Hello everyone I hope your having a good day,

My 2000 XJ8 has been giving me some problems lately and nobody has an answer. I have a check engine light on and sometimes it even blinks. Not only is the light on but it occasionally restricted performance has come up. I have taken it to some places like auto zone to get the codes ran but it comes back with nothing. The car has been running rough lately but I been thinking its just because I drive it once every weekend or 2 weeks. I don't know if I'm dealing with bad spark plugs or coil overs maybe an air filter or if the timing chain tensioner is going out. The car has just 89,000 miles on it and just this July I fixed an O2 sensor problem which seemed to help until now. Any help would be much appreciated thank you

 

If you’re going to keep this car, you really should invest in a good scanner that can read live data. I know others have and with great results and a bit of time, we can do that with your car as well. I have an expensive snap on scanner so I don’t have an opinion on what you should get. Anyways this is one thing you can do that may help it run better. I’d start with removing your mass air flow sensor next to the air filter lid. It’s only 2 Phillips screws. You’ll either need some brake cleaner or air intake cleaner and spray it real good up inside that black tube of the mass air flow sensor (MAF) and that rain drop looking brown or black thing. Next you’ll need to blow it dry. Reinstall it and start it up. If it sounds better, just let it idle for about 5 minutes without any electrical loads on and without touching the gas pedal. The fuel trims may need more time to adjust. If this still hasn’t helped it out, a scanner is still recommended to buy.

 

Thanks for the tips what do you recommend to blow it out with? I don't really have anything to blow it out with but I could wipe it out. Also I know you said you don't have an opinion on a scanner but I knew a man who has owned 2 or 3 jaguars in his lifetime recommended an basic centech scanner which apparently he has had good luck with. I know there kind of cheap and I don't know if they read live feed but I was looking into buying one.

 

I do not recommend wiping out the 2 very small resistors inside that tube with anything other than what I mentioned. I would still use brake cleaner and you could use a hair dryer.

 

Normally an air-compressor with an air-gun is used to blow things clean.
I could not live without one.
But there is also a rather ridiculous product on the market: air in cans - seriously! Pressurized air in a can for that purpose...
But in your case, cleaning products and something to wipe it clean might actually suffice.

 

I completely agree with you about the compressor, Peter. I believe the compressed air in a can was for the multilevel offices and you wanted to clean out your keyboard at work.

 

CRC makes a great MAF spray cleaner; spray and let it dry. They also make a good throttle plate and bore cleaner -- I would clean those as well.

I use an Actron 9575 OBD reader, but there are lots of good choices: you need your own.

Check the battery cables to be sure they are tight; also the connectors at the false bulkhead. It sounds like an electrical issue.

You might also try a can of SeaFoam or Gamout's equivalent in a tank of gas.

 

I bought and tried to use crc maf cleaner. Used it to my xjr. Did make absolutely no any difference. After I installed a new oe maf I took the old one apart. Measure plates were completely covered with black thick and tight grime. It came off only with cleaner and scrubbing with cotton swab.

Next time I tried the maff cleaner was with my 960 Volvo. It has same type maf as aj27 has. This time it made clear difference.

So my mileage is 50/50% with maf cleaners.

 

Surprised nobody has already said it. If you don't know if the timing chain tensioners have been upgraded, then before you go any further, before you even turn the key to start the motor again, you need to find out because its like driving around with a bottle of nitrogycerin strapped to the front of the engine. Its easy enough. Remove the passenger side (US) valve cover and inspect the secondary tensioner. If the body (not the shoe) of the tensioner is brown plastic, then I recommend to remove the driver side valve cover as well and inspect them for signs of cracks or other damage. Then check valve timing. Slowly by hand, rotate the front crankshaft pulley clockwise (only, as viewed from the front of the car) until the flats on the camshafts on either bank of cylinders lines up. If you can rotate the pulley twice around and both pairs of camshafts never line up, then that bank has skipped a tooth and you could have slightly bent exhaust valves on one bank leading to your symptoms. Either way, get them upgraded right away.

If however, you find tensioners made of aluminum, then they've been upgraded and are unlikely to be your problem. At this point however, its easy to go ahead and remove your spark plugs while you have the valve covers off. You can look up spark plug fouling guides online, compare your plugs to the images and follow whatever logic is suggested in the guide.

However, it occurred to me one possibility why the auto parts stores did not retrieve any code - temperature. The ECU monitors ignition and should normally register a misfire code if a coil is bad so that's probably not it. Also if something has upset the air/fuel ratio, it would normally store at least a lean or rich code. That is unless the engine is never reaching closed loop monitoring condition, then it might not store such a code (tho I'd think it would store other codes). Could it be stuck in a warm-up mode? If you have one of those IR thermometers, you could check the temperature of the coolant at the t-stat tower. It could be that the thermostat is stuck open and its particularly cold where you are, thus preventing the engine from ever reaching the point where it will start reading the 02 sensors. I believe that will trigger a restricted performance too. Its going to run too rich as long as it thinks the coolant temperature is too cold whether it really is or whether its a figment of the ECU's imagination from a faulty sensor. If you had your own scanner, you could read the "live data" to see what temperature the ECU thinks it is and it should reach like 195 to 205F. Disclaimer, I'm not a professional mechanic.

 

"My 2000 XJ8 has been giving me some problems lately and nobody has an answer. I have a check engine light on and sometimes it even blinks".

