Help!, My 'manche quit running

[Automan2164]

Have you checked the ground from the block to the chassis?

 

Rob

[HOrnbrod]

Surely your local j/y has a few 91-96 (I think) XJ's you can get one from. Hmmm .... the 5 speed and auto might use a different unit. Robert

 

They do use a different ECU p/n, but any 91-95 4.0L OBDI ECU will work for testing purposes. The auto tranny ECU may idle a bit higher.

 

Also recommend a yard unit, or "borrow" one for test purposes. Just do not get one from a donor with the factory security system.

[comanche12]

check O2S

[JACKED88]

Just curious ..... prior to your current problem, have you done any other work on it recently? If so, what?

 

Why do I ask? ..... My son has a 500+/- hp stroker in his 95 GMC Yukon. After blowing up three 4L60 trans we decided to replace it with a built 4L80. We fired it up, filled the trans with fluid and away we went ..... for about 2 miles before the engine quit running.

Long story short, while replacing the trans and doing the additional wiring for his Optishift transmission controller we missed seeing that a couple of his FAST EZ-EFI harness wires were touching the header.

 

Sometimes it's the little things that come back to haunt us.

[Jerry Forrester]

I'm so upset with that black POS I didn't touch it yesterday. Devoted all my time to the Studebaker. Will probably do the same today.

 

No recent repair work had been done. Other than gas and one quart of oil, nothing was done in the last 3500 miles.

How can a person go from loving a 'manche one week and hating it the next?

 

As far as the cat. goes, I've never had one to stop up all of a sudden. The 'manche went from running perfect to not running in a matter two minutes (the time it takes for a traffic light to cycle).

 

I check the fuel mileage with every tank, it always gets between 17.5 and 18 MPG right up to when it stopped running. Has 150 miles on this tank of gas.

 

I think I'm gonna let it set until Monday, then start in on it again.

thanks for all the suggestions, keep 'em coming.

Jerry

[Automan2164]

Have you checked the ground from the block to the chassis?

 

Rob

[JACKED88]

At this point I don't blame you. Sometimes it's better to just walk away for a while before it really pisses you off.

 

I've got a 1991 E250 Club Wagon van with a 7.5 / 460ci that I haven't registered for almost 9 years. (2003) I quit driving it after burning up the torque converter and ultimately the transmission. Note to self .... DO NOT TOW 23' CHRIS CRAFT THROUGH HILL COUNTRY IN OVERDRIVE!!! Anyway, I replaced the trans with one out of a 97 truck. I was told by a trans shop that other than needing to swap the linkage it would work fine. Wrong!!! After swapping the linkage and installing it, unlike my 91 trans the 97 model doesn't have a speedo gear on the output shaft. Apparently sometime prior to 97 Ford went electronic and put the speed sensor in the rear axle. Even so, up until a year ago I used to slowly drive it around the block or just up to the store every now and then just to make sure it'll still run. Not having a speedo the shift points are a little erratic hence the reason I don't drive it much.

About 6 months ago I charged the battery and tried to start it. Wouldn't start. Switched over to the auxiliary tank and it started. The main tank fuel pump had quit working. I replaced it and everything was fine. No more than a month later the auxiliary tank pump quit working so I replaced it too. Again everything was fine till a couple of months ago. It would run fine and then all of a sudden start acting like it was starving for fuel to the point of dying now and then. If I let it sit for a few minutes it would start and run fine for a while. Then it would repeat the problem. When I replaced the first fuel pump I also replaced the fuel filter so I knew that wasn't the problem. As luck would have it, the third high pressure in line fuel pump quit working. I replaced the pump and tried to start it. Wouldn't start. Now what??? Within the past 6 months I've replaced all three fuel pumps and the filter. Not only did I replace the two in tank pumps, I replaced the entire assemblies. (pump and sending unit assemblies) To this day I still can't get it to start. I've done everything I can think of with no results. I refuse to think both of the new tank pumps have quit working yet I can't hear either of them coming on. I've replaced the pump relays with no results. That was over a month ago and I haven't looked at it since.

