[96XJSport]

Basics: 96 XJ, 4.0, AX-15, 181k miles, bone stock.

I APOLOGIZE IN ADVANCE FOR LENGTH OF POST! But I did want to be thorough and include test results…I have searched and done my testing! ALSO, to anyone who can help, thanks in advance and I PROMISE to follow up with what resolves the problem!




Hard starting issue - only during heat-soak period of maybe 5-45 minutes AFTER hot shutdown. An IMMEDIATE restart is not an issue. Only when the engine has had time to "soak" after a nice hot drive do I have the issue. On cold starts, the engine cranks right over. It seems to me I am having vapor-lock type issues. When I have the hard start condition, the fuel coming out of the fuel rail test port is bubbling and under high pressure. I have thoroughly checked the area around each injector and have found no fuel leaks whatsoever, even when wiggling each injector and running the engine at 3k+ rpms.

It seems this issue has slowly gotten worse. I don’t recall having this issue last summer. I was having funny fuel delivery problems several months ago which appeared to be vapor-lock. I tracked down a hot run condition (temp would easily climb to 220-230 in a lot of idling or wheeling) to the fan clutch, which was shot! Now it roars, literally, and I thought my fuel delivery issues were solved.

Brand new fuel cap. Nearly new fuel filter, within 1k miles. (OLD WAS NASTY!!) Air filter fine. No CEL or codes.

Engine runs very strong and climbs smoothly. Never really idled like a Lexus, but not much different than any older domestic. With 181k miles, I don’t expect a brand new car.

As far as symptoms, sometimes it is a long start with a roughness for a couple of seconds after finally starting. One good push of the throttle clears it right up and it runs normally...Cool fuel now flowing??

Sometimes, it won't start at all on its own. Then I need to shoot some starter fluid in the intake, open the throttle, and crank. It will eventually turn over with the roughness then clear right up. Cool fuel now flowing??

It does start with a bit of richness out of the exhaust when I experience the longer starts, even without starter fluid.

Fuel pressure gauge shows rapid fluctuation during all running conditions (idle, part, or full throttle) of 48-52 consistently at any temperature. Now, I have read many different things about the proper numbers. 48-52 with a rapid flopping of the needle sounds normal. I have heard different things about the leak-down pressure. HERE I read lower than 30 psi within 5 minutes and HERE I read 24 in 5. I tend to believe the 24, since it specifically states my 96 model year and the 30 seems to be people referring to the 97-01s. QUESTION: Does the leak-test have to be performed immediately after turning off the motor OR can the leak-test be done at anytime, as long as you place the key in the run position and begin the 5 minute countdown?

I performed the test several times. Each time, immediately after shutdown, I have 47 psi. Over the 5 minutes, it never drops below 44, and sometimes climbs back up to 47 or 48. Even though I just shut down a motor that was running at 195-205 (dash gauge, no IR, sorry!), the fuel rail wasn’t too hot.

Here’s where the problem is: I allow the engine to heat soak and check the pressure between 5-45 minutes after shut down. I turn the key on and pressure always comes right up to 44-46 psi. I start the clock watch. The pressure drops VERY fast!!

Approx 10-15 minutes after nice hot shut down…Hood was left open too!


TIME (minutes)- PSI


START- 44-46
.30- 42
1:00- 39
1:30- 36
2:00- 33.5
2:30- 30
3:00- 27
3:30- 23
4:00- 22
4:30- 19
5:00- 19


Approx 20-25 minutes after hot shut down…left hood closed…


TIME (minutes)- PSI


START- 44-46
.30- 36
1:00- 29
1:30- 25
2:00- 22
2:30- 21
3:00- 20
3:30- 18.5
4:00- 17
4:30- 15
5:00- 11


So, assuming I am testing it properly (okay to test even if engine wasn’t just running) I am WAY below both the 30 psi and the 24 psi. I think the fuel in the rail is still nice and cool immediately after shutdown, hence the nice strong pressure the first 5 minutes after shut down.

