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-   -   wj acceleration problems (http://www.jeepgarage.org/f196/wj-acceleration-problems-18146.html)

patriotmfd 01-30-2011 09:44 AM

wj acceleration problems
 
02 WJ 4.7L with 90k miles engine problems or transmission problems… starts fine , good low end power but as you accelerate power dies off - dash lights blink trans light blinks “trans over heat” light comes on…no codes through.. I installed new plugs and air filter no change. condition does not seam to happen all the time. Also just did trans fluid and filters. Still does not want to power up any suggestion appreciated

StoneCold 01-30-2011 09:50 AM

Re: wj acceleration problems
 
What trans fluid did you use and how much did you put in? Could you have knocked a sensor when you changing the filter?

Frango100 01-30-2011 10:01 AM

Re: wj acceleration problems
 
Did you have those problems before changing plugs and fluids? Does it feel like the tranny/torque converter can not transfer the torque, or does it feel like the engine doesn't have enough power? I had some similar problem on my WJ. It was driving normally, but when accelerating it was lacking power. After changing the fuel filter/pressure regulator my problem was solved. Strange though that you also have the TRANS OVERHEAT light on. Is this light on all the time?

patriotmfd 01-30-2011 10:18 AM

Re: wj acceleration problems
 
This problem was happening before the Trans fluid change; I used ATF+4 fluids as per spec. And it feels to me like it is some kind of computer problem like a sensor is telling the unit to go to survival mode and limp home

Frango100 01-30-2011 11:20 AM

Re: wj acceleration problems
 
Is the tranny not changing gears? You probably have to go to some place where they can read the tranny faults. It can be an input/output sensor problem or some other senor in the tranny.

patriotmfd 01-30-2011 11:33 AM

Re: wj acceleration problems
 
Trans changes gears fine.. just came back fron auto store and if i accerelate real easy it runs fine, as soon as i ask it to get up an go it stumbles if i keep accerelating it would probley stall when i baby it it will act normal and i can get it up to 60mph I am checking fuel rail pressure next thanks for the help

patriotmfd 01-30-2011 03:00 PM

Re: wj acceleration problems
 
just changed the throttle position sensor no luck. still will only run to anbout 1/2 throttle and than breaks up error code 0300 "all cylinders misfire" ananyone been here please help

Frango100 01-30-2011 04:00 PM

Re: wj acceleration problems
 
Not sure if this could have to do with a cam or crankshaft sensor.

patriotmfd 01-30-2011 09:49 PM

Re: wj acceleration problems
 
2002 jeep Grand Cherokee, Limited Silver with Black leather oil changed every 3000, K wife’s car babied been on the beach a couple of times but 99 percent a commuter car to and from work a (5 mile commute)

Started out the coldest day of the year 5 degrees. jeep gave wife problems did not want to get her to work. had code 0203 number 3 cylinder injector failure. I took # 3 injector out and switched it with number 4 injector no problem - no code but jeep still does not want to run pass ˝ throttle if you baby it will run as soon as you push it quits.

Day two Replaced spark plugs with Mopar copper core # Mopar® P/N SPRC12MCC4
No change still quits above 50% throttle position
Pass ˝ throttle if you baby it will run as soon as you push it quits


Day three had Trans code over heat so I changed the Trans fluid with ATF+4 fluid and both filters took for test run code 0300 “all cylinder misfire “
No change still quits above 50% throttle position
Pass ˝ throttle if you baby it will run as soon as you push it quits


Day four replaced throttle body position sensor no change to performance
Still quits above 50% throttle position “all cylinder misfire”
Pass ˝ throttle if you baby it will run as soon as you push it quits

Day four replaced manifold air sensor
No change to performance
Still quits above 50% throttle position “all cylinder misfire”
Pass ˝ throttle if you baby it will run as soon as you push it quits. If you turn off key rough idle goes away but as soon as you push it pass 50% accelerator miss returns it will run a low speed all day long but as soon as you ask it to perform it gets all choked up a quits

Does mopar have a shrink I can sent this unit too because I am at my wits end

cheapjeep 01-31-2011 07:46 AM

Re: wj acceleration problems
 
I would check the fuel pressure at the rail and if low change the filter/regulator like Frango did.

patriotmfd 01-31-2011 07:56 AM

Re: wj acceleration problems
 
Thanks I did check fuel pressure at rail and it was 50 psig and held for quite a while so I don't think that is the problem…. I also do not think it is the trans because the miss accrues in neutral when the accelerator is pushed pass 3000rpm runs fine up to 3000rpm than stumbles if I shut it off and restart the miss is gone until I accelerate past 3000k.

patriotmfd 01-31-2011 10:11 AM

Re: wj acceleration problems
 
I am down to three item’s either the crank position sensor CPS or the engine control module ECM unit is malfunctioning or possibly the catalytic convertor is somehow restricted. The CPS I have purchased from Mopar but I can not see it and it appears like a difficult job… has anyone had experience doing this replacement? (Most problems with the CPS seam to be they fail when the car heats up an restores after cool down) my problem is fairly consistent.

All help is appreciated thanks


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