Comanche Idle Issues

[mrast2u]

Comanche was bought knowing it had not ran in years, but felt like tackling this project.  Always wanted a Comanche of my own.  I will list everything I have done to the truck... in hopes someone can see something I might have missed.  I am open to suggestion everyone :)

 

1989 Jeep Comanche  4 L  4WD  Automatic

- ECU replaced

-TBS replaced

-Idle speed control replaced

-Oxygen Knox sensor replaced

-temperature control sensor replaced

-ignition replaced

-starter relay replaced

-fuel injector replaced

-fuel rail rebuilt

-fuel pump/filer replaced

-spark plugs replaced

-vacuum leaks sealed

-electrical connections checked

-neutral safety switch replaced

 

Here is what the truck is currently doing.  As a side note, it took me 2 years to get to this point... to actually get the truck to start.  

The idle is off.  Either it is running way too high, or other times it is low and stalling out.  Does not want to accelerate.  Acts like maybe the fuel/air mix is not right?  Possible timing advance not right (checked the sensors).  I have not checked the sensors from the transmission to the TCM at this point.

 

Any and all advice would be much appreciated at this point.  Thanks for reading, and looking forward to all ideas.

[boxyjeep]

I'd check really closely to make sure your IAC is working properly and wiring is sound.  Beyond that, it sounds like an issue with the TPS or the coil/cap/rotor/wires.  Check all of that stuff out.

 

I also ran into a lot of idle issues with my '88 that took a long time to figure out.  I'm in year 2 and believe it's been solved with a new cylinder head, but this is clearly one of the most problematic issues to fix.

[mrast2u]

Thanks for your reply!

 

TPS has been replaced as well as the coil/cap/rotor/wires have been checked as well as replaced as needed.  I am also in my second year.

 

Engine has been rebuilt, and the only problem with that was a stuck exhaust valve which I have repaired.  

[JMO413]

Did you adjust the TPS correctly when you installed it?

 

http://cruiser54.com/?p=54

 

I would read through his whole site. Make sure 1-5 are done. 

[JustEmptyEveryPocket]

How old is the gas in it?

 

If you have been working on it for 2 years, I hope you put in some new fuel.

 

Next step for my peace of mind would be to check fuel pressure. You want ~31, jumping to ~39 if you remove the vacuum tube at the Fuel Pressure Sensor.

 

After that, its not a bad idea to run a compression test and a leak down test on a vehicle that has been sitting that long.

 

Otherwise, follow cruiser's steps. cruiser54.com FTW.