Out of the possibilities available, I think I can rule out a lot. New fuel cap – tried 2 different brands just to be sure! Don't think it's an air issue...I have tried opening the throttle up for 10 seconds before starting to let air fill before cranking...doesn't help. Fuel pump seems to be very consistent and putting out adequate pressure. Check valve/pressure regulator assembly is in the tank, correct? If so, that rules that out as the problem is directly related to heat soak. Not sure if any of the sensors could cause something like this...IAC, TPS, MAP, O2, etc., but from my little knowledge on those sensors, I'm thinking no. So, because of the leak down, the only thing this leaves me with is a leaky injector, right? I have read stories of an injector leaking into a cylinder and flooding a cylinder, causing a leak down condition. Could this only happen when hot? Maybe a seal inside of the injector? This could also explain rich exhaust…

Maybe my period of "overheating" further rotted aging injectors or their seals?

Love to hear what you guys think….If you made it this far, thanks again for reading it all!

[96XJSport]

I realize no one has any ideas here, but if anyone is interested, there is a thread on another forum which has gone through a bunch of troubleshooting...take a look. And if anyone has any ideas, please post them!

http://www.jeepforum.com/forum/showthread....778#post5049778

[Jerry Bransford]

If your '96 XJ has the same type of anti-drainback valve located inside the fuel pressure regulator located atop the fuel pump assembly as is in my '97 TJ, I would suspect that anti-drainback valve is leaking and nothing more. That your fuel pressure drops after only 5 minutes gives me more reason to believe that.

When the anti-drainback valve leaks, and they are notorious for leaking in '97 and newer TJs, they allow the fuel that is supposed to be kept pressurized in the fuel rail that feeds the fuel injectors to instead drain back down into the tank. The resulting long start time afterwards is nothing more than the time it takes the fuel to get pumped back up to the fuel rail.

[SuperDave1984]

Since my XJ had a similar problem that went away after replacing pretty much everything in the fuel system, I would agree with Jerry. The fuel pressure regulator is most likely your culprit.

[96XJSport]

Jerry Bransford, on Apr 7 2008, 12:41 PM, said:

If your '96 XJ has the same type of anti-drainback valve located inside the fuel pressure regulator located atop the fuel pump assembly as is in my '97 TJ, I would suspect that anti-drainback valve is leaking and nothing more. That your fuel pressure drops after only 5 minutes gives me more reason to believe that.

When the anti-drainback valve leaks, and they are notorious for leaking in '97 and newer TJs, they allow the fuel that is supposed to be kept pressurized in the fuel rail that feeds the fuel injectors to instead drain back down into the tank. The resulting long start time afterwards is nothing more than the time it takes the fuel to get pumped back up to the fuel rail.

I don't know about that...if you check my pressures, I hold well above 24 for 5 mins after shut down. Only in the heat soak condition am I not holding. I haven't ruled out 1 or more leaking injectors though, also...

superdave1984, on Apr 7 2008, 01:28 PM, said:

Since my XJ had a similar problem that went away after replacing pretty much everything in the fuel system, I would agree with Jerry. The fuel pressure regulator is most likely your culprit.

If you replaced everything, then how do you know it wasn't a weak fuel pump? Did you do each one individually? Just curious...I just don't want to throw money at this thing. I could spend a ton of money buying a pump, TPS, CTS, CPS, IATS, IAC, new injectors, etc....but I don't have it to spend!!

I definitely appreciate the help on this guys but I'd like you guys to check out my post over at http://www.jeepforum...ad.php?t=542096. It is almost 100 posts and 7 pages long. I have put a lot more info up there and it might steer you guys a different way. Thanks again and keep the ideas coming...

[Jerry Bransford]

96XJSport, on Apr 7 2008, 03:15 PM, said:

I don't know about that...if you check my pressures, I hold well above 24 for 5 mins after shut down. Only in the heat soak condition am I not holding.

I dunno man, maybe you don't need our help afterall. But your XJ fuel rail pressure should not be at only 24 psi at 5 minutes. And if if it were only leaking into the combustion chamber via a fuel injector, how would that account for the long start. But it sounds like you already know what you need to know so good luck.

[BustedKnuckl]

First off, tip of the hat for doing such a presise fuel preasure test before hand. Looks like you've really read into the situation and know your numbers.

