Project Dailying a XJR for the sake of the climate - Parts Ordered

[Guest Hooli]

Unlikely, plugs shed heat via the thread.

Cheers. I was wondering about cracked too small to see in the ceramic but if that's not how they work I'll blame something else.

[Guest Hooli]

Have a cheapo compressor? Buy a vacuum kit for about £10-15 and it’s a doddle. Pulls it through so no fannying about with tyres and caps.

 

Update read whole thread, much well played with the tensioners.

No compressor although if I ever make the garage waterproof I will get one.

[Guest Hooli]

Interestingly this morning the misfire lasted for about 100yrds, I wonder if it was just oily threads stopping the plugs earthing?

[320touring]

Top ghettospannering!

 

113/10 wuld watch agwin

[Guest Hooli]

I had the same 100yrd misfire this morning so I will investigate the plug gaps.

 

I've also booked it in for a week thurs to get the gearbox/diff/engine/supercharger oil changed and the clonk/tramlining investigated. My current thinking is the latter are both caused by worn front subframe mounts. If so, they can do them as I don't fancy that job on the drive.

[bangernomics]

Sounds like damp causing electrical tracking that disappears when warmed up. Liberal coating of wurth stuff whose name escapes me?

[Guest Hooli]

Sounds like damp causing electrical tracking that disappears when warmed up. Liberal coating of wurth stuff whose name escapes me?

 

Possible I guess, but it all looks dry inside the covers over the coils. I've not seen any multiplugs in the wiring too the coils, although there is bound to be some somewhere. If I haven't solved it in a week & ask the local specialist if there are common causes for it, I've spoke to them before & they seem quite happy to give advice.

[Guest Hooli]

Despite feeling like death warmed up this morning, due to a very sore throat so I can't breathe, I checked all the plug gaps. I meant to do it last weekend but forgot when it was all apart. It's meant to be 51thou (1.3mm to you french readers) and they varied between about 40 and 70thou, hopefully they might cure the misfire.

 

I've not tried it yet, I'm just deciding if I've got the energy to eat bacon currently.

[Isaac Hunt]

I've no experience of XJ coil,pack, but plenty of experience of oily bath plugs.

 

As you have done, a good clean and re-gap of the plugs is a good start. Then clean all the oil off the coil pack to plug connection. On late K Series, there is a spring that sits under a rubber sleeve that connects the top of the plug to the coil pack. I found one of the springs was a bit crusty/rusty at the coil pack end once. A strip and clean cured the problem which was a misfire under load.

 

Once I had cured the misfire, I shoved some new plugs in it as they were shot to pieces, gaps were huge and electrodes worn really badly, looked like they had been to the moon and back in miles. It would have been easy to conclude the shagged plugs were the cause, but no, it was the crusty coil to plug connection.

[Guest Hooli]

Cheers for the info. I did indeed wash out the ends of the coil packs last weekend and they all seem to connect to the plugs ok.

 

The odd thing is it's a misfire at low revs, as soon as it gets near 2k rpm (ie when the supercharger starts to blow) it clears up. So under heavy load it runs clean. I'll see what happens when I drive it & if it's still playing up I'll ask the specialist it's going to on thursday if they've got any suggestions.

[Guest Hooli]

Well that didn't work, I had exactly the same problem this morning. However once warm it runs better & is smoother on/off the throttle so setting the gaps has improved something at least.

 

I think I'll ask the specialist for advice when I take it in thursday, I'm already going to ask them if doing the primary chain tensioners is worth it long term (the internet seems divided on it). I suspect the answer to the tensioners is yes, which will be a bugger of a job as you need to take the bonnet off to have room to work at the front of the car. I might have* to fit a larger bottom pulley to tweak the boost up at low revs if/when I do that...

[Broadsword]

Hmm, I guess it would make sense that the coil packs are something to do with the problem since they had to be disturbed when changing the secondary timing chain tensioners. It would be convenient if you (or someone who would lend you the parts) have a set of coil packs to swap in just to verify that is the issue, but that is just a guess on my part.

