Crank but no start Cherokee Sport 2.4 2002... *Update: This has been solved, it was a broken Cam Belt (I won't be trusting AA diagnosis again)

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Graham C

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Hi everyone! I have pulled the rest of my hair out and have nowhere else to go! please give this a look.
It's a Jeep Cherokee Sport 2.4 Petrol manual 2002 and it's done 99,000 miles. (i've had it for about 14 years)
It's always been a bit sluggish until about 2,000 revs where it 'smooths out'
Here's what happened...
I was motoring along, and after about 12 miles it died, no coughing or sputtering, it was just like someone had pulled a plug. (I could smell petrol)
The Dash lights where still on and I was able to crank it over but it didn't fire.
I got the AA to come out to try and fix it and he came to the conclusion that it must be the fuel pump,
He squirted Brake cleaner into the intake and reckoned it coughed a bit (I'd probably do the same!)
Anyway they transported it back to my place and I started work on it.
I don't think this is relative but 2 days beforehand I had the Air-con re-charged (just thought I'd mention it)

OK, this is what I've done......
1. I changed the fuel pump (not easy) it didn't fix it; and it was at this point I checked for a SPARK and there wasn't one.
2. I renewed the CPS (Crankshaft Position Solenoid)...it didn't fix it
3. I renewed the Camshaft Solenoid...it didn't fix it
4. I checked all the fuses for continuity
5. I checked and swapped the relays and checked for power to them, the only thing I thought might be a problem was that the ASD (automatic shutdown relay) wasn't earthed, but then realized that it would be controlled by the ECU, So...
6. I sent the ECU off to Avilec Ltd and they tested it for me, and it was working perfectly. (they sent video's of spark plugs working that they had rigged up to it)
7. I took the SKIM out and went through a routine I'd read about to give the ECU a chance to think that there wasn't one, but it made no difference so I put it back, and anyway I get the impression that I wouldn't be able to Crank it if that had cut in? (not sure about that)
8. I emptied the ashtrays and cleaned the windows but I've still got no SPARK!

I checked the voltage to the coil-pack (which is a 4-in-one pack) and it's showing about 5v. so I'm thinking that would increase to 12v. when the CPS sends a signal to the ECU (I'm guessing)

I have contacted Avilec to tell me which pins are the power input pins that energize the ECU to make sure its getting power, but I think I'm clutching at straws as there is power getting to the fuel pump and I think the ECU controls that, (I'm just waiting to hear).

I just want to add to this...I have a spare cable under the bonnet which I haven't noticed before; It has a 4-way female connector at the end of it and the inside looks clean, I've searched for a loose cable that could have been attached to it but there isn't any. It's about 12" long on the drivers side and it seems to come from the bulkhead. I've checked the workshop manual and found something that matches the socket and colors and it would appear to be something called a 'Speed Control Servo' connector; I'm thinking that this is a generic loom and that my particular model doesn't have one of those (maybe it's for cruise control). When I found it I thought "This Is It!" but I've found nothing to plug into it.

I don't like being a pedestrian.
I think that's everything, I'm sorry it's a long story but I didn't want to leave anything out and waste anyone's time.
Any thought's?
kind regards
Graham
 
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KJowner

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5v is very low to drive the coil pack, I would check the supply cable.
I take it you put the other lead on the battery neutral?
 

DadOSix

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Hi everyone! I have pulled the rest of my hair out and have nowhere else to go! please give this a look.
It's a Jeep Cherokee Sport 2.4 Petrol manual 2002 and it's done 99,000 miles. (i've had it for about 14 years)
It's always been a bit sluggish until about 2,000 revs where it 'smooths out'
Here's what happened...
I was motoring along, and after about 12 miles it died, no coughing or sputtering, it was just like someone had pulled a plug. (I could smell petrol)
The Dash lights where still on and I was able to crank it over but it didn't fire.
I got the AA to come out to try and fix it and he came to the conclusion that it must be the fuel pump,
He squirted Brake cleaner into the intake and reckoned it coughed a bit (I'd probably do the same!)
Anyway they transported it back to my place and I started work on it.
I don't think this is relative but 2 days beforehand I had the Air-con re-charged (just thought I'd mention it)