Just a thought outside the box - Could it be something other then fuel?

I had a strikingly similar situation with my 97 XJ. Cold start fine, after a hot run, emmediate attempt to restart would be sucsessful, but if it sat for longer then 5 minutes, it would just sit and try to turn over, but never follow through.

After a few days of narrowing down the issue, it turned out to be a fualty Ignition coil. Replaced it, haven't had an issue since.

Just thinking outside the box. Good luck!

[96XJSport]

Jerry Bransford, on Apr 7 2008, 08:37 PM, said:

I dunno man, maybe you don't need our help afterall. But your XJ fuel rail pressure should not be at only 24 psi at 5 minutes. And if if it were only leaking into the combustion chamber via a fuel injector, how would that account for the long start. But it sounds like you already know what you need to know so good luck.

Not sure what you mean by this...I definitely don't know everything I need to know, or else I'd have had this thing fixed 4 days ago! Hope you aren't offended in any way...I appreciate EVERYONES help, including yours!

BustedKnuckl, on Apr 7 2008, 08:52 PM, said:

First off, tip of the hat for doing such a presise fuel preasure test before hand. Looks like you've really read into the situation and know your numbers.

Just a thought outside the box - Could it be something other then fuel?

I had a strikingly similar situation with my 97 XJ. Cold start fine, after a hot run, emmediate attempt to restart would be sucsessful, but if it sat for longer then 5 minutes, it would just sit and try to turn over, but never follow through.

After a few days of narrowing down the issue, it turned out to be a fualty Ignition coil. Replaced it, haven't had an issue since.

Just thinking outside the box. Good luck!

Thanks man! I really have to say, pressure when I fire that fuel pump up is great...Shoots to 48 psi, everytime.

Wow, sounds strikingly similar. Funny you mention the coil too b/c on the other post a couple people have just chimed in with the same thoughts! I had considered that too, since the coil is right on the side of the motor and CERTAINLY susceptible to engine heat and heat soak. Just didn't think it could be coil/spark if when I shot starter fluid/fuel I got ignition. But someone on the other thread made a good point....you can start w/ether even with bad spark....

Sure wish I had a good coil to swap it with to see...they are $100 at AZ and AAP...god only knows dealer price!!

[BustedKnuckl]

96XJSport, on Apr 7 2008, 11:31 PM, said:

Not sure what you mean by this...I definitely don't know everything I need to know, or else I'd have had this thing fixed 4 days ago! Hope you aren't offended in any way...I appreciate EVERYONES help, including yours!



Thanks man! I really have to say, pressure when I fire that fuel pump up is great...Shoots to 48 psi, everytime.

Wow, sounds strikingly similar. Funny you mention the coil too b/c on the other post a couple people have just chimed in with the same thoughts! I had considered that too, since the coil is right on the side of the motor and CERTAINLY susceptible to engine heat and heat soak. Just didn't think it could be coil/spark if when I shot starter fluid/fuel I got ignition. But someone on the other thread made a good point....you can start w/ether even with bad spark....

Sure wish I had a good coil to swap it with to see...they are $100 at AZ and AAP...god only knows dealer price!!

#$%#W$%@$%%@$#%@ How much???

Parts America - (A vendor for Advance Auto Parts)

Thats pretty much whats sitting under my hood now, but I only paid like $35 - $40.

[96XJSport]

BustedKnuckl, on Apr 7 2008, 10:46 PM, said:

#$%#W$%@$%%@$#%@ How much???

Parts America - (A vendor for Advance Auto Parts)

Thats pretty much whats sitting under my hood now, but I only paid like $35 - $40.

I'm sorry, I take that back. I must have been thinking of the MAP - that goes for $100. AAP quoted me $29.98 for a OE replacement BWD and AZ quoted me $33.99 for their "made to last - Duralast!"

I noticed you got the accel...it's only $10 or $12 more dollars! I was thinking if I do end up doing a coil, I may as well upgrade to something a little hotter with some new wires and a cap...did you notice any MPG or power gains when you upgraded?

