Hi, I acquired a '89 2wd V6 short bed, and it has some problems.

I replaced plugs, wires, distributor cap, rotor button, fuel filter; however, it still runs rough at all speeds.

The fault codes I get are: 12 34 14 24 35 32 15

Any Ideas will be appreciated.

Thanks,
Craig

 

The codes mean:
12 -normal (battery disconnected within last 50 key-on cycles)
34 - Speed control Solenoid circuits
14 - Manifold Absolute pressure (MAP) sensor voltage too low
24 - Throttle Position sensor (TPS)out of range
35 - Rad Fan control relay circuit
32 - EGR system failure
15 - No vehicle speed sensor signal

The MAP sensor and TPS could be having an effect on the way the engine is running.
An EGR fault could effect that as well, my understanding is that a fault in this system effects the engine mostly at idle/low speeds.
MAP and TPS subjects have been brought up numerous times. Do a search, and if ya got any questions, feel free to ask.

 

Thanks for the reply dodgerules86.

I've done some further reading and testing:

I cleaned every electrical connection I thought was relevant.

The egr valve (code 32) didn't move when I stuck on a vacuum pump, so I replaced it ($44.95)-- no noticeable improvement

Fuel pressure is 18lbs. It's supposed to be 14.5. I wondered at, but didn't replace the fuel pressure regulator.

I read somewhere (maybe this forum) about several people having trouble with the ignition pickup, so I tested and replaced that ($28.88) -- Big improvement, but still not perfect.

Now I only get the 34 code, in addition to the normal 12 and 55 codes. I can't find a diagram where the speed control vacuum or vent control solenoid circuits would be (I have the Haynes manual, I guess I need the factory service manual, or a friend that has it!)

Thanks,
Craig

 

I know there is someone on this forum with a service manual from around that time.
I have one for either 1990 or 1991.. but I'm half a world away. Sorry.

 

How are you checking th codes? Is a special computer required?

Justin

 

No computer or special equipment required!

You turn the switch on and off rapidly three times, and then turn the switch to the on position. The check engine light then flashes the codes. Read up on it in your Haynes manual, etc.

Good luck,
Craig

 

Iuploaded photos of the speed control section of the 89 service manual (9 pages); you can download them here:
http://rapidshare.com/files/36805820...rol89.zip.html

Regards,
Greg

 

Good deal, I'm grabbing them now.

Thanks,
Craig