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Discussion Starter · #1 ·
The car was in storage for a while and when I started it up the engine management light was flashing and the car sounded like a diesel. My indy has done some processes of elimination, coils , sparks etc but he thinks it might have jumped a link on the timing chain when I started her up..... Anyone had a similar issue before I get him to change the timing chain with its associated costs ?
 

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Jumping a link... I'd think that's pretty hard to do unless the timing chain was stretched / tensioners had failed. On my 4.2 Jags, you generally got some notice that the tensioners were failing because, for a while, right after you started the engine, you got a nice unhealthy growl from the engine. Plus, checking for such a problem is pretty easy by popping the valve covers; you don't need to commit to replacing the chains. How many miles are on it?

I also would expect a compression test would demonstrate a possible timing problem.

I never had this problem on my 5.0 X350 / X358s, but I did have a situation similar to yours on one of my 4.2 XJs when I had a fuel injector failing. It cranked funny, and when it finally fired, it ran really, really rough.
 
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Discussion Starter · #3 ·
Jumping a link... I'd think that's pretty hard to do unless the timing chain was stretched / tensioners had failed. On my 4.2 Jags, you generally got some notice that the tensioners were failing because, for a while, right after you started the engine, you got a nice unhealthy growl from the engine. Plus, checking for such a problem is pretty easy by popping the valve covers; you don't need to commit to replacing the chains. How many miles are on it?

I also would expect a compression test would demonstrate a possible timing problem.

I never had this problem on my 5.0 X350 / X358s, but I did have a situation similar to yours on one of my 4.2 XJs when I had a fuel injector failing. It cranked funny, and when it finally fired, it ran really, really rough.
Really appreciate the feedback. I don't remember any growl but I will get him to do a compression test and check the injectors, we will see how we go. There are 110K miles on her.... Again many thanks.
 

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Oh very good point by TheVoices2. OP didn't mention how long it's been in storage, but I was just talking to my Jag mechanic yesterday about fuel and he said that he's starting to get old fuel stank in as little as 3 months these days (especially with formulations for California). The starting carb on my Mark IX sticks after it sits for a while even though it was recently rebuilt, and he's thinking old fuel may be the culprit.

If this car was laid up for a few years, I could easily imagine crappy fuel being the problem.
 
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Discussion Starter · #6 ·
I put fresh petrol in the tank prior to starting it up so I don't think that's the problem.
Thank you for the input though..(y)
 
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I’ve never heard of a 4.2 having any timing chain setup issues.
Late 4.2s have, on rare occasions, had VVT units fail. Check everything else first.
 

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Its sounds like you've already checked this but worth mentioning. I had an engine light come on and the engine sounded like a bag of spanners, I was convinced it was terminal it was that bad.

Turned out two of the spark plugs were knackered (I didnt get them back from the garage so not sure exactly what was wrong). New set of plugs and problem solved.

Interesting that when I dropped it off I was discussing it with the mechanic and I was talking about valve issues or maybe coil packs and massive misfiring. All he said was 'it will be the plugs give me a couple of hours to get some sent over be done by this afternoon'. Might be giving him too much credit as he knew those plugs had been in there for >100k miles ........
 

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Discussion Starter · #9 ·
Its sounds like you've already checked this but worth mentioning. I had an engine light come on and the engine sounded like a bag of spanners, I was convinced it was terminal it was that bad.

Turned out two of the spark plugs were knackered (I didnt get them back from the garage so not sure exactly what was wrong). New set of plugs and problem solved.

Interesting that when I dropped it off I was discussing it with the mechanic and I was talking about valve issues or maybe coil packs and massive misfiring. All he said was 'it will be the plugs give me a couple of hours to get some sent over be done by this afternoon'. Might be giving him too much credit as he knew those plugs had been in there for >100k miles ........
Thanks for the reply, apols for not getting back sooner but I was out of the country on biz. I am assuming that is the first thing my guy checked but as they say... Assumption is the mother of all f... ups, so I will phone his and just double check.... Cheers mate.
 
