94 cherokee won't start, help.

[gberner]

I was off-roading and something got bbqed. The engine cranks, but no spark. Is there anything that runs under the vehicle from the passenger side that could prevent the vehicle from getting spark. I AM CHECKING THE cps in a bit but I am pretty sure it is not the problem. I could smel burning wire down that side too. any suggestions would be greatly appreciated.

[Dale Aeppli]

Originally Posted by gberner

I was off-roading and something got bbqed. The engine cranks, but no spark. Is there anything that runs under the vehicle from the passenger side that could prevent the vehicle from getting spark. I AM CHECKING THE cps in a bit but I am pretty sure it is not the problem. I could smel burning wire down that side too. any suggestions would be greatly appreciated.

Check the wires at the cps, and the ones that go to the oxygen sensor. Make sure they didn't get burnt from the exhaust manifold. Dale

[gberner]

ok I checked the cps and the cam sensor, no power to them, also I am no longer getting fuel. the engine cranks fine though, HELP!

[oljeeptek]

check the underhood fuse box for burned fuses, fusible links etc. I believe the ASD relay powers up everything under the hood during cranking etc.

[gberner]

checked fusibles and relays. asd is brand new, and I got a second one to ck it.... I just don't know. oh yeah O2 sensor is fine too.

[oljeeptek]

Ok, step back a minute.
Check a couple basics first.

Is there a security light either on or flashing?

Do you hear the fuel pump kick on for 2 seconds when you turn the key on? Are you getting any fuel pressure?

Do you get the service engine light to come on key on engine off?



Take a voltmeter or test light and check for power at any injector during cranking. The asd provides power for the f/pump relay ckt, coil+, injs etc, but ONLY for 2 seconds on key up and while the engine is turning over.

Do you have 5v at the tps or map sensor?

I'd drop the ecm and check powers and grounds next to isolate a circuit.

The o2 shouldn't have any effect on startup unless the heater is shorted.

[gberner]

well I sm going to give it all a good 4 or 5 hour go through tomorrow and then I take it some where. I have gone through everything suggested here, which I greatly appreciate. I was I have a feeling that there is a short somewhere that I just have not noticed and is somehow causing a shutdown. Does this sound plausible? Any other suggestions would be wonderful as well. Thanks again

[lwh1955]

Originally Posted by gberner

I was off-roading and something got bbqed. The engine cranks, but no spark. Is there anything that runs under the vehicle from the passenger side that could prevent the vehicle from getting spark. I AM CHECKING THE cps in a bit but I am pretty sure it is not the problem. I could smel burning wire down that side too. any suggestions would be greatly appreciated.

Try checking the balist resistor. It is usually located on the drivers side of the engine compartment, on the firewall. It is white in color and looks like a block of chaulk or plastic. It should have one wire going to it and one wire comming out of it. One or two screws may be holding it. Remove the screw(s) and check the back of it. If the spring or wire on the back of it is burn in half, your car will not have any spark. This is an old chrysler design.
Good luck!

[gberner]

i have not checked the ballast resistor but I now have power to everything. and correct power too!!! So the problem is that I am getting no spark. I have power going to the coil, about 12to 13 but as I crank the engine the power voltage to the coil goes down and I have no pwer comming from the coil. I have 2 new ones and neither are producing spark. I do only have one bolt holding on the coil. does it ground through it. any more suggestions.

[lwh1955]

You could have something as simple as a bad coil or a busted timing chain. What you need to do is get a chilton's Manualfor your Jeep. Well worth the money. The first thing I would check is a secondary circuit test. (Too long to describe here). It is not hard but sounds like the problem you are having. The resistance from the coil on this test is different than the voltage you are trying to check when you are cranking the engine. Bottom line is, you need to do a secondary circuit test first and then a primary circuit test. I think you will find your problem here. If you don't do this first, you will just be chasing your tail. Lots of luck. I know how you feel, but a good manual is the way..

[Saudade]

You said earlier you had no power to some of the sensors and later said everything had power. What did you do to correct this?

When checking the sensors, did you simply measure voltage or did you follow a test procedure? The following link takes you to AutoZones's online manual with the test procedures for the sensors.

http://www.autozone.com/servlet/UiBr...3d80152389.jsp

This one is for ignition system components.

http://www.autozone.com/servlet/UiBr...3d80151c9f.jsp

[gberner]

nothing. actually it just came back durrring process of moving it around. I did however go through every piece of wire I could find checking for damage and testing for looeness. I still however do not have a spark, though there is power going to the coil which decreases durring ignition. I don't know if that is normal or not. Oh and I put several diff coils on incase one was faulty. hmmm.

[oljeeptek]

Originally Posted by gberner

nothing. actually it just came back durrring process of moving it around. I did however go through every piece of wire I could find checking for damage and testing for looeness. I still however do not have a spark, though there is power going to the coil which decreases durring ignition. I don't know if that is normal or not. Oh and I put several diff coils on incase one was faulty. hmmm.

Did you get anywhere with this yet?

How far is the coil power (feed voltage) dropping during cranking?

It should stay at battery voltage, which also shouldn't go below 10v cranking or the computer cant work right.

If you are getting power to the coil for only two seconds or so during cranking, the computer is not getting cps and/or cam sensor inputs. It will shut down power to the coil, fuel pump, injs etc.

Your coil is likely not at fault. Neither is a ballast resistor used for ignition on your jeep.

[gberner]

well, I am in the process of changing out the cps. I don't know for sure if that is the problem but My friend says it is. The power to the coil drops to about 10.5. It does not cut out after a few seconds either. There also is power to the injectors in a 2 sec burst. I have gone through just about everything electrical at this point. A guy I was talking to suggested the timing chain, but in al my previous experiences, if the chain breaks You can hear it. I don't know. I have 4 other people baffled as well, 2 of which are mechanics.