1992 Cherokee runs like junk, ready to burn it down

[Ecomike]

It electrical not mechanical. So even when its running badly at idle it should stay steady. I had mine read the right pressure but would not hold the volume when I accelerated. Same exact symptoms black plugs popping in the intake. You may try and check the relay for the pump or the ballast resistor on the drivers fender two likely culprits

I would set a volt meter up to see if power to parts like the fuel pump are coming and going.

One thing no one has mentioned yet, is the 12 volts to heater in the O2 sensor. If it is not getting to the O2 sensor, it will work when real hot, but come and go when warm, with your exact symptoms.

 

[79ford302]

I've tested most of those things when it runs bad. I don't think it has an injector sticking, the flooding problem seems to be cured by the new tps. The O2 sensor is new. Where is the fuel pump ground located? I'll hook my meter to the fuel pump and check voltage when running. Is there a way to test the ignition coil and pickup coil?

 

[scottmcneal]

I had a coil going bad on my junk, it would run worst the hotter it got..

Have you checked the timing?

 

[ruger81]

I had a coil going bad on my junk, it would run worst the hotter it got..

Have you checked the timing?

The timing is set by the puter

 

[Ecomike]

I am not sure on the 92. There should be a quick connect, electrical near the fuel pump, that is a good start for cleaning the contacts. I fixed both my Renix 87 and 89 fuel pumps by just cleaning the QC contacts a few years ago.

O2 sensor may be new, but the wiring and relay and fuse that powers the electrical heater inside the O2 sensor, that allows it to work cold and at idle is not new!!! And the wiring can be damaged from contact with the manifolds and drive shafts. If the heater does not get power, it drops out of closed loop near idle and plays hell making a rough idle as it comes and goes between closed and open loop operation.

 

[Ecomike]

I had a coil going bad on my junk, it would run worst the hotter it got..

Have you checked the timing?

A hot air dryer is good for testing parts for heat sensitivity, like the coil and CPS.

 

[superdave]

Does it have a catalytic converter? If so, could be clogged. Would make it run decent at idle but bog and sputter the rest of the time.

 

[scottmcneal]

The timing is set by the puter

So it can't jump a tooth.Nice to know.

 

[79ford302]

Does it have a catalytic converter? If so, could be clogged. Would make it run decent at idle but bog and sputter the rest of the time.

Cats have been removed. I'll try a few more things on it when I get a chance. Thanks for the suggestions