96BLKCHER

Hello everyone, my name is Thor, this is my first time posting in the forum.

I have a 96 jeep cherokee inline-6 4.0 automatic, Which has been sitting for about a year. During that year I made good attempt to go out and start her up and move her around some. Last month I replaced the radiator myself and drove it out into the drive way to replace all the brakes. Alas the next morning she wouldn't start. Put key in, turn over, engine sounds fine but no combustion just sits and turns over. I tried priming the carburetor with starter fluid but im not getting spark to it. So I replaced the distrib cap, spark plugs, and checked the wires from distrib to spark plugs but it still wouldn't fire

I was lost untill I read about the "Key trick," I did that and the check engine light spit out 3, 5, 5. I looked it up on a website somewhere and it said the code was for a #5 coil problem. I pulled out my Haynes manual to help me remove the coil but its almost worthless.

My question is what do I need to remove to get at the coil? Or is there a walk through somewhere that is more detailed then my Haynes manual which just says "remove the coil."

I am not the most experienced when it comes to car repair but I would really love to be able to fix her myself.

tjwalker

The 5 and 5 are simply a 55, which means "end of message" which is normal; you'll get that every time. Try the key test again and see if you have anything to go along with that 3. But don't be overly concerned about codes here.

No spark could be the ignition coil or a few other things, but a very common cause is a faulty crankshaft position sensor. That sensor is the #1 cause of no spark on the 4.0 engine.

They can be tested, but testing is not always conclusive. If you buy one, buy it directly from Jeep for the best reliability and longevity. SEARCH for lots of light reading on this very important sensor. Without the input signal from this sensor, you will not have spark and you will not have fuel going TO the fuel injectors.

The ignition coil can be tested pretty easily. Your Haynes manual will tell you how to test your coil. You will need a multimeter (buy one if you don't already have one and plan on doing any maintenance on your XJ) and the ability to use that meter to test resistance.

Good luck and keep us updated!

96BLKCHER

TjWalker thank you for you insight. After another exploration underneath the jeep I realized to get the coil off I just needed to unscrew the bracket it was attached to. I got the coil off and put it to a multimeter, first at 200ohm, and again at 200k ohm. 200 gave no reading and 200k came in at 11.9-12.0: Does that mean the primary resistance is shot?

Thanks again for the info on the sensor, ill be researching and checking that next before I get anymore parts.

If I recall correctly last week the key test gave me a 3, 4, 5 or 3, 4, 5, 5.

I love my Jeep but this hectic run around shes been giving me, I have been letting test my serenity.

Will keep posted thanks

Radi

12,000 ohms is right in the ballpark for the coil secondary. The primary (12V circuit) should read about 1 ohm.

96BLKCHER

Will setting the multimeter for 200ohm check the primary? or did I use the wrong setting

Radi

That's the lowest setting available, so you'll have to use it. May not be terribly accurate though, depending on the resolution of your meter.

96BLKCHER

Ty Rad, ill be taking it into autozone today and having it checked to be sure.

96BLKCHER

So I just got back from the zone. Apparently the underling who works there (who wasn't there today) had miss-informed me. They do not check coils there. To be specific they can only check the coil like I did with a multimeter for prim/second resistance. They guy said that they cannot check to make sure the actual coil is building a charge or not and that to do so the coil has to in reattached and use some 100+ dollar "linemen s" tool *shrugs shoulders

I recall seeing youtube videos of people checking to make sure the coil was producing a spark

I got a location/test print out while I was there for the CKP. I states in step 3 w/ ignition ON and engine OFF, backprobe with high impedance voltmeter between the sensor connector middle terminal and ether of the ends terms.

What does backprode mean?

freegdr

ok all codes will be two numbers by what you posted i get 3,4-34 5,5-55 you need to check again

freegdr

most common no spark is cps crankshaft position sensor.

Solomon7

34 I think is TPS.

Here's a list I found.
http://www.jeepforum.com/wiki/index....k_Engine_Codes

Radi

The high voltage winding of your coil measures correctly and the 12 volt primary side rarely fails...so I'd move on.

Backprobe just means to measure from the backside of the connector (stick a paper clip, small pin, etc into the connector alongside the wire) instead of opening the connector and probing the pins or piercing the wires.

FYI, checking the CPS with a multimeter isn't definitive, it is only a partial check. Just because the meter says it's OK doesn't mean it really is.

Did you happen to check for +12v at the coil primary connector with the ignition on?

96BLKCHER

Well I just finished a series of replacements.

1st: Removed and replaced old CKS with new one
a) turn key, same problem, engine turns over no start up

2nd: Removed and replaced old coil with new one
a) turn key, same problem still, no start up

3rd: Tried a small hit and starter fluid, no change.

4th: Removed and replaced old leads going to battery with new ones (in case there was a short in them, they were showing signs of cracks in them)
No change still

5th: threw a 50amp starter charge to the leads to see if it just needed a little extra juice, nope nothing

Well I am completely stumped now. I need a mechanic to look at her.

I may be defeated, but I want to thank you all for your advice and prompt responses. Will post a rockin pick from my mining trip when I get back after she up and running again.

tjwalker

Have you tried swapping the ASD relay in the power distribution center with another relay? They are of the same part number, so swapping is not an issue and only takes a minute. If ASD circuit is working properly, the ignition switch itself (in column) is still in play and although rare, the computer.

Keep us posted.
-------------------------------------------------------------------------

Spark: 12 volts from ignition switch to the ASD relay; when the key is first turned on the PCM provides a ground to the ASD relay to energize it, then the ASD relay passes 12 volts to the coil primary side. If no crank sensor signal is generated after a couple of seconds the PCM cuts the ground to the ASD relay (and fuel pump relay too) and that cuts power to the coil (and fuel pump). Key to START and once again the PCM energizes the ASD relay. Now, a critical element is the crank sensor--no signal from the crank sensor and the PCM won't trigger the coil to provide spark.

Radi

Did you check to see if you have +12V to the coil primary?