Hey guys,

I'm back after a few years without a Jag, I had a X300 before that had rodknock... I bought a X308 after a long search.

The car:
1998 / 28.000km / Chains and everything else done

Because I'm just not good at buying cars it started to run rough, like my X300 did.

- It has a slow throttle response
- idle is not shaking rough, but you can feel a slight vibration in the car
- between 70km/h and 100km/h you can feel a hesitation of the car not wanting to go forward
- sometimes between that speedrange the car twitches one or two times
- when I had that case with the X300 I had a bad MAF, could this also be the case?

The car is not throwing any code, I only had a massage in the Display one time saying that the stability crontrol had an issue, but only a few seconds, not warning lights or codes.
I don't think its a big problem, the car was maintained every two years from a Jag-Dealer. I don't know if a MAF could go bad after that low millage but time also matters...

The LTFT are between 1-4% both banks are running the same, both O2's looking like they are running fine. I got MAF readings from the car but I'm not sure how much they have to be.
It does not feel like a bad ignition coil, I know it from the X300, don't know if the X308 feels like the same with a coil dying but I guess its similar.

I appriciate your help, sorry for my bad english as always

Best regards
Frederik

 

Your english is better than many who claim it as a native language. It could be a coil failing but not bad enough to cause a code. There may be oil in some of the plug holes causing a misfire due to valve cover seals leaking, worth a check. Cleaning the throttle body and butterfly plate might help, and cleaning the throttle body electrical connections also.

 

Is there a zero missing? If not, wow.

 

Hey RJ237,

thank you for your reply. Yeah that can also be the case, I think I will take a look this evening if some of them have a crack or looking bad in any way... what I can say is I already looked for oil leaks in the plug holes, because thats a common problem on the X300 also no Oil there everything dry as it should be.
I will clean the TB and maybe I can clean the MAF also with a special cleaner, I order some stuff from my part dealer to clean everything up.

I hope I can sort this out. Don't think it has anything to do with the chains or a miss timing... as I bought the car a few weeks ago it runned like a dream.

No zero missing, its a japanese import, I live in Germany and bought it from a dealer thats specialized in japanese imports. Got full service historie, sadly I can't read them. But all the invoices from the years are still there.

Thanks for the compliment, I appreciate.

 

Sounds like something minor: clean the MAF and check the plugs for cleanliness and no bent prongs; check the air filter; clean the throttle bore and plate; make sure the air hose is not leaking and tight all around (no holes); take the slack out of the throttle cable; run a good brand of fuel system cleaner though a tank; you have already checked the plugs for no oil leakage. Try it again. Maybe time for new plugs.

 

Hi,

so I checked the spark plugs, they looked good, but I changed them anyways, but nothing changed to a better or worse running. The ignition coils looking good from a visiual point, I checked for small cracks on the body, but wasnt able to find any.
Connected everything back and made sure the connectors sit good, no sign of corrosion. No oil in the holes, everything dry as it should be. I also checked the part from Airfilter to the TB, but everything is in perfect shap, no cracks nothing special I could find... I put everything back and made sure it sat proper.

Air Filter is completly new. The throttle cable I have ajusted a bit, but there wasnt much slack in it before. I have not cleaned the MAF and TB, I ordered the cleaners for them, but they didnt arrived yet. I hope the cleaning will change anything.

I'm not sure why the care isnt throwing any codes, that would help a lot to solve the problem. I will give an update when I cleaned the other parts.

Not sure if a bad chain could do such a thing or a not proper installation of this parts. But I guess from that point everything is fine, because the problem appeared over time. (I only drove it about 800-900km from when I bought it)

 

Does your code reader report Jag specific codes?

 

Hey RJ237,

I don't have a specific code reader for Jags. But it is working good with the live data, its an bluetooth adapter and I run the torque pro app on my tablet.
Also I have read codes with the same adapter from my X300 and from a friend that has a X358. Also there is no indication light for a vault, like the red or yellow bulb or a reading on the "system check" window.

So I think if there would be a code it should get it. The only code the obd is reading is the system check code from what I read should be always there.

