89 yj with 4.2 litre . After driving for a while (20-30 mins.) it has a lack of power (with foot to floor it won't go over 1500rpm) gear down to 4th still the same pull over and let it sit cause it is hard to start, then when it finally starts it runs fine like nothing ever happened?????? any ideas?
yj with no power
- Thread starter flyboy
- Start date
Bounty__Hunter
Super Moderator
Your catalytic converter is clogged. Replace it with a hi-flow Catco from www.jcw.com for about $60.
Liftgate glass install help!
I second Bounty as I have just gone thru a "clogged cat" ordeal. Here's what happens: there's a honeycomb type filter in your cat-verter. When it gets old/clogged/bad it will not let your engine breathe like it should, thus decreasing your power. Eventually, if you put enough power to it, it could break apart and pieces of that honeycomb could get lodged in your muffler. You might hear a rattling in your muffler and/or pipe. When the parts break loose, your engine will breathe, but they could cause blockage somewhere else. If you have rattling, I would suggest replacing your muffler too, as it will be near impossible to get all the loose pieces out of it. Unless you like that rattle-can sound...? I've heard weirder.
Get a new cat.
hi-C
I second Bounty as I have just gone thru a "clogged cat" ordeal. Here's what happens: there's a honeycomb type filter in your cat-verter. When it gets old/clogged/bad it will not let your engine breathe like it should, thus decreasing your power. Eventually, if you put enough power to it, it could break apart and pieces of that honeycomb could get lodged in your muffler. You might hear a rattling in your muffler and/or pipe. When the parts break loose, your engine will breathe, but they could cause blockage somewhere else. If you have rattling, I would suggest replacing your muffler too, as it will be near impossible to get all the loose pieces out of it. Unless you like that rattle-can sound...? I've heard weirder.
Get a new cat.
hi-C
Bounty__Hunter
Super Moderator
I had it happen to my '88 YJ 4.2L, the power loss was gradual as you drove the jeep, getting worse the longer of drive you had and eventually it wouldn't run at all.
flyboy, your air filter is black... black with oily residue? or just regular black?
if it's oily residue then i would check the tubes connecting to the PCV valve and the other tube connected on the valve cover towards the fire wall
if your engine is like mine and constantly kicks oil into your carb/air filter, then you might want to install seperate smaller air filter for the second tube. i know the PCV has to attach to the air filter housing, so there's no much you can do with the oil coming from that.
Also remember to block the small hole on the side/bottom of the air filter aousing where the oily tube came from
if it's oily residue then i would check the tubes connecting to the PCV valve and the other tube connected on the valve cover towards the fire wall
if your engine is like mine and constantly kicks oil into your carb/air filter, then you might want to install seperate smaller air filter for the second tube. i know the PCV has to attach to the air filter housing, so there's no much you can do with the oil coming from that.
Also remember to block the small hole on the side/bottom of the air filter aousing where the oily tube came from
Do you have the pulse air injection (Emission controls) on your 4.2? There are 2 air hoses that run from the Air cleaner to the CAT and exhaust pipe with a check valve and vacuum controlled air valve. If you run 20 Min and have the problem, with the engine idling, and with the lid off the air cleaner hold your hand over them you can feel the pulsing. If you stick a vacuum gauge into the tubes inside the air cleaner, you should find that they will pull a little vacuum.
There is a great write up on this site... http://home.sprynet.com/~dale02/pulseair.htm
There is a great write up on this site... http://home.sprynet.com/~dale02/pulseair.htm
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