Let me start off by saying these forumss have been a wonderful help with my truck (not so much with the wife but I need a working vehicle to make money and keep her happy, so a few hours a day researching is required)

Been working on my 93 3.9 the past week trying to resolve my Check engine code 27 which is accompanied with rough idle, a strong smell of fuel and poor acceleration.

So Far:

All injectors are around 15.9 OHMs, and I have tested continuity from the PCM connector to the ground of each injector.

Just replace the oil shaft/ Distributor drive gear and bushing and indexed the distributor which has given me a slight improvement in overall running.

I have unplugged the injectors one at a time while the engine was running and the only cylinder that had a noticeable difference in idle was #3 and if I remember correctly the same results when I pulled the spark plug wires.

I have not cleaned the IAC yet and wasn't sure if that would cause the 27 code.

I'm just wondering if I might be looking at needing a PCM or what else I need to look at.

 

Typically a code 27 will be the injector, but it also could be the wiring or plug to the injector. It is a typical problem that the power splices fail, that could be the cause. Test the power of the suspected injector (or all injectors) and the power/+ of each injector is spliced together. Then test the continuity of the negative side to the PCM.

 

Thanks for the response

Continuity of the negative side to the PCM is good.
I haven't check the power side yet. Any special way I need to do that?
Is the splice your talking about the one under the relay box?

Funny thing is today I had a 5-10 minute spurt after starting the truck where the Check engine light was off and it ran beautiful then just came back on and was rough again, which made me think the splice needs to be checked. The other thing I noticed after it went back to CE mode the tranny was shifting funny it didn't want to shift up unless I hit neutral then back into drive the it upshifted

The previous owner mentioned something about the pcm being replaced recently but not sure when and the one in there looks looks like a used unit. There is no tag on it and I'm not sure if its even the right one so...
As a precaution I stopped by the dealer to get my PCM number via the vin and all he would give me was the part number and not an OEM number. Is there a way to cross reference it? Ive just begun to google it but so far not much luck.
Part Number is R6027774
I've come across 3 possible OEM numbers which crosses to 2 different reman. units I need to check a few things before I jump to the PCM but looking to get this info

 

One thing I just ran into on my 93 is the #5 injector plug connections were loose, so one day it would ruin great, then it would run like crap, throwing the cel and it came up injector driver failure. But I ended up pulling the wires out of the back of the clip, slightly closing the connectors and slapping it back together. And voila' no more miss, no more cel, and I dunno if its just me but it seems to run much better and feels like the ol' girl has more get up now. But give it a try.as I've learned its usually the free to check stuff thats wrong.
Chris

 

well after checking the wires I grabbed a PCM (figured it wasn't to pricy if I was wrong). Put it in this morning when I got to work and ran the truck for 10-15 minutes.
So far no CEL, still a little rough but I figured the PCM needs to calibrate which it will star to get its chance if I have any service calls today or at lunch which ever come first.

Thanks for the help all and I will keep you posted