I just cured this same sort of problem with my 2001 3.0, and it had nothing to do with coils or plugs or fuel pump. The wire loom was chafing against the steel fuel connection shroud at the top rear of the engine. It would idle rough at times, sometimes shudder unexpectedly, occasionally die, intermittently give me a CEL, and otherwise caused me to pull my hair out. I was unable to determine the cause until it constantly blew coil fuses.

Obviously, depending on how badly the wires were shorting determined the severity of the problem. Sometimes I'd go for months with no problems at all, sometimes it would miss all the time.

If you have a chaffed wire, you're just going to have to physically inspect for damage.

 

Thanks for the reply 'jagV8', think i'll admit defeat and try to drive it to a specialist as i agree i'll probably end up chasing my tail over this one.

As for the coils they are about £80 here from online specialists (more from a dealer) and looking at a few US sites they seem to be about $100. However, if anyone knows where i can get them cheaper i'd be VERY interested to hear from you.

Having looked through the JTIS (didn't realise there was a DTC summary part ) as you said the cylinder numbers are listed for OBD diagnostics. This part looks SO useful, it gets more useful every day...

I'm slowly getting to grips with the car (my previous car was only a 2.0 straight 4 and in hindsight was SO much easier to work on; but i wouldn't trade the R for the world, as Eric Banner put it you've got to 'love the beast'.)

[Going back to the original post question, a friend of mine who is a motorsport engineer had a similar problem on one of his V8 racers, turned out it was the crank sensor as he could make the motor run properly by simulating the wave pattern the sensor would produce with an oscilloscope. While i'm not a tech, more an ambitious amateur (but i do have a background in science which i think was why he was speaking to me about the wavefront characteristics {rest of the pub seemed a tad lost/disinterested}), just thought i'd pass it on if changing the coils doesn't fix the shudder - be interested if any of the experts/mechanics had come accross a similar problem/solution]

Thanks again for your help, and good luck 'florita1216' - i know the pain of intermittent running/idling and changing coils not seeming to help.

Alex

 

I wish I knew more about the coils!!! You can get all 8 for the Lincoln LS on EBay for about $240 plus shipping. I still can't find out if the Jaguar STR or regular can use them? The picture I have of the STR coils does look a good bit different so can't really recommend trying them until more information is known. Here is a STR coil below.
.
.
.

 

Great pic! Can you read the letters etc in the plastic? Might help.

 

David Manners http://www.jagspares.co.uk/Manners/C...e=10&offset=40
show the various coils at about £30-35 each, depending on engine and VIN. Still not cheap.

 

well if its for a 4.0 I have a full bank of coils with about 10K miles on them. offer me something and they are yours.


Disclaimer: I cannot promise it will solve your issue I never had any problems out of them, I just decided to change them when I did my plugs its an OCD thing.

 

Thanks for the link jagV8, but XJ coils are still £80.
(Great link though, definitely bookmarking that one for when I next need parts for the big black money sponge.)

Stupid car. (boy do I wish I had an STR right about now)

As for your generous offer Mafioso, I have an XJR so the coils look like this;

http://www.autopartswarehouse.com/im...rd/siuf347.jpg

although if your set are the same type i'll bite your hand off taking you up on the offer.

Cheers

Alex

 

Yeah but which year? You REALLY need to add your car details to your profile.

 

Though i had (pretty sure i put it at the bottom of the about me page) but i'll check and upload some pics as soon as the weather improves.

But for the record it's a 1999 XJR.

(i've seen some people on here with it written under their names in posts so i'll look into how to do this)

Many thanks for the help (don't know what i'd do without the info on here, probably have to sell a kidney)

Alex

{edit: made sure it was on my profile, added model and year to public profile message and i'll up-load some pics when i have a chance to grab some - Alex}

 

Yeah, you may have to sell that kidney

For VIN 853936-F20645 looks like a 4-pin device, probably jag part LNE1510AB

May be Standard Motor Products part UF415 but don't know if that's OE or aftermarket (I think the latter) and it still means losing a kidney

May be Airtex / Wells part 5C1180 aka C1323 but that costs even more.

Those are from rockauto.com so there'd be S/H to UK as well. Eek.

In case you missed any other online sites, mostly UK, maybe try:
www.sngbarratt.com
www.gsfcarparts.com
www.carparts-direct.co.uk
www.eurojag.com
www.britishparts.co.uk
www.jojags.co.uk
www.skjagtech.co.uk
www.scparts.co.uk
www.blackcountryjaguar.com

www.eurocarparts.com don't look to do them

 

Not the same sorry I wasnt able to assist.

 

Thanks for the links jagV8, plenty to go on (you can never have to many places to buy stuff online - LOVE the internet) but think i'm going to have to just accept this about to get expensive...
(out of interest, any one know which kidney is easiest to have removed/used the least? one careful owner [the other 2 were b**tards] and been well taken care of )

And thanks very much for checking Mafioso... but it's just sod's law isn't it. Fingers crossed you can find a good home for them (and i don't blame you for changing them, some people swear by changing them together and it can hardly hurt)

Ah well, these things were sent to try us.

At least the misfire seems to have settled down to one cylinder so i'll try changing the plug, cleaning/replacing the coil and have that injector cleaned. Not much more i can think of that could be causing the mis.

When/if i know where the culprit is i'll look into doing the other 7 to prevent it being off the road again in a month or so.

