Jeep 2.7 runnin rough

IFSchamp

New Member
Joined
May 6, 2005
Location
durham
I recently ran across your forum here and have a question about a friends jeep. So this is what she has

1995 jeep wrangler (with leaf springs) I think its a xj but not shure, that is acting like its running on 3 cylinders. The motor is actually a 96 if that means anything. one plug, i beleive its cylinder #4 has some oil/unburned feul on it although there is no sign of oil leaking from the head nor is there any oil being burned off. Is her head gasket slowly going or is there a fuel mixture or timming problem? any idears
 
If it is a '95 wrangler, it is a YJ. I would try swapping plug wires between 2 cylinders to see if the misfire follows it. If not, It could be the plug itself, the cap, rotor, or timing. When was the last tune up done.? I think she would be money ahead to spend the $100 to do a full tune up and see where it is from there.
As for unburnt fuel or oil on the plug, I would think worn rings or a stuck valve before a head gasket. I would think with a head gasket blown, you would be getting coolant into the combustion chambers and some smoke from the tailpipe.
 
Could be a bad plug, wire or distributer. The fuel you see, is on the electrodes right? (the part that goes in the engine). If the Head Gasket was bad you'd be burning coolant or oil but the cyl would still fire. Check the oil and see if there is coolant in it and check the coolant and see if it looks like Chocolate milk. If either of these is current, you have a blown head gasket.
 
thanks for the advice, i spoke with her last night and we are going to do some troubleshooting today. she claims that there is an exhaust leak around the cat-converter. could the loss in backpressure cause oil to sneak up past the rings on that #4 cylinder?

timming question: When i check the timming on my yota i have to cancel the advance by crossing wires on the diagnostics module. if i wanted to check the timmig on the 2.7 how would i cancel the advance?

Thanks for taking the time to help me out
jp
 
The loss in back pressure would'nt affect the cyl in any way. Just makes it louder. As for your timing? I unfortunatly have no experience timing Jeeps. Only thing I've timed is old Yota carb motor and I just disconnected the vacuum advance. Same as my even older Ford I had in High school. Sorry I couldn't be of more help. I kinda doubt it's a timing problem though. That would just make the engine knock and ping and not have as much power.

Try Taking the No 4 plug out, plug it into the wire and touch the threads to the block and crank it over. (Don't hold on to it though or it'll shock the crap outta you) Look real close to see if you're getting spark.
 
i'll check for the spark. Thats where i will start, from there i will check the timming, as i don't have much experience working on jeeps and can't judge the correct engine tone, ex. i hear that the 4.0 is bulletproof but tends to run rough. If that doesn't pan out i will buy a compression tester. Thanks for the ideas guys, i'm helping out a friend who doesn't have alot of $ and loves to run her jeep offroad and as a D.D :driver:
jp
 
worked on it ALL day yesterday

timming was fine
plenty of spark to cylinder#4
found out its a 2.4 litre
the problem was in the muffler. it was choked up and killing the preformance of the motor. so today a new muffler and tailpipe go on.
 
for the record, it its a four cylinder it would be a 2.5l , if its a 6 cyl it would be a 4.0l. the timing on the 2.5 is non adjustable. also if the muffler is clogged up it is probably full of substrate out of the catalytic converter. be careful replacing the rest of the components w/o checking this first or you will likely have to replace those items again very soon. anyway i noticed you are in durahm, i have a reputable exhaust business and also have a store there in durham on hillsborough rd. MONRO MUFFLER AND SERVICE. bring it on down on monday, they will tell you what is wrong for sure and not charge you for the estimate. better to fix it right the first time or be prepared to do it again!!! anyway my shop has a best price guarantee and all of my mufflers are warrantied for life and the cat is warranted for 5 years. not against trail damage though!
hope this helps.
 
Thanks for the advice. its not my jeep (a friends) but i will let her know of your establishment
 
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