Help...electrical gremlin!

[Topless]

HI all...
Ok, my 92 vette is possesed. I was driving back from a road trip today, and every once and a while the engine would cut out momentarily. (usually when accompanied by a bump in the road) The Service Engine Soon light would flash too. Then in an instant, it would be back to normal.

Variations....
After I fueled up, when I strarted it, the Service ASR light and the Service Engine Soon lights came on. This was accompanied by high idle (1,500 rpm's) that would not drop. When I shut it off for a couple seconds and then restarted, it was normal (idle and lights).

I hit a bump once, and the cutting out happened as before, but this time the Service ASR light came on, and stayed on.

When I got closer to home, I hit a bump, and the engine went into a seizure. The RPM's were jumping from 0 to 2000 (where I had been running) and the car surged like crazy. I put in the clutch, and the car about died. I was able to get it to stop by tapping the brakes (hard) and that jerked the whole thing back together again.

I did blow a upper coolant hose a couple weeks ago, and that did get the front of the engine fairly wet. Other than that, I tagged the "x" brace/frame stffener on some road construction on the way out to Utah from Denver.

Oh, and other little electrical this have appeared about the same time.
1. I can not get the AC to change temps. I adjust the temp, but it still blows the same temp.
2. The AC fan will not change speed.

Someone please help me remove the electrical demons in my vette.

-Mike

 

[Ken]

I did blow a upper coolant hose a couple weeks ago

Soiunds like it might be Opti-Spark replacement time, what do you think people? I would definitely say it sounds electrical though... Maybe you might want to check the coil and/or ignition module too.

 

[Topless]

ok...an update...
I checked for codes...nothing.

I ran the engine, and looked for loose wires...nothing.

I tapped the ECM while the engine was running, and it stumbled.

I tapped it repeatedly, and the engine shut off.

Short in the ECM? Fixable? New ECM? Would hitting a road resurfacing seam (they did not slope the cut to the existing surface) at 65 mph damage the ECM?

Thanks

-Mike

ps.. Fan speed has returned to normal.

 

[Ken]

If it isn't the OptiSpark...

In "Phase I" of my engine project, a brand-new ECM was bad when I got it. Chris (69MyWay) found the air intake temperature was reading a minus 40 degrees last year when we got together in Bowling Green, and the ambient temperature that day was around ninety degrees... above zero! No wonder it wouldn't run right said he. :L

It's certainly worth checking out, the cost is minimal compared to some other things, like LABOR CHARGES. This you can easily do yourself.

_ken

 

[Topless]

Uh, ok.....how would I go about this?
;stupid

I thought this would be a trip to the dealer.

Thanks
-Mike

 

[Robertwav1]

Make sure the numbers match on the ECM replacement. Disconnect the negetive battery cable, hook it up and reconnect the cable.