I think I may go ahead and pull the coil off the engine and temporarily relocate it to a cooler position, then see if my problem continues. Is this possible? I haven't looked too closely yet....

[TallJeep]

96XJSport, on Apr 8 2008, 08:12 AM, said:

I think I may go ahead and pull the coil off the engine and temporarily relocate it to a cooler position, then see if my problem continues. Is this possible? I haven't looked too closely yet....

Get a new coil and mount it either on the fender or on the firewall so you can avoid having the same problem again.

[BustedKnuckl]

When I did my coil, I did the wires (needed it BAD), plugs and used a scotchbrite pad on the dizzy and rotor. Definitely noticed a much smoother idle and no hesitation to get up and go. I couldn't tell you of any gas mileage increases, my fuel guage still doesnt work (its on the list of things to do). Other then solving the starting issue, the truck definitely needed it.

[92SquareEye]

while addressing the 3 inches of water in our throttle body over the weekend (another story for a different post), it was pointed out to me that our coil had a crack in the housing. in the wranglers with the 4.0, the coil was on the block up through 92. after that, they moved it back to the firewall due to both vibration and heat. one of the MANY $200 upgrades that arnold needs is a new ignition system. the performance distributors "firepower" ignition kit is where we're gonna go eventually. if you don't want to do the whole kit, you can get just the "screamin' demon" coil for MUCH less than A-zone quoted you for the stock one. while there's many schools of thought on this, a hotter, longer spark will allow you to open the gap on the plugs a bit more and "allegedly" get better fuel burn and more efficiency.

-dave

[96XJSport]

BustedKnuckl, on Apr 8 2008, 08:05 AM, said:

When I did my coil, I did the wires (needed it BAD), plugs and used a scotchbrite pad on the dizzy and rotor. Definitely noticed a much smoother idle and no hesitation to get up and go. I couldn't tell you of any gas mileage increases, my fuel guage still doesnt work (its on the list of things to do). Other then solving the starting issue, the truck definitely needed it.

Unfortunately, I bought the XJ about a year ago and don't know when the last time the wires, cap, and rotor were done. Thinking my starting problem is not wires, cap, or rotor, but if I do coil, than I probably should do the whole setup. I definitely don't have "Japanese" style idling, but I would gladly accept any improvements!

LrdJeffson, on Apr 8 2008, 08:06 AM, said:

while addressing the 3 inches of water in our throttle body over the weekend (another story for a different post), it was pointed out to me that our coil had a crack in the housing. in the wranglers with the 4.0, the coil was on the block up through 92. after that, they moved it back to the firewall due to both vibration and heat. one of the MANY $200 upgrades that arnold needs is a new ignition system. the performance distributors "firepower" ignition kit is where we're gonna go eventually. if you don't want to do the whole kit, you can get just the "screamin' demon" coil for MUCH less than A-zone quoted you for the stock one. while there's many schools of thought on this, a hotter, longer spark will allow you to open the gap on the plugs a bit more and "allegedly" get better fuel burn and more efficiency.

-dave

Have you had any coil-related issues? I definitely think relocating the coil is a no-brainer...I need to go out and check to see if it's possible with my wires right now. I would love to narrow it down to SOMETHING....and if I move that coil, that will kind of remove the heat soak factor that may be messing with it...

I was looking at the Firepower kit last night! When I thought the coil was going to be $100, I thought "for $90, I can get the SCREAMIN' DEMON!, if not for the name alone ( ), than at least to save $10. Of course, if I did it, I would do the entire kit. Not sure how much of a difference you'd see with the coil and OE cap & wires. But, now that I realized I can get a coil for $30, I think I'll probably end up buying a coil and then having it as a backup when I can actually afford the $200 upgrade (which will probably be NEVER!! :tdown: ).

[96XJSport]

LrdJeffson, on Apr 8 2008, 08:06 AM, said:

while addressing the 3 inches of water in our throttle body over the weekend (another story for a different post), it was pointed out to me that our coil had a crack in the housing.
-dave

Went out to take a look at mine, and low and behold, I have MAJOR cracks on my coil! Have we found our suspect??

Also, my wire to the cap is only 4-6 inches...too short to relocate it to fender or firewall!

