Exhaust Manifold leak = Jeep can't idle w/out foot on gas?

Long story short... on our way back from Utah, I overheated the Jeep. It's a 96, auto. Had to have it towed to the nearest town because once it cooled down it didn't want to crank back over.

Got to the towing place, the Jeep started up. Went in to pay... came out, Jeep wouldn't start.

Mechanic there put in a new starter... still had issues. Had to trailer it home. He also said I didn't have enough compression, most likely a head or head gasket... omgoose nooooo!!!

Talk to my brother in-law in Canada who is a mechanic, doesn't think it's a head gasket/head but possible burned a valve or valve gasket.

Father in-law comes over today and works on the Jeep with my wife...he finds that the distributor cap/rotor is totally crapped out and thinks that's why it wasn't turning over. He also noticed a welded spot on the exhaust manifold that is now leaking... and sputting out smoke all the while. Hence the reason I gotta put my foot on the gas to crank it over (not enough compression w/that leak) and it wont idle w/out the foot on the gas.

Does this sound about right? exhaust manifold leak = wont idle...It also makes a sucking/blowing air noise pretty bad to (guessing that's the hole) the welded spot melted when the Jeep got too hot apparently.

My father in-law also checked the valves and said they're A-ok.



The busted weld where it's leaking is the shiny spot there...

Also, for a replacement exhaust manifold... how are the chineasy ebay ones? I haven't heard too much bad about them...

http://cgi.ebay.com/ebaymotors/1996...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Wow... that's a ridiculously long link, sorry.

And more than likely i'd be inspecting the engine mounts too... to insure that there wont be any future cracks. The Jeep has Hooker Long Tube Headers in right now...

Thanks!

P.S. I hope you're all jealous of my wife... while I was at work she worked on my Jeep...put in a new distributor cap/rotor, new oil filter, and air filter... she was going to do the lower rad hose but didn't know how =)

Anyone...?

Spend a little more money and get the APN header. Its a pretty good little unit and it has a lifetime warranty. Theyre customer service is great too, if you ever have to deal with them . Personally I dont know anything about the ebay header to answer your real question.

There's no doubt you need a new exhaust manifold, so I'd say go ahead and replace it. I haven't heard much bad about the ebay manifolds either. It seems as though this could be a likely cause for the idling problem, especially because it didn't do this before you had to pull over for overheating.

Eh, I don't think this is your problem with the Jeep not being able to idle. I just took my cracked exhaust header off. It was cracked in 3 different places, and I've not had one problem with it idling or anything in the 4 years it has been cracked (Never could see the crack until I dissasembled a few things, which is why I never changed it)

Also, compression happens inside the cylinders, not in the exhaust. With the exhaust you wouldn't have as much backpressure, not compression.

The times I've had to deal with keeping my foot on the gas to idle it was after the battery has died. (I was told this by my mechanic when we brought my friends TJ to him when we couldn't restart it) When I go to jump it, the computer basically forgets all its information, so it can't remember its idle settings. Thus, it takes a little for it to remember, while you teach it how to idle

Well, the 'mechanic' in Burley said it's a compression issue...but who knows. The towing company there has two hispanics that live on the property in a trailer... and get paid $60 an hour.

Anyone else heard of not being able to idle after overheating/cracked manifold?

Trying to determine if there might be anything else wrong with it... other than needing a new lower radiator hose and exhaust manifold. The dist. cap and rotor had to be replaced too... apparently they were really charcoaled up and burnt.

My idle issues have been tied to either the map sensor, o2 sensor, or battery. At different times and in different manners, replacing each of those fixed a problem that had to do with running and idling.

wont idle without foot on gas could be dirty iac or weak battery. iac is on throttle body and weak battery output(could be bad connections) can cause idle problems on electronically controlled engines.

Do some troubleshooting. Buy a $10 compression gauge at HF and test the compression yourself. A headgasket is not likely to cause a low idle. Check your coolant for contamination from a blown headgasket.

An intake leak will cause a high idle. A plugged Cat can cause a low idle and engine overheating as well.

A dirty/stuck/bad IAC can cause a low idle problem. A MAP can cause an idle program as well.

TPS is not normally a cause of a low idle.

Is there a difference in idle between hot and cold?

Check your battery voltage when running. It should be around 13.8v or so. If it is lower than 12, you have a charging problem.

Veryify your grounds, especially the one from the rear of the head to the firewall.

Good Luck.

Well, the new rotor is in, thanks to my wife. It sits at idle now.

Now I just gotta get an exhaust manifold and get that in and I should be good to go.

Yahoo! It was definately good hearing that thing turn over finally!

Although the sputtering air sound from the leak in the exhaust doesn't sound nearly as cool with the flowmaster.

Is there still a vac leak? Check ALL vac lines? Mine last week was a vac line into the TB from the MAP sensor. It idle'd like crapola til I plugged it back in.

My 99 sport wouldn't idle for 3 days once. I checked everything that I and everyone I knew could think of, but nothing worked. I happened to notice that one of the battery terminals was a little (really not much at all) dirty. I decided to clean them for shits and giggles, then decided to start it and see if it would idle. I started it up and it idled once again! It might be something so small that is usually over looked. Just my xp. GL.

I haven't checked any of the Vac lines yet... it's idling fine now that it's got a new dist. cap and rotor in.

The only issue i've got now, is replacing the exhaust manifold.

Now the question is, go with an APN header or the chineasy ones on Ebay... haven't heard much bad about the chineasy and it'd definately be a lot kinder on the wallet.

Glad to hear you're making progress. Get it fixed and let's go wheel it!

As long as you don't take me somewhere where I don't break it and have to fix it! =)

Hoping to get the new manifold sometime in the next few days, at least get it ordered. It runs... but sounds really bad with the leak so I don't really want to be driving it right now.

Bdiddy11 said:

As long as you don't take me somewhere where I don't break it and have to fix it! =)

Hoping to get the new manifold sometime in the next few days, at least get it ordered. It runs... but sounds really bad with the leak so I don't really want to be driving it right now.

Click to expand...

also check your motor mounts.