 

Well, I am still not sure what I am going to do. I had a mechanic friend run the scanner on my vehicle yesterday and no codes were stored nor did any new ones show up so I'm even more confused not. I was thinking of him replace all the coils, especially since I was able to locate a whole set of 8. They sell all 8 OEM replacements coils with the rubber boot on a plug 8 for
$ 119.00 on E-Bay. They fit many Lincolns but also 2000-2003 Jag S-Type V8. I am wondering now though, if a more sensitive scanner is needed (the one he used is the basic kind they use at auto zone) Since no error codes showed up, could it still be a coil issue? I am thinking of having him check it for vacuum leaks somewhere.

 

Dam you S-type owners with your (comparatively) cheap coils..!

Does seem odd that it's not throwing any codes as i thought the on-board diagnostics were pretty sensitive. [Tech wizard can confirm/deny]
Having spent the day taking the ignition system apart i found mine had oil in a few wells (plug boss seals gone) and the tips of some of the coils were corroded (possibly due to moisture or just age).

Cleaned it all up and she ran like a beast again... right up until the restricted performance light came on again. OBD'd it and the fault had moved with the only coil's i'd swapped so fingers crossed it's this one.

Have you taken the coils off, checked the wells and the tips (just pull the rubber boots off - i didn't realise they just pulled apart till today)?

A vacuum leak could certainly be a possibility (smoke test the intake ideally) or could it be a dirty MAF? (mine was filthy and she felt much more eager after a thorough clean, the idle was much smoother and about 150/200 RPM lower). Not sure what else to suggest.

BTW - from JTIS the COMPREHENSIVE COMPONENT MONITOR ENGINE MANAGEMENT DRIVE CYCLE

The Comprehensive Component Monitor Engine Management drive cycles are the same for V6 and V8 except for the “idle in Drive” time period. The additional “idle in Drive” time for V8 is to allow the AAI check to occur.
1 Fuel level >25%.
2 Start engine and bring to normal operating temperature >82 °C (180 °F).
3 Transmission Mode switch – Normal.
4 Switch off all heavy electrical consumers: air conditioning, heaters, etc.
5 Idle for 15 seconds.
6 Select 2nd Gear; accelerate slowly.
7 After 5 seconds, select 3rd Gear; accelerate slowly.
8 After 5 seconds, select 4th Gear; accelerate slowly.
9 After 5 seconds, select Drive; cruise at 72 km/h (45 mph) for 30 seconds.
10 Stop vehicle in a safe place. Do not turn the steering wheel after stopping.
11 Idle in Drive with foot hard on brake pedal. (Idle in Drive 30 seconds – V6; 3 minutes – V8).
12 From stop, accelerate to 80 km/h (50 mph) at 50% throttle. Cruise for 30 seconds.
13 Stop vehicle and repeat “idle in Drive”. Do not move the steering wheel.


Just wondering if this may tease out any error messages.

Good luck

Alex

 

The details of when codes set are in JTIS and are complex. To be flagged (turning on the MIL), many need to occur on 2 consecutive drive cycles and in similar circumstances. So it's possible to have faults occurring but not often enough to turn on the MIL. Proper diagnosis needs a good technician who understands this stuff properly.

You can DIY or have a non-OBD-tech do stuff but really only for the non-awkward situations. This may well be one of the awkward ones.

The conditions for CCM etc to set are also in JTIS and commonly VARY according to the car type (XJ, S, etc), model year, engine size etc. If you want to follow them (arguably not worthwhile for a non-tech), be sure to figure out the right one

Many monitors will not run if some pre-condition(s) is/are not satisfied. And then codes may not set.

(Contamination of coils is not good, btw. Consider applying some dielectric grease when cleaned up. Oil in plug wells.... think where it's from lol)

 

I had a miss on mine and it didn't throw no code up, even after the EML was flashing?

 

Please re-read what I wrote as it applies to that situation too.

In addition, flashing MIL means a catalyst-damaging misfire is occurring at that moment.

 

[quote=jagv8;218898]The details of when codes set are in JTIS and are complex. To be flagged (turning on the MIL), many need to occur on 2 consecutive drive cycles and in similar circumstances. So it's possible to have faults occurring but not often enough to turn on the MIL. Proper diagnosis needs a good technician who understands this stuff properly.
/quote]
unfortunately it happened on mine and this was being read by a very respected Independent technician on his own Jaguar reader. Replacing 2 coils rectified the miss
so I agree with what jagv8 has said in the past don't solely rely on the message centre, plus if you do get a code on your reader its only a hint at what is at fault.

 

It's good that he fixed it with not much to go on! Good techs are not easy to find.

 

Cheers for the reply.

Since i was planning on doing a full tensioner and seal job in the coming months (incl plugs and boss seals) I just cleaned everything up for now and it seems to be running smoothly for the time being (aside from having to replace another coil, but since the problem moved with the coil i know which one).

Any idea where i can get dielectric grease from here in the UK? (most people i've asked look at you like you've asked for a unicorn egg omelette)

As for the rumble on idle i'd just bite the bullet and run it in to a specialist/dealer to get a full diagnostic done. May be pricey but will probably save you money in the long run.
If you have a copy of he JTIS you could try the diagnostic procedure, or get your mechanic friend to have a go with the code reader to see if any pending faults appear (the one i pasted in earlier) and anything else it suggests.
If you don't and want any more info either I or i'm sure any other member with a copy could post any section you want/need.