Vibration Causing Limp Home Condition
 

I'm experiencing a problem where the ECM drops into limp home mode immediately after going over a very rough road, or a pothole. Shutting the engine down and restarting makes the problem go away.

I've been pretty sick, and haven't gotten around to lower the ECM and taking a look to make sure everything is ok (I'm running an Ostrich on the vehicle with a Moates prom adapter and ZIF socket, so there are several sources for a possible bad connection). Assuming I don't find anything that looks like a potential problem, I'll be swapping the ECM out and seeing if the problem comes back.

I was curious to know if anyone has seen a similar scenario before, this is the first time I've seen something like this. This is a 730 ECM by the way.

Re: Vibration Causing Limp Home Condition
 

I've had retention issues with ZIF sockets and finally stopped using them. No fun when the PROM falls out or comes loose in rush hour traffic on the highway.

RBob.

Re: Vibration Causing Limp Home Condition
 

Ya, had it do it to me more then once, lights flashing on the dash whent into limp home mode.
Seamed like the cable was not making good contact in the ZIF socket for some reson.
I took out the ZIF socket out, all was good again.

Re: Vibration Causing Limp Home Condition
 

Me too. the ZIF was the issue. Now I never knew if it was the ZIF to socket or the ZIF to eprom. maybe a ZIF soldered in would be better? I piggy backed mine.

Re: Vibration Causing Limp Home Condition
 

I don't use ZIF chips, but after using a regular chip a coulpe hundred times it wore out and fell out on me a couple times before I threw it out, went into limp home mode.

Re: Vibration Causing Limp Home Condition
 

I had the main board come loose inside the stock ECM on my 91 Z/28.

It would randomly go in and out of limp home mode usually in conjunction with a bump or a hard corner.

It was stock enough that limp mode worked well enough that the only way to tell was that the speedometer would stop working and the idle would go way up. A new ECM fixed the problem.

Re: Vibration Causing Limp Home Condition
 

I didn't know so many people have had issues with ZIF sockets. I'll be pulling it out and do some driving around without it and see if the problem dissapears.

I'll post an update later when I get a chance to tinker with it.

Re: Vibration Causing Limp Home Condition
 

Update:

The ZIF seemed to be holding the emulator connector very well, and seemed securely mounted on the Moates prom adapter as well. I pulled it off anyway, and mounted the emulator connector directly into the Moates adapter. I drove around some rough roads, purposely hitting potholes and such, without any limp home issues. Seems like the ZIF socket may have been the problem. I'd have to do more driving to know for sure, since the problem didn't happen everytime I drove over a pothole before, it seemed a bit random.

On a side note, I noticed the ECM itself was not warm at all after driving for 25 minutes or so. Aren't they supposed to be warm while operating?

I remember the 730 ECM I had in the car a few months ago staying warm to the touch when the engine was running (that ECM failed and was replaced a couple of months ago).