Hi

[Buckey]

I posted this on another site.First I would like to say hi.I recently got an 89 MJ with the 4L auto.The problem is it sits and idles great but as soon as you give it gas it pops and has no power.Anyone have any ideas what this might be..

 

Buckey

[87manche]

check the fuel pressure, a pump not putting out enough volume or a clogged filter would give those symptoms.

If it meets the spec for pressure ad volume at the rail then Iwould look at TPS, or the MAP sensor next.

in fact, I'd check the TPS first, just because its easier than dealing with the fuel rail.

[carnuck]

Raunchy gas? Someone mess with the dist? REALLY bad vacuum leak? Spark cracks in the dist cap? Mixed up plug wires? 1-5-3-6-2-4 is the firing order

 

 

Worst case scenario is blown head gasket.

[BLHTAZ]

Hey...welcome to the site... :cheers:

 

Raunchy gas? Someone mess with the dist? REALLY bad vacuum leak? Spark cracks in the dist cap? Mixed up plug wires? 1-5-3-6-2-4 is the firing order

 

 

Worst case scenario is blown head gasket.

 

I believe it would be one of these if not a combination of more than one.

[fiscus]

I'm gonna say bad fuel pump also or possibly clogged cat.

[DirtyComanche]

I vote TPS. It is adjustable and should be checked as it's a lot cheaper than replacing anything...

[mjeff87]

I'd check the cap/rotor condition, as mentioned, also.

[speed_racer]

I'd say TPS.

 

Try disconnecting it, starting the jeep, and reconnecting it.

 

Fiddle with it, by disconnecting, and reconnecting, starting the jeep each time.

 

My buddies 4.0 does hte same thing, a quick unplug n replug of the TPS, fixes it, obviously means it's bad, but helps you narrow it down.

 

Good luck!!

 

If it's idling right... personally... if it was in the fuel... I'd say filter.

 

And I wouldnt necessarily jump to the Distributor n' all that, b/c they SHOULD affect IDLE as well if configured incorrectly.

[carnuck]

I spray my TPS with contact cleaner/anti-corrosive once a year. Usually right after I power wash the engine to get it to run right again!

[fiatslug87]

Check the EGR valve and transducer. Although "popping" doesn't really make sense for the EGR, it's an easy check.

[Buckey]

Thanks everyone I will try it all.I will be replacing the engine soonanyway but someone is interested in the 4.0 so I was just gonna try to see if I could get it to run properly is all.

 

But I do appreciate it though

 

Buckey.