Go Back  Jaguar Forums - Jaguar Enthusiasts Forum > Jaguar Models ( Modern ) > XJ XJ6 / XJR6 ( X300 )
Reload this Page >

car stumbles and revoers, transmission light on then off, Now i stalls getting worse

XJ XJ6 / XJR6 ( X300 ) 1995-1997

car stumbles and revoers, transmission light on then off, Now i stalls getting worse

 
  #1  
Old 12-20-2018, 03:21 AM
VickTrader's Avatar
Junior Member
Thread Starter
Join Date: Jun 2018
Location: Florida
Posts: 18
Received 2 Likes on 1 Post
Question car stumbles and revoers, transmission light on then off, Now i stalls getting worse

OK, So, my 97 vdp did a strange thing last week, the transmission stumbled,bucked, jerked, and then recovered to smoothness,in blink, all so fast I thought is was just one of those random events. In the next week or so it did it again only a little longer, but now concerning
Few days later in a parking lot same thing only this time it stalled dead with transmission light. I restarted, and tyranny fault light was off. I shifted the automatic like a manual, keeping it out of 4th and at higher rpm, and got home during which time It shifted very smoothly as always . Now I'm afraid to drive it. The transmission light is still off, and my ODB code reader shows no stored faults,fluid looks clean and full.
How do I trouble shoot this, it seems something is going bad, or getting dirty, or whatever. For what its worth not that i matters (but it might with a jag} my parking break has never really worked very well, now its to the point I can not pull the hand brake tight enough to keep it car from rolling. (Glad Florida is flat !} I Don't want to drive it in traffic, Has anybody got ideas how do I track down this problem?
 
  #2  
Old 12-20-2018, 03:38 AM
VickTrader's Avatar
Junior Member
Thread Starter
Join Date: Jun 2018
Location: Florida
Posts: 18
Received 2 Likes on 1 Post
Default car stumbles and recovers, transmission light on then off, Now i stalls getting worse

OK, So, my 97 vdp did a strange thing last week, the transmission stumbled,bucked, jerked, and then recovered to smoothness,in blink, all so fast I thought is was just one of those random events. In the next week or so it did it again only a little longer, but now concerning,
Few days later in a parking lot same thing, only this time it stalled dead with transmission light. I restarted, tyranny fault light was off. I shifted the automatic like a manual, keeping it out of 4th and at higher rpm, and got home during which time It shifted very smoothly as always . Now I'm afraid to drive it. The transmission light is still off, and my ODB code reader shows no stored faults,fluid looks clean and full.How do I trouble shoot this, it seems something is going bad, or getting dirty, or whatever. For what its worth not that i matters (but it might with a jag} my parking break has never really worked very well, now its to the point I can not pull the hand brake tight enough to keep it car from rolling. (Glad Florida is flat !} IDon't want to drive it in traffic,Has anybody got ideas how do I track down this problem?
 

Last edited by VickTrader; 12-20-2018 at 04:01 AM. Reason: Spelling
  #3  
Old 12-20-2018, 05:37 AM
Senior Member
Join Date: Feb 2012
Location: Manchester UK
Posts: 742
Received 520 Likes on 324 Posts
Default

I suspect you are having an engine related problem rather than transmission. The Transmission light comes on if the engine stalls so is likely a red herring.

There are many things that could cause this and if it's intermittent it will be hard to diagnose. It could be Fuel Pump or Fuel Filter (less likely as you saw issue in parking lot at low engine load). It could be bad coil(s). It could be bad CKPS. It could be faulty wiring to coils or injectors.

I don't normally suggest changing parts without proper diagnosis but a failing CKPS is almost impossible to diagnose without specialist equipment (scope) and it has so many failure modes. The CKPS will eventually fail so if it isn't the culprit right now then you haven't lost anything as you can keep it for a spare for when it does fail.

