Mechanics

MISS IN ENGINE 91

1991 Jeep Wrangler • 4 cylinder 4WD Manual • 129,000 miles

I have a 91 Jeep wrangler 4 cylinder the #1 cylinder is not firing even w/new plug, wire, distributor cap and roter bug w/ plug out it seem to get fire as well as blow attiquite compression w/new plug and wire (both good) it still has a bad miss. Can you suggest anything Thanks
Avatar
Dutcher5
March 2, 2011.




Just trying to help,

Not a paid mechanic, I can just about make any CJ repair blindfolded, I have answered most of the questions in the CJ 5 & 7 Forums for the last 2 years.

I know little about Wranglers and computer stuff--I do understand engines!

How have you come to the conclusion, "ITS # 4? Did you pull that wire while it was running and there was no change in the skip?

Have you performed a Compression test on all 4? Results?

Like I said do not know Wranglers--I'm guessing Fuel Injection?

What about pulling the Distributor cap, grab the shaft. Is there EXCESSIVE WOBBLE IN IT?

Any chance the distributor got moved and it's timing is off?

Run it in PITCH BLACK DARKNESS. Any Sparks-A-Jumpin' from the wires etc?

Did this just start? How bad is it?

Compare all plugs after, lets say, a 10 mile drive---Bottom of #4 look as though it's Shootin' in Moisture (Head gasket leak)?

On my 1946 Willys, #3 started skipping. Then a tapping sound a bit later. "Willy" has always been good to me, so I fix him as quick as I can. The tapping was making me sick, really fast. The skip was not severe.

I snatched the pan, and replaced the rod bearings. Still tapping

I pulled the head and #3 Piston was pitted on the entire top, then on the edge you could see part of the top ring had pushed thru to the top, maybe 1/2 inch of ring. It was being pounded into the top of the piston (thank goodness it was only about.020" actually hitting the head. Head survived)

What had happened was, I had a coolant leak into #3 (head gasket)--This caused the plug to "Detonate" every time it came up (The Sandblast looking pitting all over). Sorta like a "Lightening Bolt" sheared the top cast iron ring, 1/2" from the original gap. And some how it poked a perfect teenie-weenie rectangular hole in the edge of the piston, then jumped on top.

I had replaced the rod bearings. Now did 4 new pistons, 'cause I had to buy a full set anyway. And a head gasket.

Fortunately, "Willy" is like a big Ole Lawnmower. Everything including the pan was EZ to get to, and off!

I really hope you come back and tell me your wire is jumping fire!

Hit me with results

The Medic


Tiny
CJ MEDEVAC
Mar 2, 2011.
This one didn't come thru
AD


Tiny
CJ MEDEVAC
Mar 2, 2011.

AD