Subject: Re: One Dead ECM by bogus on 2010/12/14 2:47:42
Quote:
Pcolt94 wrote: Just a few thoughts
Having worked 35+ years in commercial and military electronics I have seen, repaired and supported a lot of electronics not to mention automotive. Sometimes it's tough to fix a system with loops, feedback and bus talk, when components seem to check good individually.
Getting the ECM checked by a dealer might, or might not tell you what you are looking for. The thought is definitely positive to yield the facts or truth. One better is to try the ECM in another corvette of same vintage. There nothing like a functional test for best verification. Sometimes simulated tests just dont show the real story.
I have seen the external pins of a connector open up electrically to its internal connection within the box. This can happen under the weight, load, pressure or torque produced by the external connector on the connector of the box. I'm basically saying that this condition may not exist when it is placed on a test bench and the connectors are just laying there nicely. Just a possibility.
If you have an indication on the dash (SES light) or another condition where an assistant can look at while you move or wiggle connectors and harness, something might show up. Having put another ECM in your vette and getting it started having normal conditions sure does look like you had a bad ECM. I would then put the original ECM back in and check results. Finally I would try if possible the suspect ECM in another car. Having cross checked and double checked in this way then might give you a warm feeling of what you really have and then you can go back to SIA with some very confident facts.
Of course this is my approach and just suggestions. Depending on whether you can come up with another vette may limit doing these things but might just give you some new thoughts on the situation and you approach.
I know what you mean. I have considered that a pin might just be compressed... but that would mean TWO pins, that do the EXACT same thing, are compressed! The odds are staggering.
These cars do not bus their signals, it's all direct data, so none of that loop back crap to worry about.
The Serial Data Line has to pins, which means two UARTS, sharing a common line to two more pins and two more UARTS on the CCM. Both lines toned out perfectly - and trust me, I do NOT want to have to go back into the fucking dash to confirm his. The CCM is behind the radio and is an absolute bitch to get out. Sorry, I just don't bend that way.
The next time I do something stupid like this is if I am taking the entire dash out and am in the process of installing an all new harness, to better integrate an LSx engine controller in with.