 
The following 2 users liked this post by b1mcp:
Don B (12-23-2018), VickTrader (12-26-2018)
  #4  
Old 12-20-2018, 06:21 AM
Senior Member
Join Date: Sep 2012
Location: Cambs
Posts: 300
Received 186 Likes on 122 Posts
Default

I'm going to say its a failing coil. How old are they? Are they original Jag coils? Mine will do that with a failing cheapo chinese coil, RPM will go up and down super quick like the whole car switches off for a split second, then recovers, eventually car becomes rather undriveable until coil is replaced.
Might be crankshaft position sensor too and you should have a spare in the boot at all times.
 
The following 2 users liked this post by katar83:
Don B (12-23-2018), VickTrader (12-26-2018)
  #5  
Old 12-20-2018, 08:03 AM
Veteran Member
Join Date: May 2009
Location: Yorkshire, England
Posts: 23,263
Received 3,429 Likes on 3,037 Posts
Default

+1 probably engine

Might be an air leak - check fuel trims using OBD. Very cheap and easy to do.
 
The following users liked this post:
VickTrader (12-26-2018)
  #6  
Old 12-20-2018, 07:43 PM
Lady Penelope's Avatar
Veteran Member
Join Date: Apr 2017
Location: Kansas City USA
Posts: 3,775
Received 1,213 Likes on 965 Posts
Default

A direct relationship between the engine and transmission acting up near idle to gear shift range is the communication link between the engine ECU and the Transmission ECU and is caused by a dirty connector on the transmission body signaling the transmission ECU . The end result is the engine doesn't know what to do and goes just nuts

The connector is on the left side aft , no jacking required

Never got mine off but it may be a bayonet connector that disconnects like a air hose , so don;t try too hard twisting it apart


 

Last edited by Lady Penelope; 12-20-2018 at 07:52 PM.
The following users liked this post:
VickTrader (12-26-2018)
  #7  
Old 12-21-2018, 01:45 AM
SleekJag12's Avatar
Veteran Member
Join Date: Dec 2012
Location: Scottsdale, Arizona, USA
Posts: 1,096
Received 318 Likes on 248 Posts
Default

You've owned the car for a while so you should know when the spark plugs were last changed. Has it been more than 20,000 miles? If so, it is definitely time for a new set. Old spark plugs in this engine can cause stalling and stumbling exactly like you describe. It happens at random, and gradually becomes more frequent. It is nearly impossible to actually diagnose "bad spark plugs" for an intermittent stall, so just replace the plugs if it is time. It's easy and cheap. Champion RC12YC.

That same intermittent stall was showing up again on my son's 96 XJ6 a few months ago. We replaced the plugs - problem solved!! Those Champions had about 18,000 miles on them. The old plugs looked fine and the gap was not much larger than spec, but they were worn out. Maybe it has something to do with the old original coils needing a "sharper" plug to provide adequate spark energy. Anyway, I'm happy to replace the plugs once in a while, rather than messing with the coils.

As Brendan suggests, definitely get a new Crankshaft Position Sensor (CKPS). That is also a major cause of stalling and strange behaviour that is difficult to diagnose.
 
The following 2 users liked this post by SleekJag12:
Don B (12-23-2018), VickTrader (12-26-2018)
  #8  
Old 12-27-2018, 12:03 AM
VickTrader's Avatar
Junior Member
Thread Starter
Join Date: Jun 2018
Location: Florida
Posts: 18
Received 2 Likes on 1 Post
Default

Ok, WOW, all these great suggestions.

When I first got this 97 VDP, I never owned a Jag before, so I had a Jag mechanic go over it. He replaced all coils and plugs (not with RC12YC either turns out) and kinda pricey too. Then 8-12 months later one coil bad, then another coil would go bad, so I learned how buy and replace those, and always keep 2 coil packs and tools in trunk, one time had to do quick roadside change when it did that exact thing noted “RPM up and down super quick like whole car switches off for split second, then recovers”. So; (1.) will replace plugs, Champion RC12YC, (2.) replace all coils, (3.) order a new (CKPS) Crankshaft Position Sensor (and go to YouTube school to see how to replace it), (4.) Check for an air leak – using fuel trims using OBD (5.) Check for dirty bayonet connector on the transmission body, and (6.) I won’t rule out Fuel Pump or Fuel Filter as they seem to appear in a lot of posts for all sorts of things.
Thanks to you all [SleekJag12], [b1mcp], [JagV8], [JagV8], [katar83], [Lady P.]
 
