Hey all, new to the forum. I have a 1991 Pickup, 3.0. It died on me while driving home a few weeks back. Bear with me, because I am far from a mechanic.

Got it towed home and learned how to pull the code. I am getting a code 12, RPM signal, igniter, distributor, coil.... I blindly replaced the distributor, no luck. I tested the coil, replaced the igniter, still nothing.

I am looking at the ECU and/or grounds. The coil harness isn't getting a ground but the positive tests out with voltage. I pulled the ECU and tested the 3 ground pins and they are all showing OL. Does this mean that the ground is bad or broken somewhere, or am I just testing it wrong?

 

Had a similar issue as yourself. Driving home one morning truck just dies (94), I was going about 45mph at the time. I was getting a code 14 though. Turned out to be the ignition coil. What are your specs on the coil

 

tested the 3 ground pins against what? each other, case of the ecu, or ?

 

Against a chassis ground per step 3 in this troubleshooter.

 

Primary was about .44 ohms. Secondary was about 11.5k ohms. It's a reasonably affordable part, so maybe I just swap it?

 

the diagram says that the engine is idling? for the early tests, is your engine running?

although that ground issue seems questionable.

 

No, It wont start so I cant test that, unfortunately. Not sure if cranking it would count.

 

is that within the toyota test spec range?

did you start the troubleshooting at the 1st step in the manual? had to ask since you didn't mention it... should involve checking for spark at the plug, then working backwards.

 

Yeah, I did check for spark at the plug and worked my way back. I don't even have spark or voltage going from the coil to the distributor when cranking. Then the coil resistance specs are ok per the book. I tried swapping the ignitor, but no change.