I have an unusual no start with my '94 Transam.
It has only 80K, is all stock and in good tune.
Car ran great till I hit exactly 90 MPH then it died but imediatly restarted. This happened 3 times at the same speed. During this time I could downshift and run it up to near redline without a miss.
Since the last trip to 90 it will not fire and has no spark.
I checked the coil with an ohm meter and it shows fine across high and low sides. I then replaced the opti, but still no spark.
I have proper voltage to the coil. Other PCM functions seem fine including injector pulse.
What else could I try???
Is seems peculiar to me that it only happened at a particular speed.
I am really tired of seeing my toy on jackstands.
Any help would be appriciated.
Wes

 

You say you checked the coil with a meter, but did you check to see if spark was coming out of the coil wire. It could be bad and still meter ok (but not meter bad and be ok ).

 

yes, I checked for spark at the coil.
I even checked the coil wire for continuity.

 

Confusing post.... when you checked the coil, was there spark, or wasn't there? Since you say you have "no spark", it would appear you checked the resistance and it was OK, but there is no spark... but its not clear from your posts.

 

You have to tell what the result was when you checked for spark from the coil.

 

If the coil is fully functional but the spark isn't getting to the plugs, it might be the rotor. Just one possibility.

 

Sorry I was not more clear,
There is no spark from the coil. The coil and coil wire test fine. I also have proper voltage to the + side of the coil. I had no spark to the plugs, or out of the coil before or after I put in the new distributor assembly. Obviously the old distributor was not at fault but it seemed like a good place to start eliminating problems since thy are so prone to failure. The new distributor came assembled with new cap and rotor. I am questioning if there could be some thing with the PCM, wiring, or possibly a previously installed alarm system that could be shutting it down. I have had the car to + 90 MPH before with no problems, but once it started shutting down @ 90, it did it every time. I am not aware of any alarm system on the car other that the factory VATS system. I did have trouble with that a few months ago, but I bypassed it with a resistor under the dash and have had no problems with it since. When I did have trouble with the vats, it just would not crank. As I understand, the vats will only prevent cranking and it can disable the injector pulse. I have no problems with either one of these.

 

Did you test the Ignition control module? its kinda flat and it mounts with the coil

 

I'd suspect the coil. Either swap it with a known good one or replace it. They're about $50 new. The ICM is over $100.

 

The cutting out at 90mph seems strange. Did you check to see if the ICM is getting a signal from the opti??

http://shbox.com/1/4th_gen_tech2.html#opti_test

 

I am trying this proceedure now.
thanks

 

It's not going to run at all without that signal. It would be kind of hard to check at 90 MPH.

 

check the fuse for the icm first, do you have power to the icm?