  #9  
Old 01-01-2019, 04:00 PM
Senior Member
Join Date: Dec 2010
Location: Martin, TN
Posts: 103
Received 39 Likes on 22 Posts
Default

Ok... Yes. I agree with coils... Also with the transmission plug. I've had the identical problem with my 97.
The electrical system is VERY persnickity. If one thing happens it reflects the problem all over the place.
COILS:
If you have a coil going bad you'll spark through to your magnesium valve cover and it will eventually be destroyed. Do not delay. change the coil.
If you get good coils (NOT FROM EBAY) they are expensive. But the good coils last for 100K miles or so. If you get cheap or bad ones good luck getting 10k out of them. Be careful... They will sell you cheap bad coils for high price to fool you on ebay. Go yo Welsh or Jagbits. Real lucas coils if you can find them or the Japan made ones are they only good ones. There are several threads on coils here. Typically they will make the entire dash flash but they can cause all kinds of crazy problems. When you replace the coils do the following: Make sure the coil wells are clean, not burned, re-painted and smooth. Otherwise the walls of the valve cover will be too close to the coil causing sparking, pitting and oil leaks when they burn through. Make sure you put dielectric grease on the contact/plug and the inside of the coil springs and contacts (requires taking off the rubber boot (be careful they tear)) Make sure you have a really good gap/plug and great contact. Even a slight bad connection can cause problems and wear out the coil quicker. I also add a few layers of KAPON tape around the coil to prevent sparking. It's what they use inside transformers.

Transmission: clean the connector with contact cleaner and dielectric grease before putting it back on or it will do it again. This was my first fix... only lasted about a month then: ..... it came back....

This time, it was Battery/charging system. If your charging system is weak or the battery is old or the ground is bad at the body then many weird things can start happening including transmission lights. For instance. I had an idle problem that caused the car to start slowing to about 600rpm. That caused the alternator to only put out 11 volts... bam transmission hickup and car dies. Sometimes it's difficult to start again but sometimes it starts right up and all is well... After I fixed the idle problem about a week later It started again... very very frustrating... thought I had it but no.... wow then found a slightly loose belt for the alternator.... slipping belt causing same problem... tightened belt... went away for a while... came back.... bad voltage regulator... probably from pulling too many amps when slipping... Replaced alternator. tightened belt, fixed idle... all well for a while... back to tranny lights etc in about a month. Weak battery. Replaced battery with larger version. (more amp hours)... no more tranny problems for about a year now.

I actually think it was multiple problems mixed up at the same time... Took about 6 months to get to the bottom of it all.

Other suggestions are good as well. Have solved a multitude of small issues on my 96... ckps, air leaks, MAF dirty, Fuelpressure regulator, EGR valve. Keeping an old car running after 150k is always fun

I have 3 of them and looking for another nothing drives like a Jaguar!!!
 
The following 3 users liked this post by Steve274:
Lady Penelope (01-01-2019), Scotlad (01-02-2019), VickTrader (01-02-2019)
  #10  
Old 01-02-2019, 08:36 AM
annamiata's Avatar
Senior Member
Join Date: Apr 2014
Location: nashville
Posts: 311
Received 74 Likes on 54 Posts
Default

How many mile accumulated of your Jaguar? What is full and clean mean? Is the transmission oil still has a red color? Oil pan/filter and new oil should be change out on these ZF4 transmission as a maintenance procedure. Oil pan and oil is super cheap now a day. Its a half a day job for DIY.
 
