O/T Jeep Daily Driver Backfiring

I have a 96 jeep cherokee 4.0HO a/t 2wd, no codes stored. When I start it up, I can drive for about an 1/8mile then it starts backfiring and popping for a minute or two, then it clears up and drives fine until I shut it off again.It has new plugs,wires,cap, rotor.I'd Appreciate any help.

 

You may have dirt settling around in the fuel filter. Swap it out and see whats next. Should have a Schrader valve on the fuel rail to check fuel pressure, I'd look for 55-65 psi.

 

I would love to know what's causing this. I have the same problem with my '98 Cherokee and the Jeep dealer can't find the problem because there are no codes. I also checked the Jeep forum with no luck. If I find out anything I'll post it. Please do the same.

 

Had a similar problem with my '93 Grand Cherokee last year. Was the Oxygen sensor. Hope that helps...

Ben

 

Wouldn't the oxygen sensor throw a code?

 

Check the ignition trigger which I believe was by the flywheel on some years.

My son had a Jeep pickup that had that problem.

No shop could fix it.

Every single one said it needed lots of work to track it down, but nothing they did ever helped.

As a very last resort, he asked his dad. He always tells me last.

I noticed that every time he pushed in the clutch, the bellhousing moved a little bit.

He said, yeah, one of the shops said to get the worn clutch parts and trans mount replaced. That's why things were moving. (Hydraulic clutch?)

I fixed it for him in 5 minutes.

I got out my rat manure, excuse me, I meant ratchet, and a couple bolts.
I tightened the loose bellhousing, and replaced a couple housing bolts that didn't tighten right, and the ignition problems stopped.

I found out that the ignition was triggered from a flywheel sensor, and if anything moved around a bit, it would no longer be in alignment close enough to get good signals from the flywheel.

Make sure the bellhousing bolts are tight, and that the sensor isn't moving around a bit. It doesn't take much movement to mess things up.

 

Helped a buddy do the same thing! Must be something about the setup that causes the cases to flex and shift apart.

 

I should add that another problem with them (at least the model my son had) is that the radiator reservoir bottle is right over the electrical box with all the relays etc.

We were always having to clean the terminals of the relays, and other connections that were right under the overflow bottle.