Jeep Strokers

It should clear itself after so many miles/ start cycles

I couldn't wait for the light to clear. It was driving me crazy, staring at me. So I removed to pos. battery terminal. I've put 60 miles on it and light is still out.

OK, something wierd happened the other day on the way home from work. I was stuck behind someone going slow in the fast lane. When I saw an opening to get around him,I dropped down to third gear and punched the gas. The engine back fired out of the intake. I let off the gas punched it again and once more it backfired. It hasn't done it since, and I can't get it to do it again. No check engine light, no engine or valve noise, good oil pressure, and it has been running strong and smooth ever since.

It did do this once when the engine was installed. I thought it was because the PCM had to readjust because the battery was removed, and because the cam position sensor wasn't adjusted quite right.

Back fire out of the intake usally means a lean condition, or timing to far advanced. I am due for my 6000 mile oil change, maybe I'll pull the plugs and look at them. I really need to install an AFR gauge.

Any ideals of what could have cause this?

Cam position sensor maybe? I know that if i rotated the sensor on my 2000 to far in either direction it would back fire.

Does sound more like a timing issue.. or a valve held open.

I had the cam sensor adjusted at the dealer with a DRB after I got the stroker installed and running. I haven't moved it since then.

Before I did the 6000 mile oil change, I decided to change the steel valve cover for an aluminum one (clearance issuses with roller rockers. That's another story). And since the valve cover was off, I checked the roller rocker adjustment. They weren't ticking, but the cover was off so why not? I pulled all the plugs to make turning the engine over easier. All the plugs looked good, but since the plugs were out I thought might as well install new ones, they are cheap enough @ $1.35 each. I also changed the #1 fuel injector for an intermittent P0301 code.
So new valve cover is on, rockers adjusted, new #1 fuel injector, and new Autolite plugs. Autismzone only had 4 Champions, so I opted for the Autolites. Drove the Jeep around a bit, and then to my son's soccer practice. Everything seams good. Attempting to leave soccer practice, my Jeep stops running and I get a P0340 code (cam position sensor). I have an extra one at the house, and it's not that far from the soccer fields. So my father in law picks me up, we go back to the house grab the cps, and head back to the Jeep. When I remove the cps, just the top of the sensor, it's in pieces, and the magnet has chewed up the the rotating metal piece inside the cps. So back to the house get more tools and the lower half of the cps. Back at the Jeep the engine is turned until #1 piston is at TDC, tooth pick installed in cps, and cps dropped in and tightened. Engine starts right up, but I still have the P0340 code. It's late so I figured I would take the Jeep to the dealer in the morning to have the cps adjusted with a DRB.
The dealer adjusted the cps and reflashed the computer. Check engine light is out and Jeep is running smooth. But now I have either pre-ignition or detonation under acceleration @ about 2500 rpm. What could be causing this? The only thing I can figure it might be is the plugs, or a bad computer flash from the dealer. I am off tomorrow, so I am going to put the old plugs back in and see what happens.

dwg86 wrote: When I remove the cps, just the top of the sensor, it's in pieces, and the magnet has chewed up the the rotating metal piece inside the cps.

Its not the first time I heard of this happening.

The dealer adjusted the cps and reflashed the computer. Check engine light is out and Jeep is running smooth. But now I have either pre-ignition or detonation under acceleration @ about 2500 rpm. What could be causing this? The only thing I can figure it might be is the plugs, or a bad computer flash from the dealer. I am off tomorrow, so I am going to put the old plugs back in and see what happens.

Could be the flash or the plugs. I don't like to run Champion or autolites for the 2000+ ignition system. NGK. It likes them. What is the heat range of plug you are running? Let us know what happens with the old plugs. Why did the dealer flash the PCM anyhow?

I'll let you what the plug numbers are when I change them. I don't know why the dealer flashed the computer. I thought maybe the flash was to reset the CEL. Maybe it was just put on the invoice so I pay more $$$...

Well, the plugs weren't the problem. #6 plug was almost oil fouled. I looked down the throttle body into the intake and saw plenty of oil. So I was sucking oil through the CCV. Before I installed the aluminum valve cover, I removed the baffles to clean them up. There is a hole on the side of the baffle near the top. I thought it would be a good idea to plug this hole to keep oil from getting sucked up in the CCV. WRONG! The end of the baffle sits low on the valve cover. When I plugged the hole on the side, it made the baffle into a straw, sucking up a lot of oil. With the hole open, its like trying to drink through a straw with a hole in it, doesn't work. So I removed the valve cover, removed the baffles, and the rubber plugs I put in the holes, reinstalled everything, and so far problem solved.

The oxygen sensors only read the amount of oxygen. When oil gets injested into the intake, the O2 sensors only see only low oxygen, and think the engine is running rich. So they lean it out. That is why it was pinging...very lean.

oil vapor also reduces the octane of your fuel by quite a bit.... so. you solved lots of problems at the same time.

Update: Just did 9000 mile oil change. Everthing still good (knock on wood). I'm still using VR1 10w30. I would like to change to synthetic, but not sure what oil has high zinc.

Amsoil is still high Zinc.

Certain Amsoils are still high in Zinc. I think I posted someplace on here which ones. If you search my name and amsoil as a keyword you should find it.

Just an update...12,000 miles and still running good. Still getting 19-20 mpg. Not using any oil between oil changes. I had a check engine light come on the other day. It was a #2 cat code. Probably from my previous problem I had with my homemade valve cover baffles allowing oil to be sucked up through the ccv valve and being sucked into #6 cylinder. The CEL light went out. So my next mod will probably be high flow cats and dual exhaust (1,2,3 cylinders on one side and 4,5,6 on the other side). I'm not sure what mufflers to use. I don't want it to sound like bumble be.

How are you calculating mileage? I hope you aren't using the on board computer to, if your jeep has one.