Won't idle

[money_pit_yj]

I'm getting the jeep ready for Disney. I just three linked it and put full hydraulic steering. Had to cut the pipe 2" below the header for it all to fit so one side is running all the way out the back and one is straight out of the motor. Stock gm pump, Vortec 454. It will not idle. I can crank it and keep foot on gas and hold it to about 1000 rpm and it does fine, drives fine and will rev high but it will not idle. Any ideas? It is going to muffler shop tomorrow to get pipes fixed.

 

[gottagofast]

Idle air control.... Tps.... Vacuum leak

 

[muddinmetal]

Seems like an air leak, but I wouldn't start diagnosis until I had the exhaust run.

 

[gottagofast]

Agreed...

 

[Fire Freak]

Is it a throttle body motor? If so have you missed with the wiring harness that plugs in to the top of the injectors? In the old throttle body motors if they get swapped it will crank but not iddle

 

[CHASMAN9]

You said you cut the pipe 2" below the header, maybe 02 sensor?

 

[money_pit_yj]

You said you cut the pipe 2" below the header, maybe 02 sensor?

O2 sensor is there. I am on my way to muffler shop. The only thing that has changed since it ran last was the pipe being cut so I'm pretty sure there is some kind of correlation.

 

[Neal3000]

Idle air control

This

 

[bigs10blazer]

or throttle position sensor

 

[money_pit_yj]

Cranked up and idled fine this morning, not one issue.

 

[gottagofast]

Exhaust cut short near O2 sensor will totally throw off mixture ...

Glad u got it working.

 

[44BRAND]

Exhaust cut short near O2 sensor will totally throw off mixture ...

Glad u got it working.

^^^ This. If O2 is too close to the end of the pipe it will read full lean, like a vacuum leak. Recheck after exhaust is fixed before anything else, most likely will be fixed.