 

I think if you are willing to do the full timing chain job yourself then it is definitely worth it. I would wait till there is some fine weather in the summer, buy the proper kit to lock the crank and cams and shop around for a deal on chains/tensioners and guides. It also makes the car, far, far more saleable in the future and means you don't have to worry about the engine. It was looking like the chains/tensioners on yours are pretty good so no doubt they can hang on in there for a few months. I had a look at an S-type 4.0 V8 recently. Nice colour, rust free, lots of history, lovely drive, but the timing chain was clearly clattering. Problem was the owner had sunk enough money into the thing to get hung up on getting the asking price (for now at least). Anyway by the time you hear clattering it is all a massive risk, so preventative timing chain maintenance on these sounds like a good idea.

[Guest Hooli]

Well I've still got the Sov till weds. .. but I don't have time to swap coils and see what happens.

It didn't do it when I got it, the problem started after I disturbed the RH bank to check the tensioners. So it has to be something good daft I just can't find.

The biggest issue with doing the primary tensioners is needing to remove the bonnet to get access to the front of the engine. I will do them eventually but I'm sure it's not urgent. 90% of scare stories online are the secondaries and mine where only showing the very beginning of cracks when they came out.

When I do it I can't see me resisting a bigger bottom pulley for more boost...

[Isaac Hunt]

It is allways a shame when you have to disturb items that are working just fine in order to get to another component for preventative maintenance, a bit damned if you do and damned if you don't .

 

Although if a timing chain tensioner lets go it would be a bigger damn

 

Deffo sounds like a coil pack is the place to start. Some electrical contact cleaner of the coil pack to loom connections might also be worth a try

[Ohdearme]

May not be of any help at all but on my old Alfa the butterfly valve would coke up over years so on low/no throttle the flap didn’t seal properly causing a stutter/misfire effect.

 

A shed load of carb cleaner and thumbing around the flap to clear the ridge resolved it.

 

Given what it was, the symptom obviously went away on full or more open throttle.

[Guest Hooli]

May not be of any help at all but on my old Alfa the butterfly valve would coke up over years so on low/no throttle the flap didn’t seal properly causing a stutter/misfire effect.

 

A shed load of carb cleaner and thumbing around the flap to clear the ridge resolved it.

 

Given what it was, the symptom obviously went away on full or more open throttle.

 

I cleaned the throttle body the first weekend I got it, it was manky as you describe but it's not the cause of the misfire. I had to scrape the frost off the windscreen this morning, letting it idle for the couple of mins to do that meant it run fine when I drove off, so whatever it is isn't major.

[Exiled_Tat_Gatherer]

^{OK fella - I should be taking possession of one of these fairly soon………. I've just re-read this. I'll drop it at your place for the tensioner job - OK}

[Guest Hooli]

^{OK fella - I should be taking possession of one of these fairly soon………. I've just re-read this. I'll drop it at your place for the tensioner job - OK}

 

It's a piece of piss honestly. The hardest bit was getting the dipstick tube out the way so I could lift the LH cam cover. It's meant to pull up (leave the dipstick in to guide it back afterwards) but it wouldn't so I solted the bracket to slide it off the bolt.

 

3 hours without rushing on my first go. You don't even need to put it to TDC, I did to make it easier to double check it all afterwards.

[Guest Hooli]

I've been thinking more about this and how the misfire behaves. It occasionally appears when driving and seems to be slightly more common too. It's starting to remind me of a car that's running out of fuel but it happens even with a full tank.

 

As it's not giving any codes I'm wondering if it's an early stage of what Broadsword found on his blue one.

I'll speak to the garage tomorrow when it goes in for other stuff but it seems I might be looking in the tank once I've used most of the fuel in it (shouldn't take long).

[Guest Hooli]

Well I went to drop this at the garage this morning & their daft reception wench had forgot to book me a courtesy car so I had to cancel & rearrange.

 

However talking to Chris in the workshop (I think he's the owner too) I don't need to worry about primary tensioners as they are always bloody noisey before they fail. He agrees the clunk & tramlining might be subframe bushes, but it's unusual at such a low mileage. As for the misfire he says it's classic symptoms of a MAF failure & suggested cleaning it with brake cleaner, but it'll probably need replacing.

