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Bad Smell - Hot Exhaust

smccollamjr

NAXJA Forum User
Location
WV
When towing, I had been getting a nasty smell. Come to find out it was the carpet on the passenger side getting HOT. Previously I had removed the carpet in the cargo area, sprayed it with rubberized undercoating from Advance, and replaced the carpet. On top of the carpet I have a truck bed mat that I cut to fit. In the cargo area close to the back of the seat (passenger side) it looks as though the carpet is burnt or melted in a couple places. So I replaced the converter, mufflet & tailpipe. I haven't towed anything yet, but just with normal driving the area under the rear seat gets really hot. By normal driving I mean highway with no load ~88 degrees outside. Is it normal for it to get that hot?

'96 4.0 5-speed 121k miles
 
By the way, while towing on level ground & down hill the temp stayed under 210, got to about 215 going up hill. Normal driving stays around 200.
 
Thinking back, when I removed the old tailpipe there was a black rim around the end of it. Is that a sign of it running rich? Also, I just changed the plugs. A couple of them were pretty black but the rest looked good. What did that mean. The old ones were autolites, the new ones are champion truck plugs.
 
When was the last time you changed your O2 sensor? It sounds like you could be running rich. Also, your coolant temp sensor (the one on the t stat housing) could be bad causing you to run in open loop mode (rich). How's your mileage? Have you noticed a change lately?

K
 
langer1 said:
o2 sensor, map sensor, leaky injector on 1 or more cylinders, EGR valve stuck.

No egr on '91 up.

K
 
Both O2 sensors have been replaced in the last year. The "Check Engine" light is NOT lit, but it was before I replaced the sensors. It was giving the O2 sensor code.

I've got less than 200 miles on these plugs, so they probably haven't had time get burnt.
 
smccollamjr said:
Both O2 sensors have been replaced in the last year. The "Check Engine" light is NOT lit, but it was before I replaced the sensors. It was giving the O2 sensor code.

I've got less than 200 miles on these plugs, so they probably haven't had time get burnt.
You would not be looking for burnt plugs, you would be looking at the color to find a problem like to much fuel.
How to read plugs http://dodgeram.info/Engine-Gas/SparkPlugs/spkplghnbook.html
 
Last edited:
I finally got a heat shield. The XJ it came from had threaded studs welded to the unibody. My '96 doesn't have the studs. If I drilled through the body and used nuts & bolts to mount it, would that cause a bigger problem? Would the bolts get hot and cause the same problem I've been having?
 
I had similiar problem as yours, ran rich, exhaust got so hot carpet started to steam on pass. side( oh, BTW I have a water leak somewhere), couldn't find the prob for the life of me. I decided to take all vacuum lines off(one at a time) and check them for wear. I put the one back on the MAP and it still ran bad, then I noticed that I had put the line on the screw that sticks down thru the MAP and not on the connector ( NOTE TO SELF: fix leak and get new glasses), reconnectred to connector.....runs fine. I had cleaned the TB and must have installed line wrong when I put it back together....DUH!!
I'd be checking vacuum lines...good luck
 
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