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-   -   Jeep cutting power... Please Help! (http://www.wranglerforum.com/f210/jeep-cutting-power-please-help-249808.html)

cfarlow89 06-16-2013 08:08 PM

Jeep cutting power... Please Help!
 
My 99 Wrangler is reading a CEL code for a Cyl 6 misfire. When I drive it either accelerating or just going a steady speed down the highway, the engine will cut power for a split second and the Jeep will "jump" or "pull back." The CEL was on for about a month before I started having the problem.

I just did a tune up about a month ago- new distributor (and all the parts with it), wires, spark plugs, coil. So I'm pretty sure my problem isn't there. I thought it may be a bad injector, so I replaced the injector for cyl 6 and ran Seafoam through the gas tank.

I've replaced the TPS and completely dissembled and cleaned the throttle body, AIC, and ran throttle body cleaner through the throttle body intake. I also cleaned my air intake filter.

I am completely out of ideas. I've tried 2 different TPS's also, because I read that a lot of people had problems with them out of the box. Someone please help me before I light the thing on fire!! :banghead:

Big Sarge 06-16-2013 08:11 PM

CPS could also cause the cutting off resulting in jerking. May want to try that before setting it on fire. LOL

cfarlow89 06-16-2013 08:20 PM

lol OK. I've noticed that the light that comes on when you're supposed to shift up isn't coming on now. Any chance it's something electrical? I just don't understand why it would through a CEL code for a misfire on Cyl 6 if it's not something directly related to that cylinder.

Big Sarge 06-16-2013 08:29 PM

Quote:

Originally Posted by cfarlow89 (Post 3867286)
lol OK. I've noticed that the light that comes on when you're supposed to shift up isn't coming on now. Any chance it's something electrical? I just don't understand why it would through a CEL code for a misfire on Cyl 6 if it's not something directly related to that cylinder.

Do the self test on the cluster to make sure the shift light works. To do that you hold down the trip reset button then turn the key to the on position (do not start the jeep) then release the trip reset and watch the cluster. It will move all the gauges and illuminate most all the lights at different times. That will at least let you know if that bulb is good or not. The CPS (in your case you have two) crank position sensor and cam position sensor can both cause the engine to do weird things. I have no personal experience of it triggering just a #6 misfire but I would think its possible.

cfarlow89 06-16-2013 08:32 PM

OK. Is there a way to test the CPS before I replace it/them. Also, can you think of anything else it might be if not the CPS?

Thanks for the help so far... :)

Jerry Bransford 06-16-2013 08:36 PM

Attach a fuel pressure gauge to the Schraeder test port valve on the fuel rail & verify your fuel pump is putting out the factory specified 49 psi or at least close to it.

Big Sarge 06-16-2013 08:38 PM

Quote:

Originally Posted by cfarlow89 (Post 3867347)
OK. Is there a way to test the CPS before I replace it/them. Also, can you think of anything else it might be if not the CPS?

Thanks for the help so far... :)

The crankshaft position sensor you could try taking off and cleaning. They can get a carbon like build up on them. Not sure about the camshaft sensor though. I'm unaware of an ohms test or something for the sensors but as it sounds like an intermittent problem it may be hard to test like that anyways. I have been chasing a somewhat similar problem on my 2.5 and have changed almost every sensor as well as plugs, wires, coil, d cap, rotor, coil to no avail. Recently changed the o2 sensor and getting a new CAT this week. We will see if it fixes it.

cfarlow89 06-17-2013 04:20 PM

Ok. Well i'm going to check the fuel pressure in a little while. If that's not the problem at least I can rule out a pump issue. Will clean/replace crank position sensor. I haven;t checked the O2 sensors yet... didn't seem like that would be it, but maybe.. idk anymore......

cfarlow89 06-17-2013 04:21 PM

Any chance it might just be a shorted wire?

Jerry Bransford 06-17-2013 05:34 PM

Quote:

Originally Posted by cfarlow89 (Post 3870149)
Any chance it might just be a shorted wire?

Slim.

cfarlow89 06-17-2013 08:05 PM

How long will it take the computer to recognize and re calibrate to the new TPS? I went back to the auto parts store and had them run the CEL code again. Turns out the misfire code for cyl 6 went away.

Apparently I fixed it without realizing it, since another code had caused the CEL to stay on. When they ran it this time it came up as P0123 (Throttle Position/Pedal Sensor). Replaced the TPS again and the problem with it cutting power seems to be getting better. It's only doing it about 1/8 as often as it was and seems to be a softer jump.

I've driven it for about 30 minutes since and cranked the engine 10 times or so, as well as disconnecting the battery a couple times and leaving off for 30 sec or so. Is there a possibility i fixed the problem, and the CEL will go of after the computer fully re calibrates?

:confused:

cfarlow89 06-17-2013 08:06 PM

Oh and btw my fuel pressure is at 48 PSI, so i think I'm good there. Crank position sensor seems clean- haven't replaced yet. The other CPS was replaced when I did the ignition system tune up.

Big Sarge 06-17-2013 08:15 PM

Sounds like its improving! The parts house TPS sensors are notorious for not acting right in our jeeps. I personally have not had an issue but many many on here have. Have the parts store read and erase your codes to get the light off. Unhooking the battery won't do it normally. Worst case with the TPS you will need to get one from the dealership.

cfarlow89 06-18-2013 06:17 PM

Well I drove for about 2 hours today- smooth as butter. Apparently the third TPS fixed the problem. I went with a different brand "Duralast" instead of "BWD". It was my last resort before shelling out the $130 the dealership wanted for the MOPAR one. lol

The light till won't go off. I unhooked the battery cables. Going to leave them off for 24 hours. I guess it doesn't really matter as long as the Jeep is running correctly, but it's still annoying seeing that light on my dash all the time.

Big Sarge 06-18-2013 06:22 PM

Disconnecting the battery normally will not turn off the CEL. You can go to where you bought the sensor and they can hook up the scan tool and turn it off for you.

Glad you got it taken care of

Jerry Bransford 06-18-2013 06:31 PM

Quote:

Originally Posted by Big Sarge (Post 3874560)
Disconnecting the battery normally will not turn off the CEL. You can go to where you bought the sensor and they can hook up the scan tool and turn it off for you.

Glad you got it taken care of

Disconnecting the battery for 2 minutes will clear any CEL. At least until the problem occurs and again and re-triggers the CEL.

Big Sarge 06-18-2013 06:35 PM

Quote:

Originally Posted by Jerry Bransford (Post 3874590)
Disconnecting the battery for 2 minutes will clear any CEL. At least until the problem occurs and again and re-triggers the CEL.

Yet again I learned something from Jerry! I stand corrected.


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