[96XJSport]

So I am almost positive I have a bad coil. I say almost positive, because I haven't replaced it yet to see if it is definitely solved. But here are some pictures of what I found this morning. Now, these pictures are after degreasing the side of the motor 3 times!!












You can clearly see the huge crack on the side, but there is also some cracking on the top, too. This was a big indicator.

Now, going off Country Boy's suggestion that a motor will still fire with ether even with a poor spark, things started coming together. LrdJefferson's mention of a crack in his coil made me take a closer look and find the above.

I drove the XJ and got it nice and hot. Let it sit for a while, then tried to fire it up. Nothing. Had a helper crank while I checked for spark...Nothing. Wow. So I reach over and grab my nice cold Aquafina bottle. I pour some on the coil. Crank it please. Bam, fires right up.

I now need to decide what to replace it with. AAP has a BWD coil for $30, which I was tempted to buy today. But they also have an Accel available for just $40. Then, of course, I can search the web for deals.

I am not in a position to spend $200 to do a real upgrade. I know Performance Distributors makes their firepower kit (and many many more companies and kits), which sound cool, but I have Autolite Pro series wires from AAP, which are lifetime warranty. So I can get a free set of those when I do the coil, clean up the cap and rotor I've got, buy some new plugs (Maybe Champ Truck or Platinum) and be done for under $50. So, I guess I need to start reasearching coils...can get by with this one for now, but who knows how long it'll be before it dies on the highway or some other unsafe place.

I would love some advice on my coil/plug purchase, but don't want this thread to become a free-for-all...I know we can get 100 people and each one just LOVES this plug or that plug. I will definitely search through the old posts on plugs and check for some coil info too.....

As a side note, I also took the opportunity to clean the intake manifold (w/Seafoam) and removed the TB and cleaned that. Both were horribly filthy, and I already notice a very slight improvement in idle and throttle response. I will follow up with a full description and report of what I did and the results in a few days.

I will definitely post a final follow-up on the results here...

A HUGE THANKS AGAIN TO EVERYONE WHO TOOK THE TIME TO RESPOND AND TRY TO HELP - YOU GUYS ROCK!!

[BustedKnuckl]

96XJSport, on Apr 8 2008, 10:08 PM, said:

YOU GUYS ROCK!!

Thats how we do!

Now fix it and hit Corbett with us this weekend!

[92SquareEye]

96XJSport, on Apr 8 2008, 09:08 PM, said:

I would love some advice on my coil/plug purchase, but don't want this thread to become a free-for-all...I know we can get 100 people and each one just LOVES this plug or that plug. I will definitely search through the old posts on plugs and check for some coil info too.....

is it just a restarting issue? many people change over to the high output coils because of power loss at high rpms. the spark can get erratic when hard on the gas and cause an issue. if you don't realize this issue, then i would replace it with a stock coil. also, i would not do a screamin' demon, flame thrower or any other high output coil without changing the wires to a thicker size and going with a new cap and rotor. i would likely replace it with a stock rated coil and move it back to the firewall. i am not sure about your particular application, but for the YJs, i can order the wire for a 93-95 and it will be at the correct length to route it back to the firewall. i personally run bosch platinum plugs purely because i have always been a big fan of all things bosch (spark plugs, power tools, security cameras, kitchen appliances, et al.)

good luck with it!

-dave

[96XJSport]

BustedKnuckl, on Apr 8 2008, 09:27 PM, said:

Thats how we do!

Now fix it and hit Corbett with us this weekend!

Yeah man! You guys definitely hit the nail on the head...a little always helps! Regarding Corbett, check your PMs....

LrdJeffson, on Apr 8 2008, 09:31 PM, said:

is it just a restarting issue? many people change over to the high output coils because of power loss at high rpms. the spark can get erratic when hard on the gas and cause an issue. if you don't realize this issue, then i would replace it with a stock coil. also, i would not do a screamin' demon, flame thrower or any other high output coil without changing the wires to a thicker size and going with a new cap and rotor. i would likely replace it with a stock rated coil and move it back to the firewall. i am not sure about your particular application, but for the YJs, i can order the wire for a 93-95 and it will be at the correct length to route it back to the firewall. i personally run bosch platinum plugs purely because i have always been a big fan of all things bosch (spark plugs, power tools, security cameras, kitchen appliances, et al.)

good luck with it!

