Who wants to take a stab at a doosey?

[Low Budget]

Anyone who really knows me can tell you I'm not afraid to admit when I do questionable things. That said...you may call me dumb ass!

Background:
After putting my new engine back in I noticed the check engine light never lit. There was voltage at the ALCL pin for this function, so I thought the bulb was shot. Weeks later, during what turned out to be a dead shorted battery, we (I'll keep the other parties name out of it.) decided we were going to supply some vital circuits power by back feeding them from other circuits at the fuse block. (We had no power at the solenoid for the starter. We thought we had some weird problem.) During this "questionable act", the check engine light flickered, came on bright, flickered...We never did figure out the problem. I thought we had eliminated the battery as the problem, but that was it anyway. Cost me $145 to let a shop good with electrical stuff figure it out and sell me a new battery! @#%$@#!

Problem:
My EGR is being told to open all the time. Even at idle. I replaced the solenoid, no change. The ecm shows the code for EGR circuit, and the check engine light is on all the time. Sometimes it dims a bit, but never goes out. Now I drive with the EGR vacuum line disconnected and plugged to keep it running at idle. Please Help. Bad ECM???

Thanks, Jeff

 

[topfuel]

trying to understand better

Which "vital circuits" did you feed power to and where did you
get the power from, if the battery was dead?

ECM inputs operate on a 5v reference signal, maybe 12v was
enough to zap the ECM...

 

[machinegun]

I had a problem somewhat similar to yours. I had a check engine light all the time and found codes 13 14 15 and 44 I think. Really strange to have coolant circuit high and low. So I replaced the sensor to no avail. Still got 13 14 15. Checked voltage to the hot side and all was good. Check resistance to ECM plug and all was good. Direct scan was reading really weird temps. I then started getting an EGR solenoid issue. I finally replaced the ECM with a known good one and all my problems went away. I would make sure there are no circuits going to the ECM grounded and then I would try with a known good ECM.

 

[Low Budget]

The battery wasn't dead, it was shorted internally. It showed the proper voltage when checked, it just had no capacity for amp draw. This may have allowed plenty of power to short things out crossing circuits though.

I can't recall exactly to where we fed the power. We took power from the fuse block at one of the posts labeled bat or battery. We were trying to see if we had a bad fuseable link, bad ground or maybe a bad ignition switch. The latter is why we started trying to "hot wire" the starter solenoid.

One thing I wonder is this. Why was my SES light not working in the first place? I can easily see how shorting the ecm could cause it to be on all the time now, but do ecm's ever go bad where all they do wrong is not activate the ses light when required?

Live and learn. I can wire a house and all kinds of industrial single and 3 phase equipment, but D/C kicks my butt!

 

[crusacargen]

I have the same problem as far as the SES light not coming on at all, one day accidentally engine caught a small fire then miraculously the check engine light works, so I buy a code reader, right before I plug it in the SES light stops working, I am still trying to figure this out, my car has not started yet because of this and the coolant temp ligh is not working. any ideas anyone?