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  1. Hi Moses, thanks for responding. I did a basic compression test and found all 4 cylinders to be right around 120 psi. One thing I noticed is that when I first start the jeep up with a cold motor, I can give it plenty of throttle and it won't start backfiring for approximately 45-60 seconds. After that, it starts to pop under throttle and gets progressively worse as it warms. There is also no lifter noise when first starting it up, but after a couple of minutes when given throttle there is definitely some kind of rattle. I can manually compress the EGR valve while its running and the idle drops, that tells me the valve is functioning properly. The exhaust is very black and sooty, with strong fuel odor. I wish I had pulled the camshaft while I had the timing set off! If I remove the valve cover and measure the upward travel of the valves What type of # should I be looking for?
  2. Hi, I have a '89 Wrangler with the 2.5l. It pops/backfires back up through the intake whenever I give it throttle. There are no vacuum leaks. I have replaced every sensor. I have swapped out the PCM, no change. I have checked fuel pressure, 15 psi. At this point I found excessive play in the distributor when rotating the crank, so I pulled the timing cover and found the chain to be stretched, and the cam sprocket and crank sprocket timing marks were mis-aligned. Aha! I said, and replaced the timing set- I set the crank to #1 TDC on compression, rotated the cam forward so that the marks would line up properly, and installed the new set. After reassembly, I checked the distributor and made sure that it was pointing to 6 o'clock when the timing mark on the cover was at 0 BTDC. I then fired it up, and the issue remains. Backfiring through the intake. Could this be a camshaft or valve issue? What would be the next move?
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