-dave

Yep, just a restart when heat soaked issue. Definitely no power loss anywhere. I will probably end up going stock or maybe a small step up (msd?). Question: Is the wire that goes from the coil to the cap just the same as the 6 wires that go from cap to plugs? If so, I'm sure I can manage to get one to get my new coil to the firewall or fender..

[92SquareEye]

in "theory" the wires are the same. in "practice", make sure that it is a wire designed to go from the coil to the cap

-dave

[96XJSport]

Okay, so yesterday I went ahead and installed the new coil from AAP, along with some new wires. I thought the cap and rotor were replaced right before I bought the XJ (1 year ago), so I had no plans to replace them this time around. Well, let's just say they were in bad shape. I will post pictures of them soon.

So, needless to say, I ended up doing the coil, wires, cap, rotor and plugs. I ended up leaving the coil in the stock location for now. After doing the work, the XJ started fine, although I was expecting that I would get faster starting w/my nice new spark.

So I drove to AAP to return something and when I came out....NOTHING!! Crank, crank, crank!! Got someone to crank while I pulled a wire....NO SPARK!! I ended up spraying a shot of starter fluid into the TB (which fired her right up) to get it started!!

So, I really need some help now guys. What else could I be looking at. Let's remember, it's only when it's heat-soaked....runs fine any other time...



NOTE TO MOD:

Would you please edit the thread title to add:

NEW COIL = STILL NO SPARK WHEN HEAT-SOAKED!

Thank You!!

[96XJSport]

Pictures, as promised....




Cap...Look at that corrosion!





Underside - Corrosion and almost nothing left of the center contact!!








Wire - More corrosion on coil to cap wire





Coil - Hard to see it, but there were serious cracks on every side of the coil!!

[96XJSport]

Sorry guys, not sure what's up with the pictures. Links are good and working...posted them up on another forum and they work perfectly!

[TiredPete]

96XJSport, on Apr 13 2008, 11:01 AM, said:

Sorry guys, not sure what's up with the pictures. Links are good and working...posted them up on another forum and they work perfectly!

The links are too long, too many spaces in the path....

Pete

[96XJSport]

TiredPete, on Apr 13 2008, 11:15 AM, said:

The links are too long, too many spaces in the path....

Pete

Gotcha...thanks! I'll just make them links....

EDIT: Hmmm...can't edit it anymore...

[96XJSport]

Interesting info for you guys....



Borrowed a code reader and tried to pull codes...no stored codes.



So, for the heck of it, I did the "ignition on-off 3 times" thing. I got 12, 42, and 55. 12 is completely understandable...disconnected battery a lot lately. 55 is obvious. Leaves us with 42....





An open or shorted condition detected in the auto shutdown relay circuit.



An open condition detected in the ASD relay output circuit.



An open or shorted condition detected in the fuel pump relay control circuit.



An open circuit between PCM and fuel gauge sending unit.



Circuit shorted to voltage between PCM and fuel gauge sending unit.



No movement of fuel level sender detected.





I'm going to do some research but....Any thoughts???

[96XJSport]

Just an update...Problem still exists!!

Here is some new info though:

Ran Jeep this morning, got her hot, and let her sit for 20 minutes. Went out and intentionally tried to start it, no start!

Here is what I tried:

1. Unplugged and reconnected CKS (with IGN off), then cranked - No help.

2. Unplugged and reconnected CAS (with IGN off), then cranked - No help.

3. Swapped ASD relay with starter relay, then cranked - No help.

4. Held throttle open for 10 secs with IGN off, then cranked - Wanted to start, but didn't.

5. Then, I pulled codes. I got a 12, 11, 42, and 55 - In that order.


After pulling the code 3 or 4 times, just to be sure, and playing w/relays, etc., the hood had been open for about 5-7 minutes.

