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Post by jeffreylane on Jun 19, 2015 18:43:24 GMT -6
So what I've been working on...... So Crystal ' s YJ decided to give us problems, So I got a chance to start exploring some of the screwed up engineering that is the Jeep YJ. The symptoms...Crystal started driving to work one morning, gave me a call to tell me that is was driving like crap and backfiring out the carb. She parked it and got a ride to work. When I got off work I drove it, and yep, drove like a turd, spittin' and sputtern'...backfiring out the carb and didn't want to stay running.
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Post by jeffreylane on Jun 19, 2015 18:46:43 GMT -6
So I started checking the easy normal stuff... first thing the distrubutor. Now I admit I haven't really been under the hood of this thing much at all, and then only thing done to the motor was adjusting the carb and some plugs. When checking the distributor cap, I found one of the screws in the cap loose and the vacuum advance bolts loose. Fixed those, that had to be the problem.
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Post by jeffreylane on Jun 19, 2015 18:49:01 GMT -6
Nope..... still the same symptoms. so I kept digging. Checked pcv valve. The return, or whatever it's called, the one without the valve in it was almost completely closed up with carbon build up. Cleaned it all put. I bet it will run good now.
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Post by jeffreylane on Jun 19, 2015 18:51:20 GMT -6
Nope. Idled better, but still same symptoms. Well let's check the timing. When I put a light on it, I found t hat the timing was fluctuating 6 degree with the advance plugged off. That's no right. So we did the nutter bypass. Bet it's going to run right now.
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Post by jeffreylane on Jun 19, 2015 18:54:01 GMT -6
Nope.....it now has as much power on 5 cylinders as it did with 6 though. I forgot to mention that I also put a new fuel pump and a new accel coil on it to check those things since we already had them.
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Post by jeffreylane on Jun 19, 2015 18:57:35 GMT -6
Next I started pulling plug wires with a pair of Kleins while running to see where it was missing. #3 was a dead miss. Also it's amazing how far of an arc that accel coil will throw (which traveled through the ground strap back to the hood I was leaning against). Of course plug wire checked out ok, plug was fouled. New plug....no change.
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Post by jeffreylane on Jun 19, 2015 18:59:22 GMT -6
Next, check compression. All looked ok except for #3 which only built to 30#-#35.
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Post by jeffreylane on Jun 19, 2015 19:00:40 GMT -6
Looks like a valve problem. Also checked the exhaust to confirm, and it had the wierd push/pull exhaust effect a bad valve will give.
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Post by Daniel on Jun 19, 2015 19:31:11 GMT -6
I was hoping you'd do the nutter bypass. But hate it's down. Have you checked the valve springs for a collapsed or broken spring on that cylinder?
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Post by Somebody on Jun 19, 2015 19:32:43 GMT -6
Jesus... Went thru more than I could have to diagnose it.. lol
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Post by jeffreylane on Jun 19, 2015 19:33:57 GMT -6
Pulled the valve cover to check things out from the top side. As suspected there was a problem with #3. Lots of play in the rocker arm. The valve valve all the way up where it should be. Pushing down on the push rod, it felt springy. Pulled the push rod out and it was straight. The rest of the rockers felt fine. Looks like a collapsed valve, so off comes the head.
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Post by jeffreylane on Jun 19, 2015 19:37:38 GMT -6
So here is what I find on #3. Looks like more than just a lifter. I sort of figured as much when it didn't pump up any after pouring ATF in the oil.
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Post by jeffreylane on Jun 19, 2015 19:39:46 GMT -6
Dug a little deeper to find the cam had a flat spot on it, so looks like a new cam. There was slack in the timing chain also. One of those, since I'm in here.
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Post by jeffreylane on Jun 19, 2015 19:41:17 GMT -6
So Crystal is bumming rides to work next week we we wait on parts to come in. Here is how it sits now.
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Post by jeffreylane on Jun 19, 2015 19:47:52 GMT -6
So figured we might as well throw a little upgrade at it, so we have a 252 comp cams set on the way with a Double roller timing set, as well as all the gaskets. Would like to have went ahead and did a 4.0 head swap, but the one I have here ended up being cracked, and money is tight with all these unexpected problems lately. So that may come later. We are going to to ahead and do the team rush mod (converting over to larger ford I6 distrubutor) since the little distributors in the 4.2's are bad about arcing off of the terminals inside.
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