Quote:
Originally Posted by Marc Haibeck
Hi Joe,
If the cooling fans turn on before the engine is started, the program in the ECM is not running and the ECM is in backup mode. The most common cause in your situation is that the calibration chip is not plugged in to the ECM.
The CCM will flag a serial data error if there is no data from the ECM (program not running) or if the data is in the wrong format. The serial data format may be wrong if there is a chip in the ECM but it is the incorrect model year for the car.
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One of the first things I did was reseat all the connectors and the chip. Same result. The chip I used in the spare ECM was the one I pulled from my personal one before I sent it out . That's why I asked you before if possibly my chips could be corrupted (unlikely I agree, but not out of the realm of possiblities). I was originally thinking it's either 1)comm line between the ECM and CCM is not good (either the pins at the connector or the actual wire) 2) bad CCM 3) corrupted chips.
I do have your chip that I haven't installed yet, I could test with that and see what happens. What would happen putting in without the ported plenum and injector housing? Car would run rich?
I can also try reseating the chips on the holder too (I've seen instances in electronics where a little bit of corrosion forms on the chip legs. Sometimes reseating fixes it or if it's bad, some very fine sandpaper will do the trick). I'll dig around to see where the comm line goes to. I'm just worried my FSM is not accurate. I've noticed minor discrepancies in mine compared to other 1990 FSM's (Like B15 not being used).