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02/13/10 - ECU Issues and waterpump leak

We installed the ECU to do some initial testing on it on friday.  Something was certainly awry though.  The main relays were not turning on or off, the polarity of the lowside drivers also seemed incorrect.  I spent a long time tying to figure out what was going on, all to no avail.  There was no spark at the plugs, either.  To top it off, as soon as we added coolant, a huge leak was detected on the front of the motor.

The next day I decided to address the leak.  I got up at 8 am and started tearing the front of the motor apart.  Once the timing cover was off, it was clear where the leak was coming from.  The slot on the water pump extended into the pump cavity.  The oem pump didn't have a slot.

It sucked that I had to remove the timing belt to pull the pump off, but I feel like I did it in a TIMELY (har har har) fashion.  Matt (lowlyoilburner) stopped by and help me weld up the slot.  (I thought about trying it myself, but I was too worried about damaging an semi-hard-to-get part.  After it was welded I block sanded it and the result:

I then put the water pump back on.  Went fairly smoothly.  Nice to know I could probably change a timing belt in an hour or so on this car...

Over the course of the next few weeks I did a lot of diagnosis on the ECU.  This involved bench testing, in car testing, harness checking, etc etc.

Ultimately I diagnosed the problem as an issue with the internal main relay circuit (AEM's fault), as well as a very small issue with the ignition circuit (my fault).  More on the ecu later...


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