Let sleeping dogs lay

[acspecialists]

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So after finding and repairing a bunch of corrosion on my daughters 740i I figured I would take a peek at my car. It was running fine with no problems but I just could not help myself.

So I pulled the E-box apart in the engine compartment. I found the same corrosion as her car just not as bad. I pulled the relys apart and of course have them face up without a weather tight connection they were all rusty. So I set about cleaning all of the plugs and DME, TCM sockets. I was pretty proud of myself for getting things cleaned up. I used a high alkaline cleaner to remove the corrosion and the electrical cleaner to wash it out. A little blow out with air and plug everything back in. Go to start up the car and it barely runs so I shut it off.

I must admit that i figured I had a 50/50 chance of screwing things up. So I pulled everything apart and cleaned it again. An extra blow with air and some heat to make sure everything was nice and dry. My next attempt and the car would not even crank. The gauges and lights were going crazy. I disconnected the battery for 30min and tried again. The car finally started again after a few tries but it was surging wildly and would not respond to the throttle. Time for INPA.

I had throttle pot mismatch codes and pedal pot mismatch codes, mostly. I had a bunch of other codes that would come and go as I cleared them and retry running the car. In the end I thought I killed the DME. Everyone know how much fun it is to replace one of those on a BMW. I had to leave to try and land a shipping job. Meanwhile I tracked down a pick and pull with three e38's. I went in and grabbed a DME that was laying on the ground under a car, a throttle body and snagged a newer style pedal out of and X5. I was ready to go with a box full of parts.

I came home and plugged in my DME again and gave it a go, nothing! I turned off the key and back on, waited a few seconds and tried again. Varoom! The car ran just fine, I'll take it for a drive today. So the moral of the story is let the car fail and then fix it. Every heard that one before?

[Aitch]

So the moral of the story is let the car fail and then fix it. Every heard that one before?

That's what my mechanic has recommended regarding servicing the transmission. Wait until it acts up to swap the filter and fluid.

[Mayorchuck]

Did you disconnect the battery before you started unplugging things?

[georgebest]

So the moral of the story is let the car fail and then fix it. Every heard that one before?

I should print this on the wall of my garage

[DorinDav]

I feel your pain.

-guy who swapped CCV plate for no reason

[acspecialists]

MAYORCHUCK,
No I did not disconnect the battery. I have lost count of how many times I disconnected the DME and TCU in may car and my daughters. Probably bad practice but as of now both cars are running.

[franco90]

MAYORCHUCK,
No I did not disconnect the battery. I have lost count of how many times I disconnected the DME and TCU in may car and my daughters. Probably bad practice but as of now both cars are running.

you know all the water might be coming from the thermostat check the wires to see if the wires are bringing the antifreeze in the box. trust me I know . also under the EBOX there is more fuses you might want to check those out, there is a 25 amp fuse or 30 amp dont remember that blew and cost me $500 to tow it and also the famous trans failsafe came on. car would NOT Start It took me weeks and found that damn fuse.

heads up