It just never ends. 98 Mazda 626 GF 2L. It cranks great, but there's no spark at any of the plugs and I can't connect to the ECU. Coil pack is new, I've driven it maybe five times since I replaced it. I've also been having a low voltage from the alternator for a while, about 13.75v, but can't so far find any problem with the alternator.
I'm kinda freakin out, thinking maybe the ECU has given up the ghost.
This is somewhere between a rant and wanting to have someone tell me that's it's likely not an ECU problem... arg!!!
I know I need to check the pins coming into the coil from the ecu to see if a signal is coming in or not... just afraid of what the results will be...
EDIT May 31st, 2016
So I go out today to try and make some progress on this problem, and what happens? The car starts right up and I am able to connect to the ECU / PCM with no problem.
When I connected I got a 0113 DTC. I had this error a few months ago, but I cleared it and it didn't come back. This time I cleared it, ran a KOEO test and it came back. Cleared it and ran a KOER test and it came back. This is the list of causes ( also for a few other DTCs ):
So I went to look at the IAT connector and found this:
The wire seems to be made of four strands, two of which are broken and probably making intermittent contact.
I'm going to go look for a good connector from a junk yard and splice it in, however, I'm not sure this is really the source of the problem for a few reasons. If I completely disconnect the IAT sensor the car starts up just fine, so I don't think that frayed wire would cause an intermittent ECU problem, would it? Looking at "Cranks Normally But Will Not Start" in the troubleshooting section of the WSM it does mention a few problems where a short to ground can be a cause, like with VREF and an "IG" line from the DLC, but I don't have a short to ground here, I've got a partial open.
The other thing that's making me suspicious is an aftermarket keypad immobilizer that's been installed in addition to the factory key chip immobilizer. I remember the previous owner saying he had disabled it because it had been causing him problems, however it is still physically wired into the system under the dash ( it's a nasty rat's nest of spliced wires under there ) and I'm wondering if maybe it's haunting me from the grave so to speak.
I'm still feeling like this might be related to the alternator problem since I think the voltage regulation on this model is done by the ECU.
EDIT June 2nd, 2016
So I spliced in the new IAT connector, cleared the codes, ran the KOEO and KOER self tests, and so far so good. Not sure what to make of it. I was thinking of pulling the ECU out to visually inspect it, but maybe I'll just keep an eye on things in the mean time and see what happens.