Good Evening guys,

Have a 1997 XJ6L that belongs to a friend of mine. Its a very low mileage car, 34K on it as it sits in my garage. Its been to two shops, one being a Jag shop to no avail. Its got an intermittent hesitation or hiccup and when it hesistates, the check engine light will flash momentarily. Called Jag, verified new updated PROMS were installed. They were, i replaced them myself. Previous shop replaced crank sensor and TPS. I went and drove the car around with my Launch CRrecorder on it hoping to catch the hiccup so i can view it later on my computer. Didn't see anything other than all data dropping out. I took the PCM and TCM out to clean the connections and applied stabilant 22. I swapped the PCM relay with another relay under the hood but it still continues to hiccup. Sometimes it'll recover, twice it stalled and i had to restart which it did right away.

Not a Jag tech, do domestics, asians and diesels so i'm kinda lost to this. No codes stored in either PCM or TCM.

Thanks!

 

I had the same thing at the dealer when I worked there. X300 would hiccup, stall and ECM would go blank when running WDS Datalogger. Hours and hours later it was decided that one of the ignition coils was defective and causing the ECM to 'blank out' momentarily. Replaced the faulty coil and the engine ran fine.

I would have replaced all of them but they were something like $250.00 EACH and the customer didn't want spend that kind of money. Lately I have had good luck using the aftermarket coils sold by Motorcars and others!! They are LOTS CHEAPER!!!

Let us know what you find!!

bob gauff

 

Hi,
I am currently chasing a similar problem on my 1995 3.2L x300. I currently have the ECU out being checked for any obvious faults.
No codes being brought up on 3x different scanners. Will try replacing crank position sensor next. ( have cleaned throttle body, replaced MAFS) Has all new coils in last 18 months..Have just replaced fuel pump too!
If all else fails, it will be off to dealer to see what codes they can read!
Will post solution when I find one.

 

I have a Autologic/launch/modis/genisys and none of them catch any codes. The coils are all new within the past 12 months.

How did you determine which coil was causing the fault? I have a lab scope that i could inspect the firing pattern of the coils and they all look good.

 

What's PROMS?

 

Here is the TSB refered to (I think)

EPROM = Erasable Programmable Read Only Memory

bob gauff

 

Something else to consider are the ECM Fuelling Adaptions. The X300 was our first foray into fully adaptive fuelling. They didn't quite have the limits right and the adaptions could actually stray far enough and the thing won't even run! I have repaired many cars just by resetting the adaptions. It seems to happen especially after the car has had a running problem of some sort for some period of time. Once the repair is made the engine runs worse simply because the adaptions are so far off in an effort to compensate! Go figure. Reset the adaptions and all is well. Many times a car has been brought to me from another shop and that's all I do to fix it! [makes me look like an ACE] Attached is some reading that explains how to test and correct the fuelling; not as much for the subject matter, but because it covers the adaption reset. Trouble is, the only devices I know of that can actually reset adaptions Jaguar's PDU, WDS or some GDS 510 Scantools. Finding a dealer that has a working PDU or WDS may be a challenge.

Side note.... I've had a '95 XJR for 12 years and I have to reset those adaptions once or twice a year. I know it's time when the fuel mileage starts going to he**.

 

Thanks XJR guy,
I have reached a total brick wall with my problem.
CPU checked out fine, and yesterday spent time with my mechanic swapping throttle body, mafs, and other sensors from another car, with no change to performance.
Still cuts out at idle, and coughs and splutters if given full throttle. Has new fuel pump and filter too!
You may have just hit the nail in the head.
Off to find someone with the right tools and knowledge.
Hopefully I can report back with better news soon.
Regards,
Phil

 

While I was waiting for Jag Tech to return my phone call,
I read another post on here from Oubadah re- using Champion Spark plugs.
I had forgotten his earlier suggestion.
Short story...I just installed Champion RC9YC plugs, and problem solved.
6 weeks of head scratching gone just like that!
Try the simple fix first!
No more stalls, and cutting out engine!
Thanks Oubadah!