"Failsafe mode" and has a misfire
 

1999 XKR convertible.

Ho all,

My Jag is showing the error "Failsafe mode" and has a misfire but the only codes it showed were and now they have gone away.

MSDIAG/RECORD/OBD_UK_TEST_0003_ReadCodes
vmd_dtc_00004.rex
MSDIAGRECORD/OBD_UK_TEST_0003_ReadCodes
vmd_dtc_00005.rex

While it was showing the codes I ran a live misfire test with the result being:

MSDIAG/RECORD/OBD_UK_TEST_0004/I-M Readyness/SinceCodesCleared/vmd_IDS_00006.rex

I'm sure the misfire is going to be a coil or two but without codes I don't know which ones to replace and I've previously been advised not to change the all.

Any advice or help would be much appreciated.

You need to post the actual codes you got, rather than whatever those files you seem to have posted the names of.

Those are the codes the Icarsoft reader gave me, photos are below.

https://cimg2.ibsrv.net/gimg/www.jag...92e55b2874.jpg
https://cimg3.ibsrv.net/gimg/www.jag...6fd0952e6b.jpg
https://cimg4.ibsrv.net/gimg/www.jag...e777633f62.jpg
thanks

Maybe try and update the software on your icarsoft, because that is not right.

You are looking for a code like P0301 etc

The reader is brand new and has the latest software installed, ill plug it into the car again and see what its showing.

Thanks

Something's wrong with the tool or the way you're using it.

Codes will be like letter(P/B/C/U) and 4 digits. Misfires should be P codes.

Is your tool using ISO 9141 protocol? Check in setup to be sure.

Update.

I got the 1999 XKR in my local garage today (not a Jag specalist) who also couldn't get any codes from the laptop they use so they took the coil covers off to see the condition of the coils and spark plugs and all 4 on the passenger side (UK car) are full of coolant.

When I drove the car their I did get a "coolant low" warning after 20 mins.
I'm guessing its best to start with running a compression test? if so Whats a good/bad reading to get and do I need to remove the coolant before running the test?

If the head gasket has gone is it something a DIYer could takle or would I need a specalist Jag garage?

Any advice is much appreciated.

The only pipe high enough would be the bleed hose from the coolant reservoir to the thermostat tower but I'd expect that to make mess of the top of the engine

Is it definitely coolant?
Oil, via leaky boss seals, or water, via the bonnet vents, could get in there.

I'd just clean all the plug wells out for now and see if that restores order.

Thanks for the reply Michaelh.

I only know what I was told over the phone but I was told they were all full of coolant.

I'll do as you advise. I'll pump out the "coolant" dry everything as best I can and leave it exposed for 24 hours to dry out further then start it up and cross my fingers. 🤞

I've taken the coil covers off along with the coils themselves to look at the spark plugs, as you can see from the photo below a small amount of coolant does look like it's made it way in there.

https://cimg2.ibsrv.net/gimg/www.jag...0e90d9dc54.jpg

this is on the passenger side bank (UK) so I have taken the rubber off the coils and cleaned/dryed them off, the other side has about the same amout of oil in but would this make the car misfire?

I've changed the plugs too but not tried to start the car yet.

If it's only a small amount that shouldn't cause problems. Clean them out and see how you go.

I'd give the coil and cover bolts a smidgen of anti-seize on reassembly. Torque to 4Nm only.

I've changed the plugs on the drivers side bank (UK car) but when I tried to change the plugs on the passenger side bank they are all really tight to the point where I have broken the head on one plug. 😞

Does anyone have a tip for removing a broken/strpped plug?
is there a penetrating liquid I could use to losen the other 3 plugs that won't cause further problems?

My Jag doesn't seem to want to run properly.

thanks in advance.

Yuck. Just what you need. Whatever was in the plug wells has caused some corrosion.

For the three remaining, I'd part-fill the wells with a good penetrating oil and leave it to work for a few days.
Kroil gets good reports from the US members, but I haven't found a source here. Plus Gas or similar? I've read that a 50/50 mix of ATF and acetone (or diesel) also works well.

What to do with the broken one? The main thing is to ensure that nothing nasty gets into the cylinder, else it's a head-off job.

I'd certainly sparingly squirt some penetrating oil around what's left of the plug thread if possible. Heat isn't really an option I don't think, but freezer might work? I'd be dubious about any of these reverse-thread 'extraction' tools as they tend to expand whatever they're inserted into (or fracture in there making the job 10x worse).

Hopefully someone who's been there will jump in with some more suggestions.

