02-14-2010, 07:59 PM
Join Date: Aug 2009
Location: Las vegas
Total Cats: 0
cant go turbo until this is fixed help
i tried posting this at miata.net but no one is helping out?
I'm trying to help a friend diagnose his no start issue on his 92 1.6L and I am leaning towards a bad PCM. I have read the No-start troubleshooting thread and the only thing I haven't checked is having power at the "X" terminal on the ecu. I have no idea which pin it is as I don't have access to a factory service manual or enthusiast manual unless I missed an online version. If I did, direct me in the right direct please! lol. Anyway, here is the rundown on what the car is doing and what I have done so far in my attempts to resolve the issue. Let me know what you guys think. In short, the injectors don't seem to be firing.
-Fuel pressure is around 40psi while cranking so the pump is working(Confirmed via inline gauge)
-All 4 spark plugs are firing (The car will attempt to start when given some starting fluid)
-Compression checks out
-Fuel Inj relay is working (I removed the cover and watched it operate correctly and even activated it by hand) I also noticed that the IACV clicks when the relay engages. Is that normal?
-I am getting no pulse on the injectors (Confirmed via noids/test light)
-CEL showed code 3
-I pulled the PCM and visually inspected it, but did not find any definitive burn marks. I assume there could still be an internal malfunction?
So as you can see, it appears I have narrowed it down to the PCM unless there is something else that controls/influences the injectors??? The IACV I believe is also acting up as the car idled at 1000rpm before it stopped running altogether. Could a bad IACV kill the PCM or inhibit starts? I come from working on mitsubishi's and on some cars a bad IACV can kill the PCM. Is that something to worry about in the miata circuitry? I'd hate to try another ecu only to kill it. Thanks for the help!