After pulling the codes, I cranked, and she fired up. (I'm sure the open hood for several minutes allowed some cool down time.)

Also notable: No CEL or OBDII codes to be found.

Now, I was told that getting an 11 would mean the CAS, or pickup in the distributor. Is it possible for anything else (maybe CKS) to cause my same issues or throw the same code?

I just don't want to start throwing money at perfectly good sensors....love to just narrow this thing down and CLOSE THIS THREAD!!!

[BustedKnuckl]

I'm a fan of the military theme of "Keep it simple Stupid"

Are you chasing a ghost that isnt there? aka - a bad replacement coil?

My starter went on my YJ at work last year. We had a Useless (aka Advance) Auto Parts in the same plaza. So I went and got a starter on my lunch break. Installed it - nothing. This happened 2 more times within an hour untill they sold me one that worked. Just cause its new doesnt mean its gonna be perfect.

My shop vends a brand name battery company, and I can say off the reccord, every 5 or 6th one is bad. Right off the shelf.

Just a thought.

Edit = PS - code "55" indicates the end of the list, you probably figured that out already though.

[96XJSport]

BustedKnuckl, on Apr 21 2008, 08:24 PM, said:

I'm a fan of the military theme of "Keep it simple Stupid"

Are you chasing a ghost that isnt there? aka - a bad replacement coil?

My starter went on my YJ at work last year. We had a Useless (aka Advance) Auto Parts in the same plaza. So I went and got a starter on my lunch break. Installed it - nothing. This happened 2 more times within an hour untill they sold me one that worked. Just cause its new doesnt mean its gonna be perfect.

My shop vends a brand name battery company, and I can say off the reccord, every 5 or 6th one is bad. Right off the shelf.

Just a thought.

Edit = PS - code "55" indicates the end of the list, you probably figured that out already though.

Update:

Haven't been driving the XJ much...between the axle seal and this issue, it hasn't seen much use.

I haven't had an opportunity to test voltage on either the CAS or CKS, but I dropped by the dealership today and ordered BOTH. The parts guy said I could return 1 or both if they aren't the problem. Plus, I got them for fairly close to aftermarket price...no reason to chance any more issues with an aftermarket part.

So I think my plan is to toss the CAS in it first, since it's WAY easier to get to. See if problem goes away. If not, I'll at least try to test the voltage on the CKS before going through the work to change it. I guess we'll see which one is my trouble maker...

As far as the coil, I just find it hard to believe that the new coil works fine EXCEPT during my heat soak...seems like a stretch to me, but if the CAS and CKS don't cure my symptoms, I will definitely pick up another new coil. Actually, maybe I'll call my dealership parts guy and see how much his is and bring back the aftermarket AAP one I bought...

P.S. Mind naming the battery brand??

FWIW, I have heard that for every 10 CKS's a shop replaces, they only replace 1 CAS.....


Doing research, I found this: http://www.obd-codes...opic.php?p=3931


"I'd go with the crank sensor as well at this point, had 100's of them that would test fine with a resistance reading but once they were up to temperature they would stop generating a clean enough signal to start!
Had lots of issues with aftermarket brand sensors as well so I'd recommend a Chrysler Part. Just because the sensor circuit is complete doesn't mean the pcm will recognize it. Had a truck that would quit starting as soon as it hit 195 Degree coolant temperature then when cooled off would start again. Tricking the pcm by disconnecting the coolant sensor didn't fool it either because it was exhaust temp of the manifold that was heating it up not coolant. It never genearted a code and always had the proper resistance through it when it was checked but
wiggling the connector to it when it was running would make the engine stall. Some of the 4.0 ltrs did require an updated ignition coil for problems similar to yours but I don't know what you're using for parts so I can't be sure. Like B. Cash said be sure the wiring from the coil to the distributor and the rest of the secondary ign components are of good quality as well. I've changed alot of the crank sensors here at the dealer though so if I was going to guess that be my first

good luck and keep me postted

Jeff"

[96XJSport]

Picked up the my Mopar parts today...

Threw the new CAS in this afternoon...no help. :( Same issue when heat-soaked.

Guess I'll throw the CKS in tomorrow and see what we have....