OK, this is what I've done......
1. I changed the fuel pump (not easy) it didn't fix it; and it was at this point I checked for a SPARK and there wasn't one.
2. I renewed the CPS (Crankshaft Position Solenoid)...it didn't fix it
3. I renewed the Camshaft Solenoid...it didn't fix it
4. I checked all the fuses for continuity
5. I checked and swapped the relays and checked for power to them, the only thing I thought might be a problem was that the ASD (automatic shutdown relay) wasn't earthed, but then realized that it would be controlled by the ECU, So...
6. I sent the ECU off to Avilec Ltd and they tested it for me, and it was working perfectly. (they sent video's of spark plugs working that they had rigged up to it)
7. I took the SKIM out and went through a routine I'd read about to give the ECU a chance to think that there wasn't one, but it made no difference so I put it back, and anyway I get the impression that I wouldn't be able to Crank it if that had cut in? (not sure about that)
8. I emptied the ashtrays and cleaned the windows but I've still got no SPARK!

I checked the voltage to the coil-pack (which is a 4-in-one pack) and it's showing about 5v. so I'm thinking that would increase to 12v. when the CPS sends a signal to the ECU (I'm guessing)

I have contacted Avilec to tell me which pins are the power input pins that energize the ECU to make sure its getting power, but I think I'm clutching at straws as there is power getting to the fuel pump and I think the ECU controls that, (I'm just waiting to hear).

I just want to add to this...I have a spare cable under the bonnet which I haven't noticed before; It has a 4-way female connector at the end of it and the inside looks clean, I've searched for a loose cable that could have been attached to it but there isn't any. It's about 12" long on the drivers side and it seems to come from the bulkhead. I've checked the workshop manual and found something that matches the socket and colors and it would appear to be something called a 'Speed Control Servo' connector; I'm thinking that this is a generic loom and that my particular model doesn't have one of those (maybe it's for cruise control). When I found it I thought "This Is It!" but I've found nothing to plug into it.

I don't like being a pedestrian.
I think that's everything, I'm sorry it's a long story but I didn't want to leave anything out and waste anyone's time.
Any thought's?
kind regards
Graham
Graham -

Are you seeing any signal at the fuel injectors?

I’m not familiar with the 2.4, just thinking along.

Anywhere you see a 5 volt signal, it is (IMO) a reference signal for the PCM/ECM to monitor the action and report back to the computer.

How many pins on the coil pack for this beast?
 

KJowner

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Graham -

Are you seeing any signal at the fuel injectors?

I’m not familiar with the 2.4, just thinking along.

Anywhere you see a 5 volt signal, it is (IMO) a reference signal for the PCM/ECM to monitor the action and report back to the computer.

How many pins on the coil pack for this beast?
Good point!
 

jeeptorino68

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How about grounds? Check the cable at the battery. Continuity to the body/frame and to the engine block. The computer will also have a ground strap right at it. Check and clean them all
 

Graham C

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Good point!
Hi Jeeptorino68.
Thanks, I've checked all the grounds and cables for continuity to the ECU, the sensors are 3 pin and I rechecked and tested the crank sensor and the cam sensor in fact I put the old one back on because I wasn't happy with the readings on my multi-meter.
This has turned into a regular pastime every day and I've learn't a lot.
I approached this problem based on the advice and diagnosis of the AA man, instead of attacking it as I would normally.
I HAVE FOUND THE PROBLEM.... and I'm annoyed with myself for not checking what I was told i.e. "This Jeep has timing chains" ..it doesn't, and the CAM BELT HAD BROKEN.
Back in the day it would have been the first thing to check...Ah well.
Thank you to everyone who tried to help me.
I'll try to edit the title thread to show this.
kind regards
Graham (hope it hasn't ruined the engine)
 

KJowner

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That's annoying! I don't know much about the 2.4, mine are both CRDs.
 

DadOSix

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Hi Jeeptorino68.
Thanks, I've checked all the grounds and cables for continuity to the ECU, the sensors are 3 pin and I rechecked and tested the crank sensor and the cam sensor in fact I put the old one back on because I wasn't happy with the readings on my multi-meter.
This has turned into a regular pastime every day and I've learn't a lot.
I approached this problem based on the advice and diagnosis of the AA man, instead of attacking it as I would normally.
I HAVE FOUND THE PROBLEM.... and I'm annoyed with myself for not checking what I was told i.e. "This Jeep has timing chains" ..it doesn't, and the CAM BELT HAD BROKEN.
Back in the day it would have been the first thing to check...Ah well.
Thank you to everyone who tried to help me.
I'll try to edit the title thread to show this.
kind regards
Graham (hope it hasn't ruined the engine)
Good to know we are not all crazy. 3.7 have chains. Never thought of a cam belt issue.
 

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