 

So ..... as you can see your not alone. I'm in the same boat as you are. Had I not walked away I was threatening to throw a molotov cocktail at it. :fs1: (In which would have been a real shame considering the van only has 97,000 miles on it and other than having the wrong trans and this new problem it's in really good condition)

 

As for the transmission, I haven't really needed the van nor have I been able to afford another transmission for it. Why have I kept it all these years? Because I like it and it's in too good of physical condition to let go. That and I couldn't get what I think it's worth with the wrong/improperly working transmission in it.

 

 

Thought this story might make you feel better.

 

Your Manche isn't a POS. It's just being stubborn. (like most of their owners) :wall: LOL!!!

[Jerry Forrester]

I think I'm gonna let it set until Monday, then start in on it again.

thanks for all the suggestions, keep 'em coming.

Jerry

 

Okay, I lied. I wasn't able to let him sit. Several guys around here have told me that they thought I had a bad reman. distributor. I talked my guy at O'Rileys into letting me return the reman. dist. and selling me a new dist. The new dist. comes with a cap and rotor, (I had to buy the cap and rotor for the reman. unit separate), he let me return them too. :banana:

I installed the NEW dist. Fri. afternoon. Guess what. won't run!

Have any of you guys got an ECM to sell me cheap? Remember, it's a '91 5 speed.

There's a used one on the bay right now for $60, free shipping. He claims it came out of a running '91 Comanche. He'll accept returns but I'll have to pay the shipping back to him. Sounds like a good deal. He has almost 4000 sales and a 100% feedback rating, but I would trust a guy on this forum more.

BTY, I have almost 1200 sales and a 100% feedback so I know how hard it is to keep a 100% rating. Sometimes you have to do some crazy stuff to make 100% of your customers happy.

Jerry

[HOrnbrod]

Get the ECU. That is a good deal.

[deziped]

Pull the IAC and shoot a 1/4 can carb cleaner in the hole and let it sit for 10 minutes. Blow a little air through the hole Reinstall IAC and crank it over. If it starts it will probally idle high until exess gas or anything dumped into throttle body is burnt. While you have the IAC out check it to see if it is working properly.

[HOrnbrod]

Pull the IAC and shoot a 1/4 can carb cleaner in the hole and let it sit for 10 minutes. Blow a little air through the hole Reinstall IAC and crank it over. If it starts it will probally idle high until exess gas or anything dumped into throttle body is burnt. While you have the IAC out check it to see if it is working properly.

 

No IAC in an HO.

[deziped]

Well Team Cherokee sells IAC"s (Speed controllers/steppers) for 91 - 97 Cherokees & 88- 90 also, with different part numbers for them. I'm not familiar with 91 up XJ or MJ vehicles so I kinda rely on what companys are selling for some of my info. Recently read an article where a 98 was being supercharged and modifications had to be made to clear th IAC on the 4.0. If you'd like to further enlighten me, I'm listening.

[HOrnbrod]

My error, you're right of course. Was thinking of the Renix idle stepper motor. :doh:

[Jerry Forrester]

Get the ECU. That is a good deal.

The used ECU came in today.

Had it installed about 15 minutes after the UPS guy left.

Still won't run! :mad: :help:

[Jerry Forrester]

Pull the IAC and shoot a 1/4 can carb cleaner in the hole and let it sit for 10 minutes. Blow a little air through the hole Reinstall IAC and crank it over. If it starts it will probally idle high until exess gas or anything dumped into throttle body is burnt. While you have the IAC out check it to see if it is working properly.

Thanks deziped.

I'll pick up a can of carb. cleaner on my way to the shop tomorrow morning and try that.

 

 

I don't think I need to run a compression test because I have a hell-of-a vacuum pull through the throttle body. But because several people have asked me if I ran a compression test, I was going to run one. Got my old military surplus tester out (been using it since the early sixties) and find I don't have the long reach adapter to screw into the spark plug holes. I'll borrow one from my friend tomorrow and do the compression test. I'll let you know the results.

