Jaccob

I have a 1990 Silverado
4.3 V6
4X4
Manual Trans.

Problem is this;

Truck is running rich, and shakes as if it is missing. I changed out the distributor cap, rotor, spark plugs, and wires. No fix. I checked the timing, and for some reason it was at 10 degrees. Factory setting is at 0 degrees. so thats what I went for, but unfortunately 0 degrees is not a happy place for my truck(it dies) So i have it at 4. But still same problem, shaky at idle, and chugs while driving, smells really rich, and has mileage sucks.

One more thing, while in reverse mostly, when I press in the clutch to stop and go into 1st after reversing, truck bogs down so low it dies or almost dies. this only happens every now and then. Sometimes happens going forward as well....

Let me know if you have any ideas
Thanks!
Jaccob

Richardx2

Did you bypass the ECM when you set the timing? If you don't then the timing will be off because the ECM will readjust the timing.

Jaccob

Thanks for the reply Richard.

Yes, I did unplug the ECM wire. I was told maybe the coolant temp sensor or fuel regulator? What are you opinions on that?

Thanks again!

Richardx2

I would lean towards the temp sensor. It sounds like the ECM is thinking that the engine is cold and running a rich air/fuel mixture to compensate for the cool engine.

Jaccob

The weird thing is though, my temperature gauge seems correct. Maybe just not sending the signal to the ECM, but is being relayed to the instrument panel?

Im going to replace this saturday and I will post what i find out.

Also, my timing is set at 4, not 0... Is this a bad thing? I would really like to get it to 0 (factory) but it bogs out when i do.

Camaro 69

The engine has a temperature sensor for the ECM, and a separate temperature sending unit for the gauge.

Jaccob

Thanks Camaro!

I appreciate the help greatly.

Jaccob

replaced the fuel filter and the coolant temp. sensor,

Truck is running much better and has more power. Now only thing left to do is change the timing to 0 and hopefully it doesnt die.

Thanks for the help guys!