Anyone install a 4.3 with painless wiring?

I tried to get the factory 4.3 harness in my CJ5 wired up as correct as I thought but the engine is doing a bunch of funky things.
Not a lot of hours so far but some of the things its doing are:
occasionally it won't idle when cold.
occasionally it idles high when cold (tonight it idled really high for 5 min!)
it throws a code sometimes for the VCC that I don't use.
Anyways, I'm wondering if its because I might have messed something up with the wiring.
Anyone install the painless TBI kit on a 4.3?
Will it eliminate the VCC and such?

 

I will be watching this thread closely because I too have a 4.3 that is getting ready to go into my '59 and will need to fab or (damnit) have to buy a wiring harness.

 

VCC... or VSS or TCC?

 

It sounds like the IAC valve is not functioning properly this is if you dont know located on the passengers side of the TBI its round with a four wire plug that goes into it.
The VSS sensor I think should not affect anything at idle but with it not hooked up it may affect driving.
You need to I if I remember correctly somehow trick the computer into thinking it is in park all the time so it is not looking for the vss sensor this maybe as simple as not hooking it up not sure.

 

uh, yeah. VSS.

Can I test the IAC somehow?

 

Well, I replaced the IAC sensor today and it idled super high for a long time. When it got all warmed up the idle dropped down to just plain high and then decided to go back up to super high. Don't have a tach connected but if I were to guess I'd say around 2000 rpm.
Is there anything else controlling the idle speed or do I have a faulty IAC?

 

You sure you dont have a vacume leak somewhere???
Do you still have the old IAC???
If so put a pair of pliers on the pintle and unscrew it a bit probally 1/8 - 3/16or so then put that in do not hook it up that will disable the IAC and give it a try if all seems well the IAC is bad if it still idles high check your fuel pressure it could be fluctuating.
OH if it does not start you may have to crack the throttle a little bit .
you may also have a bad throttle posistion sensor you can check them with a ohm meter.

 

The throttle body base gaskets are known to leak when they get old. Might be a good place to start.

Things I would check:
Vacuum (as in leak)
Timing
Is the coolant temp sensor hooked up/working correctly?

You might want to invest in a factory service manual for whatever the engine came out of. It could make your job troubleshooting a lot easier.

Good luck!

 

Ok, new TB gasket
new TPS
new IAC (even tried the fix)
still idles real high.
Should I also point out that I put in a new battery because that old one wouldn't hold a charge.
A friend was looking at it also and he thinks because the battery was so dead that it wiped the computer's memory and it needs to relearn. Does that make sense?

 

Depends on what year you have but that could be the case, although idling that high is usually not a sign of a relearn procedure. I spoke to a GM engineer when I was gathering parts for a similar conversion who told me not running a VSS could create confusion within the PCM and cause idling issues as you describe (doesn't know where to set the IAC). Essentially he told me that if it doesn't have a Vehicle speed reference the computer doesn't know where to set idle and can cause the idle to progressive change (he thought it would climb to a point then level off) each time the engine was started. He also mentioned issues with the egr system could come up. Not sure if that's what you have going on here but a definite possibility. As mentioned, check all the simple stuff first as as the PCM could be trying to compensate for a mechanical issue (vacuum leak etc.). Check the intake around the runner ports for vacuum leaks also as that is also common. Nickmil