Jerry

[Boots]

Occasionally mine won't start and just keeps cranking. If I unplug/replugin the CPS and wiggle the wires around it will fire right up. This is on a renix though...

[JACKED88]

Pull the IAC and shoot a 1/4 can carb cleaner in the hole and let it sit for 10 minutes. Blow a little air through the hole Reinstall IAC and crank it over. If it starts it will probally idle high until exess gas or anything dumped into throttle body is burnt. While you have the IAC out check it to see if it is working properly.

Thanks deziped.

I'll pick up a can of carb. cleaner on my way to the shop tomorrow morning and try that.

Knowing you've already replaced the distributor and coil but still claim to have a week/yellow spark, pick up a new coil wire while your there.

[87Warrior]

Wow, most of the go-to items have already been addressed here.

 

Has the battery been tested? My folks XJ would not start with a bad battery (even though it would crank). The computers in these things will get mighty confused with a weak/dying/dead battery. The orange spark you are getting is what has me the most concerned, as you know it should be blue.

 

It also sounds like you have tried a few fuels down the TB. Might try pulling the plugs and cranking it with the fuel pump relay pulled. In an attempt to blow anything out of the cylinders. Replace with new plugs.

 

Might be worth it to drain the tank and put in some fresh fuel. Who knows, maybe some water got in the tank.

[Jerry Forrester]

Pull the IAC and shoot a 1/4 can carb cleaner in the hole and let it sit for 10 minutes. Blow a little air through the hole Reinstall IAC and crank it over. If it starts it will probally idle high until exess gas or anything dumped into throttle body is burnt. While you have the IAC out check it to see if it is working properly.

 

Thanks, tried it and it still won't run.

[Jerry Forrester]

Wow, most of the go-to items have already been addressed here.

 

Has the battery been tested? My folks XJ would not start with a bad battery (even though it would crank). The computers in these things will get mighty confused with a weak/dying/dead battery. The orange spark you are getting is what has me the most concerned, as you know it should be blue..

 

The battery is strong, less than a year old. But of course with all this cranking and no running it was getting a little low. But I have a good charger with the boost feature so that's no problem.

 

 

It also sounds like you have tried a few fuels down the TB. Might try pulling the plugs and cranking it with the fuel pump relay pulled. In an attempt to blow anything out of the cylinders. Replace with new plugs.

 

Might be worth it to drain the tank and put in some fresh fuel. Who knows, maybe some water got in the tank.

 

I have narrowed it down to electrics, it's not a fuel problem.

I have all the plugs out of it now to releave the stress all the cranking was putting on the starter. Don't wanna have to buy a new starter too on top of all the other stuff.

thanks Jerry

[Jerry Forrester]

When I borrowed the noid light from my buddy, I checked only one injector's pulse and it had pulse.

 

I borrowed it again and checked all the injector feeds.

Got pulse on 2,3 and 6.

Nothing on 1,4 and 5.

Hooked the remote starter button up so I won't have to rely on someone else's interpretation of what is happening under the hood while I am cranking the engine over.

At this point in time, I have the plugs out and the cap and rotor off.

I spin the engine and check the spark coming out of the coil wire.

I get two sparks (yellow), then a long pause, then two sparks, then a long pause. In other words, it's firing only two times per distributor revolution.

I reinstall the cap and rotor and check the spark coming out of the distributor cap. I'm getting spark (yellow) out of terminals four and one. The funny (as if anything about this could be construed as funny) part is, the spark from number one terminal is a double spark and the spark from the number four terminal is a single spark.

 

I have tried both ECM's and am getting the same exact results from both of them.

 

So what we have now is,

No pulse for injectors 1, 4, and 5.

No spark for plugs 5, 3, 6, and 2.

Weak yellow spark for plugs 1 and 4.

 

I'm going back to the beginning.

The CPS.

