Mechanics

CHEVY

1989 Chevrolet Truck

Electrical problem
1989 Chevy Truck V8 Two Wheel Drive Manual

Just bought an 89 Chevrolet 3500 p/u with a 7.4l and I am trying to get it running right. I have a fast idle which seems to have improved after I changed the plug wires, cap, & rotor. I also have a miss/loss of power when I try to accelerate quickly. I noticed the inside of the distributor, under the cap has some rust on the top where the rotor slides on. It also has a lot of corrosion on the bottom area below the rotor. Could this be a cause or contribute to my problem? If I have to get a new distributor I was thinking about upgrading to maybe a MSD or some kind of electronic distributor. I would like a little better performance but my main concern would be gas mileage. Any suggestions? I have fuel injection and seem to get a good spray from the injectors, I have cleaned the throttle body with some spray cleaner and have also added some fuel additive.

Another issue that no one can seem to help with is on the passenger side of the motor there is a sensor in the head between plugs 4 and 6 that has the end broken off of it and the only wire out of the three that are not hooked to anything and that is long enough is a green wire which also has the end broken off of it. The dealer says their computer does not show anything in that location. Can anyone tell me why I need 3 sensors? There are two other temperature sensors one in the drivers side head between 3 and 5 and one in the intake just behind the A/C Compressor.

Thanks
Avatar
Nov395
July 16, 2010.




I wonder if your electric cooling fan works- I bet not. that is what it is for. One sensor operates the gauge, one to the computer, and the one that is broke goes to the cooling fan. the schematic i'm sending will show you. at least for the cooling fan. check the tbi unit ofr a vacuum leak, spray choke cleaner around the base. this was a common problem and would need a new base gasket to cure it.


http://www.2carpros.com/forum/automotive_pictures/406719_cooling_fan_circuit_1.jpg


Hmac300
Jul 17, 2010.


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