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Discussion Starter · #11 ·
Just to give some closure on this thread, it was indeed the timing chain...... unfortunately.
It had stretched and jumped a link, possibly on startup after I took it out of storage. Anyway, she is now purring away perfectly ( after a couple of trips back to the garage to address some issues I wasn't happy with ) while I had open wallet surgery. such is life, glad to have it back on the road.

Thanks for all the input gentlemen.
 

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Excellent news and thanks for the update.(y)
 
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Just to give some closure on this thread, it was indeed the timing chain...... unfortunately.
It had stretched and jumped a link, possibly on startup after I took it out of storage. Anyway, she is now purring away perfectly ( after a couple of trips back to the garage to address some issues I wasn't happy with ) while I had open wallet surgery. such is life, glad to have it back on the road.

Thanks for all the input gentlemen.
That's a bummer ColmO

It turned out to be the worst case scenario and a few £££ no doubt, but, at least you know and now she's all good again.

Thanks for coming back and updating, always helpful, possibly to others as well

Cheers
Jim
 

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Discussion Starter · #14 ·
That's a bummer ColmO

It turned out to be the worst case scenario and a few £££ no doubt, but, at least you know and now she's all good again.

Thanks for coming back ad updating, always helpful, possibly to others as well

Cheers
Jim
Cheers Jim....
 
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Discussion Starter · #16 ·
Problem is I have no idea what I did wrong, if anything, on the last occasion. A 'winter storage' thread might be a good addition to the forum as more and more of these cars are being put away in the bad months as they are getting on a tad.
 

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Problem is I have no idea what I did wrong, if anything, on the last occasion. A 'winter storage' thread might be a good addition to the forum as more and more of these cars are being put away in the bad months as they are getting on a tad.
I'd say you didn't do anything wrong, stuff just inexplicably fails sometimes. Put it down to rotten luck, on the plus side, you're good for another several hundred thousand miles with that new timing chain and tensioners.

Also, it could have been far worse. Glass half full and all that.
 

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There was a recent(ish) video on YT where a similar problem arose - that of the chain having jumped a tooth or two.

This was on a Maserati Quattroporte (in reality the engine was just a GM V6 in a posh frock), the problem was found to be a stretched chain that the adjusters couldn't allow for.

The diagnosis was that the engine was probably a relatively poor design that needed more regular oil changes than the recommendation as the tensioner faces were worn as well.

The timing chain tensioners were oil pressure controlled, and this may not have any specific relevance here, only one of them had a ratchet to prevent the tensioner plunger from retracting when the oil pressure was low. There is no obvious logic to that design decision apart from stinginess - I don't know if the Jaguar ones are like that.
Either way leaving the engine unstarted for a long time may result in the oil draining from the timing chain tensioner/s which could result in a very slack chain with the unfortunate outcome.

Edit: perhaps turning the engine over with the injector/fuel pump fuse removed to build up oil pressure prior to actually starting the engine may help.

Just a thought.
 

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Discussion Starter · #19 ·
There was a recent(ish) video on YT where a similar problem arose - that of the chain having jumped a tooth or two.

This was on a Maserati Quattroporte (in reality the engine was just a GM V6 in a posh frock), the problem was found to be a stretched chain that the adjusters couldn't allow for.

The diagnosis was that the engine was probably a relatively poor design that needed more regular oil changes than the recommendation as the tensioner faces were worn as well.

The timing chain tensioners were oil pressure controlled, and this may not have any specific relevance here, only one of them had a ratchet to prevent the tensioner plunger from retracting when the oil pressure was low. There is no obvious logic to that design decision apart from stinginess - I don't know if the Jaguar ones are like that.
Either way leaving the engine unstarted for a long time may result in the oil draining from the timing chain tensioner/s which could result in a very slack chain with the unfortunate outcome.

Edit: perhaps turning the engine over with the injector fuse removed to build up pressure prior to actually starting the engine may help.

Just a thought.
Very possible. I had it in storage for about 6 months at that stage. I think in future I will use one of the maintained storage facilities around the Dublin area that will turn the car over every few days... We are very limited on the number of indie jag specialists for these older models in Ireland and the few we have know they have the market well cornered.
 

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I found the YT video, or should I say videos (5) - this car turned out to be a nightmare to fix.

A YT search on ChristMaserati will find them if you want a lesson on how not to design an engine installation :)
 
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