The Haynes manual says to check continuity between terminal A and B on the CPS plug, if it is bad it will be closed. There are three pins in the CPS plug and NO A or B. But there is no continuity between any of the three pins. That is supposed to mean the CPS is good. (Remember, this is at the start of this fiasco.)

I bought a new CPS and installed it. Wouldn't run.

A couple of days ago I checked the 'new' CPS I had installed. It shows continuity between two of the three terminals. Does that mean I have a bad 'new' CPS?

Yesterday I traded that 'new' CPS for another new CPS.

That's as far as I have gotten so far.

I'll have more to report later.

Thanks for all the help. And please keep it coming.

Jerry

[Jerry Forrester]

Oh yeah, I have checked the compression.

Ranges from 110 to 125 lbs.

Not ideal, but probably what one would expect from a 257,000 mile 4.0.

I also have the valve cover off to check the movement of the rockers. Everything there looks good.

 

I have never seen a Jeep flywheel that triggers a CPS. What does it look like? Is there something there that could be causing this problem?

I'm grasping at straws here now.

Jerry

[87Warrior]

No picture but a diagram for the HO flywheel. The Renix era flywheel is notched all the way around.

 

On this Jeep, the signal the PCM uses to fire the coil comes from the Crank sensor. There are three sets of four notches on the six-cylinder flywheel. The Cam Sensor in the distributor tells the PCM which cylinder is #1, and the trailing edge of notch number four in each group of notches on the flywheel (read by the Crank Sensor) tells the PCM that the cylinder in question is at 4 degrees Before Top Dead Center (BTDC). Since it knows where #1 and #6 are based on Cam sensor input, it can use the Crank Sensor input figure out which cylinder is which to synchronize injector pulse.

Reference: http://www.askamechanic.info/askamech2/ ... iew/48/47/

 

That article also made a mention of the ASD Relay (Automatic Shut Down) as a possible cause of no start.

 

Have you tried to pull any engine codes from your Jeep? Turn the key on three times (off-on-off-on-off-on) and count the series of Check Engine light flashes and compare with corresponding code numbers. Don has a nice write up explaining this procedure: viewtopic.php?f=9&t=29857

 

Sounds like the Haynes manual is getting the Renix and HO CPS test mixed up. 4.0 HO CPS testing: http://www.cherokeeforum.com/f51/testing-cps-5563/

[JeffN]

That gets me thinking, does the distributor you put in have the wrong tone ring in it, I didn't read back to see if yours was a renix or an HO but they could have given you the wrong distributor that has the others timing setup in it.

The thing that got me thinking about it was we have a 2002 grand cherokee in the shop that the customer could never get to start, he got it for a song and the p.o. could never get it to run after the install of a new engine.

After comparing a know good cam/crank waveform we noticed ours looked nothing like what it should. Figured out the p.o. had put in a 2008 engine that used a different tonewheel on the cam and crank. We put the proper tonewheel on the cam and that waveform went right to what it should be, tjhe new owner ran out of cash for us to pull the motor and finish the crank repair and had it towed out.

[Jerry Forrester]

No picture but a diagram for the HO flywheel.

Thanks for the diagram and the pic. There doesn't look like there's anything with the flywheel that can cause this problem.

 

 

That article also made a mention of the ASD Relay (Automatic Shut Down) as a possible cause of no start.

Is there an ASD on my '91 4.0? How do I find it and how do I check it?

 

Have you tried to pull any engine codes from your Jeep?

I checked the codes by turning the ign. switch on three times and got an eleven and a fifty four. That's the CSS and CPS. I have replaced both of those with new items. I then disconnected the battery for ten minutes to erased the codes. Now all I get when I check the codes is the code twelve that starts the sequence and code fifty five to end the sequence.

 

Sounds like the Haynes manual is getting the Renix and HO CPS test mixed up. 4.0 HO CPS testing: http://www.cherokeeforum.com/f51/testing-cps-5563/

 

That reference gave me a picture of a CPS connection with three straight across pins. My '91 4.0 has three pins arranged in a triangular pattern with no A-B-or C on the connector.

 

Thanks, Jerry