 

Car goes in on the 12th now, so I'll try cleaning the MAF this weekend & if it doesn't work order one up. I hope cleaning it sorts it as they appear to be £192 for a replacement.

[Broadsword]

When I found those perished rubber hoses in the fuel tank of my turquoise XJR, it did get me thinking how prevalent the issue is. There is never going to be a code to point you in the direction of the problem. Fuel pump failure is mentioned a lot with these cars but I’ve never seen those hoses being mentioned anywhere. I would be tempted to bypass your secondary fuel pump to run continuously and see if that gets rid of the problem (we it would mask it). It’s a pain cutting an access port for the top of the fuel tank but it does make changing the fuel pump(S) at short notice easy if that ever befalls you.

[Guest Hooli]

I'd expect a low fuel pressure code if it was that tbh. I have thought of doing what you did with the pumps as a test, but I've not looked at the wires enough to work out how to do it yet. Depending on what the weather is like over the weekend I might investigate it as a test, like you say it'll prove it one way or the other.

[Guest Hooli]

Small update.

 

As it was still kind a daylight when I got home I popped the intake trunking off & blasted the MAF with brake cleaner. The sensor that hangs down in the airflow is now approx 1/2 the size it was and a different shape, so it was rather covered in crud. I also filled the connector with brake cleaner & sloshed it out as I didn't have any contact cleaner. I know this started when I first took that side apart to check the tensioners so it's possible it was the connector hence cleaning that too.

 

Testings will happen approx 5am tomorrow as I've got to be at work for 5:30am. Stay tuned for updates...

[Ohdearme]

This technique, although much frowned on did work wonders on my 147 as I held it to the wind and blasted it with brake cleaner.

 

I’d also add that if anyone were to order

this stuff from amazon for £2 (although it’s cheaper at Toolstation) initiating a refund for an explosive product at Amazon of this value generally results in a ‘Keep it for free Guv’ message.

 

Free cleaner ftw!!! Etc

[Guest Hooli]

I think this was running better on the way to work this morning but it's hard to tell when all but one attempt to move from a standing start triggered the traction control. It did feel even smoother than normal which has to be a good sign.

 

There was snow that half melted & refroze here last night, so although there wasn't much of it it's got ice under it. Ideal* weather to test a torquey RWD auto...

 

 

[Guest Hooli]

Smoller than smoll update.

 

Last night I also squished the driver's door seal into place where it'd pealed out at the corner. It fits into a grove in the door & just took a bit of looking at to start from the right place to sort it. No more annoying little bit of wind noise

[Guest Hooli]

Second trip to work done, it's still coughing. Not as bad but it's still not right...

 

I'll read some wiring diagrams & try forcing the second fuel pump to run all the time to rule that out. I might get that done tomorrow if I feel active.

[Guest Hooli]

I've still got the elusive & annoying misfire at times, it's also slightly erratic as to when it happens which makes it more annoying to track down.

 

Taking a leaf out of Broadsword's book I'm suspecting fuel & my car has the same twin pump arrangement his do. I've just read the wiring diagram & I know which fuse & relay is each pump, so I plan to jury rig power to the second pump to run it all the time & see if it cures the issue. As I'm starting work late tomorrow, I hope to get this done before hand.

 

If it does I've got the fun* of taking the tank out to sort the pipework, I'm not cutting an access hole as that just seems too barbaric on a decent car.

 

Oh & the driver's seat has started creaking & the back wobbling a bit on bends. So looks like I'll be checking the mountings & hinges. Bloody thing!

[Guest Hooli]

Oh one* thing I've not mentioned. Doing the plugs & cleaning the MAF hasn't fixed the issue but it has gained me about 2mpg on my commute, that's worth having as it's now up to 16.5 - 17mpg...

 

Plus it's a lot more responsive at low throttle & makes a better V8 noise which has to be a good thing.

 

 

 

 

 

 

*Two

[Guest Hooli]

Smoller than smoll update.

 

Last night I also squished the driver's door seal into place where it'd pealed out at the corner. It fits into a grove in the door & just took a bit of looking at to start from the right place to sort it. No more annoying little bit of wind noise

 

This keeps falling out again. I need to choose a sitcky stuff to put behind it to retain the seal.