I too would recommend an OBD checker and perhaps one with ABS monitoring. You can find a decent one for about $100.00 online but make sure it reads pre-codes. Pre-codes are OBD codes that have not been active long enough to set an OBD warning on the dash readout.
I have a Jaguar specific unit but bought an Innova scanner for less that $100 to help my grandson with is ABS problem on a Toyota. It seems to work well with the Jag too....

 

[QUOTE=pdupler;2698299]Surprised nobody has already said it. If you don't know if the timing chain tensioners have been upgraded, then before you go any further, before you even turn the key to start the motor again, you need to find out because its like driving around with a bottle of nitrogycerin strapped to the front of the engine. Its easy enough. Remove the passenger side (US) valve cover and inspect the secondary tensioner. If the body (not the shoe) of the tensioner is brown plastic, then I recommend to remove the driver side valve cover as well and inspect them for signs of cracks or other damage. Then check valve timing. Slowly by hand, rotate the front crankshaft pulley clockwise (only, as viewed from the front of the car) until the flats on the camshafts on either bank of cylinders lines up. If you can rotate the pulley twice around and both pairs of camshafts never line up, then that bank has skipped a tooth and you could have slightly bent exhaust valves on one bank leading to your symptoms. Either way, get them upgraded right away.

to be completely honest im not mechanically inclined and really don't know how to check any of those places are. Do you have any pictures or know of any videos online that shows these location? Either way thank you for the advice and I'll at least check the other things.

 

I too would recommend an OBD checker and perhaps one with ABS monitoring. You can find a decent one for about $100.00 online but make sure it reads pre-codes. Pre-codes are OBD codes that have not been active long enough to set an OBD warning on the dash readout.
I have a Jaguar specific unit but bought an Innova scanner for less that $100 to help my grandson with is ABS problem on a Toyota. It seems to work well with the Jag too

yeah I've found some decent ones but I'm also a pretty broke college kid haha but what is the jaguar specific one you have?

 

It worries me that you wrote above that you are not "not mechanically inclined", hence the following link of mine would probably only have the effect that you start ripping out your hair:

https://www.jaguarforums.com/forum/x...e-swap-266724/

But this is the complete guide to swap the timing chain, guides and tensioners, as I did it. Note that I do not have VVT, if you do, it's even more complicated.

But I am sending this link actually only for you to look at the 6th picture: This is a tricky one to overcome to get the cam covers off for you to be able to see, if you got the brown (bakelite) secondary tensioners, and if you do, then yes: The whole guide above would apply to you.

And since you are in the US: I think that all US X308 have VVT (variable valve timing). Mine is a 3.2L. You do not have 3.2L in the US. You need a special tool to hold the cam-sprockets, if you have VVT - I would normally even need it w/o VVT, but I managed without.

 

Yeah I'm not ashamed to admit that process may be over my head so to speak. I have no problems doing small things like I said earlier I changed my O2 sensor with no problems but I do know of a reputable jaguar mechanic who I'm thinking of taking it to if I can't find a problem

 

From your description, it sounds like maybe its doing this more when its under load than not? With the blinking CEL and restricted performance, etc? Make me wonder if you're using regular gas instead of premium and/or you may have a bad knock sensor or two? Also as Peter noted, your car has vvt, I'm wondering what weight of oil you're using. I don't know personally, but have read here that the VVT engines in the XJ8 can have issues with proper function if using the incorrect weight oil...again, not personal knowledge, but might be worth reading up on and crossing off the list.

The tensioners are always worth checking into if they're unknown. Even if that is not at all your problem here its a good idea to investigate them to make sure a valvetrain crash isn't in your near future.

 

Flashing MIL = misfires so bad they're damaging the cat(s).

Cats are costly so fix those misfires. Codes are a huge help if you use them.

 

it sounds like maybe its doing this more when its under load than not? With the blinking CEL and restricted performance, etc? Make me wonder if you're using regular gas instead of premium and/or you may have a bad knock sensor or two? Also as Peter noted, your car has vvt, I'm wondering what weight of oil you're using. I don't know personally, but have read here that the VVT engines in the XJ8 can have issues with proper function if using the incorrect weight oil

I only put in the 93 octane but I was going to put in some seafoam (because I have a lot I'm not using) before I fill it up again. But would it really be under that big of a load if it was just started? I live in PA and it has been pretty chilly would the cold put it under that big if a work load? The oil I have in it right now is Castrol 5W-30

 

Just out of curiosity what in your experience causes a misfire this bad? Just a really bad spark plug that's not sparking at all?

 

In addition to our suggestions above to have a look at the secondary tensioners in your Jag:
I just came to me that you actually do not need to remove both cam-covers, as looking at ONE secondary tensioner will tell you already, if you have the brown bakelite tensioners still, which should never have been used in the first place...: I pointed out before the difficulties of removing the cam cover on the side, where the oil-dip-stick is, hence, remove only the other cam cover.
This should not be too difficult, IF:
Your cam cover uses a seal, which it should, and no PO used liquid gasket instead. However, you will need a bit of liquid gasket to apply to the sharp corners, when you close it up again (and obviously a new gasket would be ideal). Also, when working on engines you'd need a torque-ratchet. You'd have to google the correct torque to put the cam cover bolts back on (my guess: 12-15Nm). The purposes of the "exercise" to remove that cam cover would be to look into the area under the front-end of the cover, if the tensioner you see there is made of brown plastic (bakelite) or if it is all metal). Metal means: Someone changed it already.

And about the misfire, which is worrying: Yes, spark plugs and coils are suspects. Those are very easy to swap on the X308. But using the correct spark plugs and coils is important.

 

If the timing is not out, probably a coil.