Hi Guys, have a -88 Iroc Z-28 with 305 TPI and manual gearbox, only around 33000 miles on the odo. But a couple of weeks ago something strange appeared while driving.

Sometimes when I press the throttle it feels like the engines timing sets to be very early, so early that it actually brakes it self, when I ease of from the gaspedal it finds the right timing again. This problem is not always appearing, it comes and goes during the ride. Are there any vacuum sensor that could be the problem or what do you guys say ?

Please answer to bo@neckmike.com it is not everyday I will have the time to go into the forum.

Best Regards from Sweden !

 

It won't be timming as I suspect when you push the gaspedal it will at some point go off vacuum advance. I'd suggest check the timing at idle, and also look at the distributor. There is a pickup coil that sets center of th rotor that could be causing problem. There also is an ignition module (I believe), but that is either good/runs, or bad/won't run. Thats usually the thing with a pick up coil. Check timing at idle 700 rpm or so, I'd go with 12 deg BTDC. I am thinking vacuum leak. I'd also suggest, after the things I posted are checked, (I use WD-40, not sure if you have that) starting fluid in spray can around (with it running) suspect vacuum leak areas, i.e. carb base, vacuum hoses ect.

 

Have now checked the service codes, they are 36 and 43 wich seems to indicate that the spark timing module has unstable voltage, so I need to locate the timing module and check the wiring around it.

Anyone who can say where it is located in the car ?

Camaro Bo, Sweden

 

I'd suggest replace the entire ESC distributor, electronic spark control. That is probably the pickup coil insulation breaking down (I'd be real surprised if the one you have is original) You can replace the pickup coil, but it is a REAL pain.

 

Ok, it will be some winter work in the garage, it is just a couple of weeks before it is time to put the car to winter sleep.

And take out the winter car, a BMW Touring -94, that are imported from Italy two years ago. No rust and by me turned into a race look, British racing green metallic and twin gold stripes, why grow up and be booring

Thanks for all the help !

Best Regards from Bo in Nybro, Sweden