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4.0 head swap - running rich, missing/knock, fuel in oil, red hot cat

4.0 head swap - running rich, missing/knock, fuel in oil, red hot cat
Yup, Borg Warner cap. With my timing set -10 the .005 over on the gap will only help with a larger spark and a more complete combustion. When I regapped the cat stopped overheating. This "miss/lifter" issue was happening long before I gapped the plugs.


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Lumpy Grits said:
Before you do anything like that. Check your cam lobes.

Take the valve cover off and watch the rockers at idle. Do they all move the same amount??

LG
Click to expand...



What's the best way to do this and not shoot oil all over the place? I tried a while back but the rockers blew oil all over my garage.


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Lay a towel on top of the rockers.
What plugs do you run?
LG
 
Lumpy Grits said:
Before you do anything like that. Check your cam lobes.

Take the valve cover off and watch the rockers at idle. Do they all move the same amount??

LG
Click to expand...



What's the best way to do this and not shoot oil all over the place? I tried a while back but the rockers blew oil all over my garage.


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Last edited:
Please see the edited in link, in my other post.
LG
 
Lumpy Grits said:
Please see the edited in link, in my other post.

LG
Click to expand...



Thanks lumpy, I've read thru those threads. It's not a standard AMC 258 i6 / 4.2l motor. The only thing AMC 258 i6 / 4.2l left is the block, rockers and flywheel. The 4.0 doesn't have a spark arc issue like the tiny cap on the AMC 258 i6 / 4.2l . But I did everything this upgrade has with the exception of the larger cap.

I'm 100% certain this noise is not being caused from any spark or fuel issue.


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The info under your site name is a separate deal, from the database.
I do not see your info in the database section. But then some dayz I can't find my mind, either-LOL
LG
 
Lumpy Grits said:
The info under your site name is a separate deal, from the database.

I do not see your info in the database section. But then some dayz I can't find my mind either-LOL

LG
Click to expand...



Hmmm... I'll look into that. I was having trouble loading photos. It may have got jacked up or something.


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Joebronco said:
Ok, bumped down with 4 washers and its smoother for sure. But still rough after it hits closed loop. Still missing.


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Listened to video and agree it sounds mechanical and not electrical.

Your closed loop comment reminded me. What brand O2 are you running? After warm up, the PCM relies heavily on the first O2 Sensor. I had a Bosch at first and read a lot of negatives from anyone with a 4.0. Got the OEM NGK and it made a significant difference. Can join us on jeepstrokers for more.
 
Long time no post... got her running fine. Turns out it was the lifter.

e65d7834ca90eab22c156b2efe56ce63.jpg



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