OK, I have installed a 93 3.4l SFI-DIS in my truck. Now, when driving sometimes the check engine light comes on. No Biggie, go to pull the code. However, when I jump terminals A-B, and turn key to run mood, the check engine light stays on. It should blink the codes correct?? Just like any other ODB1 like the original 93 truck engine, and my 91 camaro. If so, any suggestions on what I wired up wrong??

I am quite sure what the code is, but I prefure to know exactly what the code is, and for any future problems I will have.

 

A is a diagnostic enable , & B is a ground . Try grounding A out directly & see if that works. If not recheck the wiring from aldl to ecm.

 

Finally got around to being able to work on this.

B ohm checks out to ground.
A goes back to ecm.

I jump it, turn key on, check engine light stays on.

I also created my own light system to see if it was my dash wiring at the light. The home setup stays on just like the dash wiring.

Any ideas from here??

 

You need to check with other 93 V6 owners. Not all OBD-I ECM's can be flashed to show the DTC's on the SES light. In the V8 models, 93 could enter diagnostic mode with the paper clip, but 94 and 95 will not. I don't know enough about the V6's to tell when they changed over, or if they changed over, but that might explain why it doesn't flash.

 

I heard the 94/95's couldn't. Thats one of the reasons I went with 93. However, my haynes and chilton say 93 and 94 could. Plus slowzone (autozone) tryed it with the little jumper trick too. Would think they would know if they needed scanner or jumper. But their idiots anyway.

 

Have seen bad ECM's do this too....

 

Crap, didn't want to really here that. I do have a second one. Says its from an automatic, but if you search for an ecm, it "says" auto and manual are same part number. I guess I will try swaping them.

 

Changed, ecm, still does same thing. So I doubt its the ecm. Any ideas on what I might have gotten crossed in the wiring??

 

You should try grounding the diagnostic enable wire at ECM & see if that works.
Make sure you got good connections at the terminals into ecm.
Also check the grounds for ecm. There are 2 wires that go to diag. connector/ aldl from ECM, they're not crossed?

 

Ecm grounds in same place, right to the front of the engine, thru the harness.

Engine does have ground to battery, and the ground strap to firewall.

Correct, 2 wires to that plug under dash. Data link, and ecm check.

So your saying, try grounding that one strait to the body?? Attempt to check it that way?