconnect or short in the wiring to the airflow sensor(meter) could cause that symptom, but it wouldn't sound like a vacuum leak. My m30 idles rough and misses if the airflow sensor is unplugged, as do most motors.

+1 on the compression test.