weak spark, tested term. 1 on coil and getting 12.4 v. trem,. 15, 12.4v. ordered power stage. where is ballist resistor and radio suppresion relay and how do you test each one. also does the 89 740 turbo have a speed sensor behind head and what does it look like?

 

Also check for Injector pulse.

To check if you have a speed sensor look at the back of the engine where the trans meets the engine.If you have one it will be at the top of the Bellhousing. Also check the Dist. If it has a plug with wires going to it you won't have a speed sesnor.The sensor is in the Dist.

The Radio suppresion relay should be mounted to the coolant bottle. It could also be mounted on the left side under the hood by the inner fender. It is a black relay with a plug and 4 wires.

 

where is the ballist resistor and how to test ?

 

Im not sure if it has a ballast like on the old cars. I think it might be built in.

I have never messed with one at all. Should tell you how much they would go bad.