My truck runs great when it is cold but dies when the engine warms up. I can restart it but it hunts really bad and then dies. I didn't have time to mess with it so I dropped it off at the local shop. They pulled codes and it reported a problem with the idle air bypass, so they replaced the solenoid, but it didn't fix the problem. They messed around with it and told me that they only had a code reader and not a scanner for my truck and that they could not fix it. They suggested taking it to the dealer.

I have looked at several code scanners online, any suggestions on the best one for pulling realtime info on the EEC-IV system?

Thanks,

 

Sounds like your TFI module. Gray box on the side of the dizzy.
It went on my 86 302 FI and the engine would just die when it warmed up and then crank up five minutes later only to die again.

 

I got a code scanner and I am getting codes, 18, 12, and 44. I replaced the tfi and the code 18 went away but the truck is still doing the same thing. Any Ideas? I am going to replace the idle air bypass for the hell of it also due to the code 12.

 

Was the ECM reset after the IAB was installed?

 

yes the codes were reset. I have not put the iab on yet, that is the next thing I will do, I have just replaced the tfi.

 

No, not having the codes reset, having the ECM reset. There is a difference. Anytime you replace a an actuator, like the IAB, you must reset the ECM so that it can relearn the new device's parameters. Otherwise, it is presuming that nothing has changed, and your new part will function just like the old one. To reset the ECM, disconnect the negative battery cable, and then turn on the headlight switch for a few minutes (this will drain the capacitors). Turn off the headlight switch, and reconnect the battery cable.

 

I assume it was reset, I had the battery unhooked over night, it should have killed it. To reset my jeep you only have to unhook it for 5 minutes.

 

I replaced the IAC valve and nothing changed. I have also tried unhooking the EGR valve when it is running rough and that causes no change. The fuel pressure is also okay. ANy other ideas?

 

Okay after 1.5 F'en years the thing is fixed. The magnetic pickup in the distributor was bad. The resistance on the thing was proper, but it was bad. It was a heat issue and when it got hot it was trashing the timing input. Again, even with it hot, the resistance checked out. Replaced the thing only because everything else had been replaced and it fixed the problem.