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What's wrong with MeJ?


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I have an 87 comanche, 4.0 5spd. Lately it has started to miss or sputter when I push the accelerator DOWN like in 3 and 4 when I want to run the speed up. It will just do nothing and start to act like I'm running out of fuel. I've owned it for just over a year. Over the last winter when it was about -10F I started it and it revved HIGH and I couldn't get the engine to settle down until I GUESSED which TB harness to unplug. It was the one on the right, TPS? I hadn't had any problems since then, (I plugged it back in again).

 

This problem started off as, I would be pulling a hill and all of the sudden I would get a power surge. Not so much of a Miss, just like, "here's some extra horsey's for ya."

 

Now it just about dies. I replaced the plugs, wires, and distributor cap last fall. Now I removed the catalytic converter and installed a 2.5" muffler instead. I just changed the fuel and air filter too. It seems to start as well as any other Jeep. It takes a while to crank, but if I tap the accel once it starts quicker.

 

I've read on here that the CPS may cause this, but I wonder if the TPS could be at fault too.

 

 

Any suggestions would be appreciated. Thank you.

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Well also the cps will be an issue if you have long crank times. Sensors are a bear to pinpoint. They are expensive and hard to track down. Search Naxja and Jeepsunlimited for info too, lots of XJ's on there with the same running gear, may find some insight as to the problem.

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well... hows the idle? what are you running for gas? clean your airfilter? make sure to check all fluids and put some engine stop leak (marvel mystery oil works great) and injector cleaner. should take care of the problem. plus if it don't you still get all the benefits of what you put in and if you put in a new cps and it don't take care of the problem your outta some sweet cash

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Check the EGR valve and transducer operation.

 

I agree, look at your EGR.

 

CW

 

I picked up a transducer, nothing like the Chilton manual shows. IS the transducer what threads into the intake manifold? This looks similar, but not identical. OR is the transducer on the fender wall with a wiring harness attached? According to the manual a vacuum line runs DIRECTLY from the EGR to the Transducer. Mine goes to a little block of vacuum lines.

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Thank you very much fiatslug.

 

My EGR diaphragm is kaput. I went through the tests and when it came to directly hooking the vacuum line to the EGR, it did nothing to the idle. I can push it in with my finger and affect the idle. Are these things really $166 ?

 

NOTE:

 

I have NO transducer. I only have the solenoid. was there an update? The solenoid has the vac line and the output line, the rubber fitting could accomadate 2 outputs, but the end one has been blocked off.

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btt

NOTE:

I have NO transducer. I only have the solenoid. was there an update? The solenoid has the vac line and the output line, the rubber fitting could accomadate 2 outputs, but the end one has been blocked off.

 

Anyone out there with an '87 4.0L that can help? The above was from the '89 FSM (correction to original post). I know '88, '89, and '90s had a transducer on the EGR and all vacuum lines are as shown in the diagrams, only two lines to the solenoid. Is the rest of the vacuum harness as above or did a previous owner modify it?

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