Michael's suggestion of filling the plug wells partially full of penetrant is great advice. Use at least enough penetrant to cover the plug bases. What has happened is that galvanic corrosion has formed between the steel spark plug threads and the aluminum cylinder head threads due to the presence of an electrolyte (coolant). Here in the U.S., well-known brands of penetrant include Liquid Wrench, PB Blaster, Sea Foam Deep Creep, BG In-Force, Kroil, CRC Knock'er Loose (my personal favorite), Marvel Mystery Oil, and WD 40 Specialist Penetrant (regular WD 40 is a general-purpose water displacement product and not the best penetrant).

After allowing the penetrant to soak in overnight, what I would do is to try to rotate each plug counterclockwise just until it begins to turn. If all the penetrant has soaked down past the plug, apply some more penetrant, then turn the plug back clockwise until it just begins to tighten. Then turn it counterclockwise a little more than before, apply more penetrant, then turn the plug clockwise again. Repeat until you can turn the plug all the way out. This process helps to break the corrosion apart without forcing it and destroying the threads in the aluminum head.

And to answer one of your other questions, yes, either oil or coolant on the spark plugs can cause misfires. The threaded junction between the spark plugs and cylinder head is the ground path for spark. So when oil (an insulator) or coolant (a weak conductor) seeps down the threads of the plugs, it adds considerable resistance to the ground path of the spark circuit which can cause weak or no spark. The solution is to cure the source of the oil and coolant, then remove (and consider replacing) the spark plugs, clean the old plugs if you intend to reuse them, and clean the threads in the cylinder head. To clean the threads in the head, I use zero-residue electronic cleaner and a brass-bristle bottle brush that is a tight fit in the threaded hole.

I hope your next post is a success report!

Cheers,

Don

Thanks very much for the advice Micheal and Don I've ordered some Liquid Wrench as couldn't get CRC Knock'er Loose in the UK, when it turns up I'll do as advised and soak the 4 plugs for a few days and report back.

With regard to the broken plug its still in one peice but spinning, has anyone every removed a similarly knackered one from their car and have some tips on freeing it?

What annoying is I didn't use a massive force to snap the plug.

Broken spark plugs are common on some engines, such as Ford Tritons. There are special tool kits available, but often you just need a quality EZ-Out type extractor of the appropriate size. See this article:

https://www.championautoparts.com/Te...park-Plug.html

Search "Broken Spark Plug Removal" for lots of videos showing various scenarios and techniques.

Before you begin extraction, turn the engine so the piston in the affected cylinder is at bottom dead center, and take great care not to drop anything (like an extraction tool) into the cylinder... If I find that the extractor is creating metal dust from the spark plug base, I will use a shop vacuum to remove the dust as I go to reduce to a minimum the amount of metal particles that fall into the cylinder when the plug base comes out.

Cheers,

Don

Odd. I'd expect the plug to have sheared where the thread meets the body, in which case the latter should just pull out.

Once you've done that, you can put a bung of some sort in the top of the thread so you can part-fill the well with penetrating oil.

The link DonB has posted should help you through the rest.

I've been away through work for a couple of weeks but here is an update.

I soaked the 4 spark plugs for a couple of days before trying to remove them, the 3 intact ones were free after a bit of pressure, using a similar tool to the one above I managed to free the broken plug. Happy days.

I cleaned out as best I could where the spark plugs are located and replaced with new plugs all round, with the coil packs I cleaned and dried these along with removing the small springs and carefully cleaned the contact points.

Reattached everything but when I started it up the misfire is still happening except now the car is struggle to idle. 😓

No codes are showing either.

I'm starting to think it could be a fuel issue so after reading the post below I'm going to start with changing the fuel filter when it arrives and adding an injector cleaning, can someone recommend a good cleaners for these cars?

https://www.jaguarforums.com/forum/x...-290025/page2/

If the above fails I will start to look at the fuel pumps but I was wondering if I had missed something or if the sound file of my car running might offer a clue to someone with better ears then mine.

Thanks in advance.

Hi Phil,

Glad to receive an update from you, but sorry the engine isn't cooperating. I can't remember which bank had the broken plug, but is it possible you left something disconnected, like the Mass Air Flow Sensor (MAFS)? Or a vacuum or breather hose?

Have you ever been able to get your scan tool to read codes properly?

Regarding fuel injector cleaners, to my knowledge, the only one Jaguar has ever recommended is Wynn's. I use Chevron Techron Concentrate Plus because it is very similar chemically to Wynn's and has been tested by BMW engineers and found effective, so it is bottled with BMW labels for use at BMW dealerships, and it is more readily available in the U.S. I order it from Amazon in the 20 ounce bottles, which is what BMW recommends.

Cheers,

Don