 

There could be codes for the transmission, can bus,abs system and you would not see them with a generic reader. But since the fuel trims are excellent it's hard to suspect the fuel or ignition systems. I know it's possible to have a coil starting to fail without throwing a code, but would expect to see the fuel trim affected.
I also had a X300, great car but I was concerned about the availability of replacement parts. Now the X100/X308 are falling into that category.

 

Holding out for a dirty throttle bore and plate: shocked at how much a difference when I bought my last 308 in 2013: flat acceleration and stumbling before I bought it; cleaned it, a hot rod!! Never set any codes.

 

Yeah, that would also be my guess, but at this point I have like no experience in working deeper in that electric stuff. The Jaguar dealers I called in the near of 300km didn’t have that old diagnostic system, so that’s what they told me. I could call ZF if there is a case where a Gearbox can cause that problems... maybe this will help.

The parts are pretty much not that big of a deal but I don’t want to change 8 coils that are at 120€ a piece. You can get like everything for that car here in Germany but it has its price points.

I think the next thing is to clean the MAF and TB and see if that helps in any form. Or I have to wait until the car starts to throw a code. But I don’t want to go trough a odyssey like it was with that X300.

I will plug in the obd and make a record for the live data’s and will upload it, maybe you guys can see something that is out of the place.

Also I recognized a small knocking noise from the engine in like the first 2-3 minutes, then it goes away, but it’s pretty silent. The valves are measured at the time the chain and tensioners where changed, I have the protocol and from that point there was everything in the specifications.

thanks for everyone for the help to this point!

 

this is the link from the live datas from today driving to work.

What I recognized: the Volts of the O2 sensors goes sometimes a little crazy. Specially when I’m standing at a stop light, at the end of the video I was standing in the parking lot and let the car idle a minute, there you could feel that the car started to twitch a bit.

I hope someone has more understandings from the data’s. It’s a standard overview I use for every car, so some sensors are not supported.

I’m not sure if the car (because of Japan import) has only 2 O2 sensors (because bank 1 sensor 1 is not support and the same on bank 2, I don’t think both got dead at the same time), I have to look if there are only one on each bank at the weekend when I have a bit more time.

EDIT: checked for the O2 sensors, there are 4 of them, but I don't know why I can't read them in the Torque App... I don't belive both are broke, but I will check them at the weekend and check the connections.

 

It looks like a need a deeper diagnosis. So what would be the next procedere to work with a better software or scanner? I have sometimes read about mongose systems to diagnose the car with a old windows xp laptop...

I can get an older laptop for free, but what hardware and software do I need beside that? Is there any guide that could help me find the right software and hardware for that project? I checked the fitting of the O2 sensors before catalyticconverter and they are without any dirt or corrosion. I want to work this out, but I think I need better software.

 

I don't know for your car but a common reason why you can't read O2 sensors is that the software is somewhat broken e.g. thinks they're one kind but they are the other (e.g. linear/non-linear O2s).

I'd try other software

 

Thanks, yeah thats what I was thinking too, I have tried a few apps, dont think I will get any of it to read the upper O2 sensors. But I'm already looking for another device that could help me, but yeah I was never that deep into that specific electric diagnostic.

 

I don't see why an app won't be available if you look.

 

I tried a few apps, but hadn’t any luck getting the data from the bank 1 sensor 1 and bank 2 sensor 1. I don’t think both are dead, wouldn’t that be a thing that would throw a code.

 

Yes: P1647 and 1646 for upstream sensors; P420 and 430 for downstream. I do not think that is your problem.

 

I have a thing found with what I’m not sure with.

I changed the spark plugs one day and gave the dude in the partshop the data of my car. He gave me the following spark plugs:

Bosch fr6ki332s with a gap of 0,7mm. I was looking in a service manual and have seen that the genuine spark plugs have a gap of 0,9-1,0mm and are from NGK. Could it be possible that this is a reason for the running?
I have checked the old plugs and they where some different Bosch ones as well... technical data says they also had a 0,7mm gap.

I’m thinking about ordering the genuine spark plugs from Jaguar. I don’t know what else could cause the problems, I have cleaned the MAF and TB they weren’t very dirty but it’s done, but that didn’t made change.

Best regards

 

It's not a bad idea, but I think you will find the NGK's on ebay at a much better price.