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Catalytic Converter Issues

O

Olympia

NAXJA Forum User
Location
Olympia
Hi all,

some of you remember my cheap jeep i bought for 100. This weekend I cleaned out all of the intereior and went to the junk yard and pulled out both driver side window glass, and a few parts for the front end. so as far as body wise goes its doing good.

Now I have a rought idle and i put gas treatment in and ran it, and cleaned out my carb and that helped out immensly, but when I am in drive and come to a stop, the engine will start to lug and low idle and then die. My father in law told me it was a plugged catalytic converter? Would this cause bad back pressure and cause my engine to run rough?

I have an 85 cherokee 2.8 V6 4X4. Thanks to anyone who has answers.
 
It could be a number of things..fuel filter, fuel pump, fuel injector(s), possibly the cat but you would smell a rotten egg smell normally, maybe even a vacum leak.
 
I thought it would have somethin to do with my fuel system, so I added the gas additive thats suspose to take out water and junk. Were would my fuel pump be, and were would my fuel filter be?
 
Okay, I'll check the filter probably just replace it since its cheap anyways, i'll put the addative stuff in again. Should I do a physical look at my fuel lines to make sure there okay? Other than going to the fuel pump anything else that I can look at?
 
Fuel lines are generally not too problematic, usually you would be able to smell fuel...even a small leak. I would also take some Sea-Foam and run it through the brake booster -instructions are on the can..don't use the whole can!! But this will clear all the gum out of your motor. After you suck the sea foam into the booster (slowly with engine hot) shut it off let it sit 5 minutes then drive it around...it's gonna smoke like a chimney for a while so try to avoid the police. this stuff is amazing Many mechanics recommend it. You can put it in your gas tank, in your oil (crankcase) and in your upper cylinders (through the brake booster) However if you add it to your oil change it before reaching 100 miles. Your brake booster is on the firewall on the driver side. gently pull the hose off the valve and just barely tip the can to the hose and it will suck it right out of the can...if you pour too much at once you'll stall it.
 
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hmm... never heard of that stuff. Anyways had a chance to drive it yesterday, and anytime I was in drive and started coming to a stop, I would have to shift to neutral and feather the gas to keep the idle up, other wise it would get to low and die. In park and reverse it idles fine, I think I will also do a compression test, timing check, and check out my spark plugs.
 
So if you have it in park, or in reverse at idle its fine? but in Drive or neutral it dies?...Maybe you should change the name of this thread to a different topic because I seriously doubt it's the cat. and you may get alot more responses with a topic like...Fuel Issues??...or Motor Dies..
 
Olympia said:
hmm... never heard of that stuff. Anyways had a chance to drive it yesterday, and anytime I was in drive and started coming to a stop, I would have to shift to neutral and feather the gas to keep the idle up, other wise it would get to low and die. In park and reverse it idles fine, I think I will also do a compression test, timing check, and check out my spark plugs.
Click to expand...
Thats a good Idea, Also get a new rotor button and cap.
 
If you're going to use Sea Foam on it you don't have to use the brake booster lines. Just pour it in the carb with the air filter off. The brake booster way are for those with fuel injection.
I have used it on my 85 and it really cleans out a lot of gunk.
 
yep its carbed, and i wanted to take off my cap anyways and check for water. And I'm definately going to look into that sea foam stuff.

just to reiterate that its an automatic, and when I first start it it idles real rough, after its warmed up its a little better, when I am in drive and i start to come to a stop the idle will drop and i'll have to shift it to neutral and press on the gas a little to keep the engine from dying, and now that I think about it I have to do the same thing when i am in park. I have only reversed in it a little and seemed fine, so I guess at any time the low idle starts it wants to die. Definatley going to take a good hard look at my carb and that whole assemebly.
 
jeepman121 said:
It could be a number of things..fuel filter, fuel pump, fuel injector(s), possibly the cat but you would smell a rotten egg smell normally, maybe even a vacum leak.
Click to expand...

Not to mention a plugged cat often starts to glow it gets so hot.
 
the fuel pump, BTW, is located on the front half of the engine, not in the tank for the 2.8l and IIRC the filter is located behind the fuel inlet where the line screws into the carb.

I would inspect carefully for a vacuum leak before I dug too deeply into other causes. Extra air getting into the mixture can give you the problems described and usually costs almost nothing to fix.
 
It sounds like your engine is sucking air from somewhere and more than likely, it’s the throttle body. I’ve had a couple of carbureted vehicles that would run rough and stall at low RPMs, and that was the fix.
 
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