The following users liked this post:
VickTrader (01-02-2019)
  #11  
Old 01-02-2019, 10:51 AM
VickTrader's Avatar
Junior Member
Thread Starter
Join Date: Jun 2018
Location: Florida
Posts: 18
Received 2 Likes on 1 Post
Default

Oil is red color, no burnt smell, and is at or a little above the hot mark at warm idle in park. Never the less, won't hurt to change Oil pan/filter out. SO, what is proper trans fluid if I want to change it? I'm guessing it was LUCAS trans oil from factory, is there a US alternative like Dexron III or something?
 
  #12  
Old 01-02-2019, 11:10 AM
VickTrader's Avatar
Junior Member
Thread Starter
Join Date: Jun 2018
Location: Florida
Posts: 18
Received 2 Likes on 1 Post
Default

Thanks Steve for that extra follow up. Now I will be so much less frustrated when facing repeated recurrences, I know now to expect them, and, have an ever growing road map of various causes and how to fix. So, I'm feeling much better about this car, my wife loves it, she's not a car person, but when she saw that white VDP for sale, she really fell for it, its her daily driver, and we have driven all aver the country in it in the past 7 years. Joy to drive, and strangers still give her compliments on the car and ask about it ! That's my motivation to keep it going !!
 
  #13  
Old 01-02-2019, 12:51 PM
Senior Member
Join Date: Feb 2012
Location: Manchester UK
Posts: 742
Received 520 Likes on 324 Posts
Default

Yes the Transmission Fluid is Dexron III. There is some very useful information from @Don B and others in this thread

https://www.jaguarforums.com/forum/x...-fluid-177345/


But Transmission Fluid will not be a factor in to your current stall issue.

 
The following users liked this post:
VickTrader (01-03-2019)
  #14  
Old 01-02-2019, 02:46 PM
Senior Member
Join Date: Dec 2010
Location: Memphis, TN
Posts: 207
Received 30 Likes on 28 Posts
Default

As mentioned earlier in this thread and I've read elsewhere that fuel filter and / or fuel pressure regulator can be a factor contributing to a launch "stumble" . Replacing these has helped me in the past.
 
The following users liked this post:
VickTrader (01-03-2019)
  #15  
Old 01-02-2019, 07:50 PM
Lady Penelope's Avatar
Veteran Member
Join Date: Apr 2017
Location: Kansas City USA
Posts: 3,775
Received 1,213 Likes on 965 Posts
Default

There is a ground often mentioned that is missed as the large engine block strap from the lower starter mounting bolt to car frame

Hard to get a ratchet on it from the top but easy from the bottom

13 mm on the starter bolt and 8 or 10 mm on the car frame bolt

The surface on the car frame needs to be cleaned and rust free and some light bulb grease applied

The rest of the grounds in the engine bay also have to be cleaned for the engine regulation devices to work properly

I personally see the grounds as a regular scheduled maintenance item like a fuel filter

There is a vacuum line on the fuel pressure regulator going to the intake manifold

As an air leak at the intake manifold can cause the engine regulation to be out of trim and not able to correct itself in the lower RPM ranges

The FPR vacuum line makes the fuel pressure incress around !0 % ( 4 psi ) in the higher RPMs

Thee is one vacuum line under the manifold that goes to the EVAP system and is a thing that can go into detail to address that

Another vacuum line comes from the top ( # 3 cylinder ) with a tricky sealing fitting to the brake boost diaphragm which can leak itself
 

Last edited by Lady Penelope; 01-02-2019 at 08:03 PM.
The following users liked this post:
VickTrader (01-03-2019)
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Andreas Schmieg
XJS ( X27 )
6
11-12-2017 07:29 AM
mcm97
XJ XJ8 / XJR ( X308 )
12
09-22-2014 09:08 PM
raugajrjx
XJ XJ8 / XJR ( X308 )
5
02-08-2012 11:49 AM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Thread Tools
Search this Thread
Quick Reply: car stumbles and revoers, transmission light on then off, Now i stalls getting worse


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: