My dual fuel ( LPG) 1999 S type runs rough under load/on hills and is getting progressively worse. This happens both in the LPG and petrol mode but reverts to petrol as soon as the engine struggles. I have then had to operate the throttle judiciously up and down to avoid the problem as much as possible.
I initially thought it was an LPG problem but as it happens in both modes I guess it could be the plugs, leads, fuel injectors or other periphial stuff causing the problem. I guess also there is an LPG fuel sensor which is having a hard time at the moment.
Has anyone had a similiar experience ( take out the LPG in the equation ) and do I need to go to a main dealer ( God forbid) to have diagnostics done, or could I use other garages?
Keith
Rough Running
Moderators:GJS-typeR, Montana5
Hello Keith,
Taking LPG out of the situation, the problems you have, do sound as if they could be electrical. That`s where most rough running starts from with V6 or V8 cars.
In my experience a good indipendant Jaguar specialist will be able to tackle an initial electronic interogation for you and be knowledgeable of all the common faults and symptoms that occur with modern Jaguars.
Tired spark plugs frequently cause problems. I have found that 5ok miles is about the limit for reliability, rather than the recommended 60k before a plug change is schedualed.
Plug on coils also fail due to age or water or oil flooding.Leaking rocker or internal seals can cause this scenario.
Hope this gives you a pointer.
Please let us all know how you get over the problem.
Kind regards,
Mike Kennedy. JEC s-type Co-ordinator
Taking LPG out of the situation, the problems you have, do sound as if they could be electrical. That`s where most rough running starts from with V6 or V8 cars.
In my experience a good indipendant Jaguar specialist will be able to tackle an initial electronic interogation for you and be knowledgeable of all the common faults and symptoms that occur with modern Jaguars.
Tired spark plugs frequently cause problems. I have found that 5ok miles is about the limit for reliability, rather than the recommended 60k before a plug change is schedualed.
Plug on coils also fail due to age or water or oil flooding.Leaking rocker or internal seals can cause this scenario.
Hope this gives you a pointer.
Please let us all know how you get over the problem.
Kind regards,
Mike Kennedy. JEC s-type Co-ordinator
Thanks Mike,
I have just had the car serviced with the plugs being replaced, a couple of these were fouled by oil.
The problem of rough running apart from idle blips has been alleviated, but I will monitor the situation because of the oil ingress as this will have to be remedied.
Your articles are extremely helpful.
Keith
I have just had the car serviced with the plugs being replaced, a couple of these were fouled by oil.
The problem of rough running apart from idle blips has been alleviated, but I will monitor the situation because of the oil ingress as this will have to be remedied.
Your articles are extremely helpful.
Keith
Get that throttle body and butterfly plate nice and clean, Keith.
Use carb cleaner, rag and a toothbrush. The throttle throat has a special coating around the butterfly plate. Go easy here and don`t damage the coating. Get the whole throat and plate spotless.
You will probably find the idle improves. The incoming charge air will have a much easier time entering the engine and the butterfly plate will move easier in its bearings.
Clear the gunge and things should improve.
Mike Kennedy. S type Forum Co-ordinator.
Use carb cleaner, rag and a toothbrush. The throttle throat has a special coating around the butterfly plate. Go easy here and don`t damage the coating. Get the whole throat and plate spotless.
You will probably find the idle improves. The incoming charge air will have a much easier time entering the engine and the butterfly plate will move easier in its bearings.
Clear the gunge and things should improve.
Mike Kennedy. S type Forum Co-ordinator.
Sounds as if there may be an airleak somewhere, Keith.
If the car is a V6, check the two small vac pipes at the rear of the engine. The top one is quite easy to replace but the lower pipe needs the inlet manifold to come off. Usually leaks here can be detected as a hissing sound.Pipes are cheap enough. Fitting can be tedious due to lack of space.
Also check the security of any trunking seals or crank case vent pipes. Have a good look round for anything else unusual. Also check tightness of inlet manifold bolts.
Leaks on the charge air side will upset smooth running. No doubt about it.
Let us all know how you fix it.
Mike
If the car is a V6, check the two small vac pipes at the rear of the engine. The top one is quite easy to replace but the lower pipe needs the inlet manifold to come off. Usually leaks here can be detected as a hissing sound.Pipes are cheap enough. Fitting can be tedious due to lack of space.
Also check the security of any trunking seals or crank case vent pipes. Have a good look round for anything else unusual. Also check tightness of inlet manifold bolts.
Leaks on the charge air side will upset smooth running. No doubt about it.
Let us all know how you fix it.
Mike
Mike,
Again thanks for your help and all the best for the NewYear.
Reference rough running, it has returned, I thought it had gone because I have used the car around town only since the cars service therefore low speeds and no apparent problems.
At higher speeds it returned, and I now think its a transmission problem and its a shudder rather than rough running when the engine changes up to higher gears. Its an auto box so I tried it in manual shift and it seemed OK in 2 and 3, however in 4 and D at about 2000 RPM it drops revs to about 1500 and struggles. Above this rev range it seems OK.
It may mean a visit to an autobox specialist, as I feel that if I went to Jaguar, their answer would be to fit a new box, which would not be viable for my 1999 car. My guess also its that the sealed for life gearbox with oil will also need lattention anyway.
I also had a look at the engine folowing your advice to find the throttle and clean it, but got lost, I know its in there somewhere. However as the temperature was well below freezing I decided on a wobbly coffee instead so its manyana maybe.
I love the comfort and style of the S Type, which to me even at 11 years old is a modern car especially compared to my 1961 MK2, however its proving a high maintenance object and a worry most of the time, ( warning lights and things telling you of impending doom ). So if it goes on I will revert to something a bit more agricultural. I hope not, but watch this space.
Keith
Again thanks for your help and all the best for the NewYear.
Reference rough running, it has returned, I thought it had gone because I have used the car around town only since the cars service therefore low speeds and no apparent problems.
At higher speeds it returned, and I now think its a transmission problem and its a shudder rather than rough running when the engine changes up to higher gears. Its an auto box so I tried it in manual shift and it seemed OK in 2 and 3, however in 4 and D at about 2000 RPM it drops revs to about 1500 and struggles. Above this rev range it seems OK.
It may mean a visit to an autobox specialist, as I feel that if I went to Jaguar, their answer would be to fit a new box, which would not be viable for my 1999 car. My guess also its that the sealed for life gearbox with oil will also need lattention anyway.
I also had a look at the engine folowing your advice to find the throttle and clean it, but got lost, I know its in there somewhere. However as the temperature was well below freezing I decided on a wobbly coffee instead so its manyana maybe.
I love the comfort and style of the S Type, which to me even at 11 years old is a modern car especially compared to my 1961 MK2, however its proving a high maintenance object and a worry most of the time, ( warning lights and things telling you of impending doom ). So if it goes on I will revert to something a bit more agricultural. I hope not, but watch this space.
Keith
Update Rough Running
I travelled to my local Jaguar dealer for a computer diagnosis which indicated misfiring on plugs 4 and 6 and recommended changing all 6 coils. This had been pointed out by Mike earlier. However I also suspected a gearbox problem and lo and behold the gearbox fault light came up for the first time on the way home. I went straight back to the dealer and " the computer said" solonoid or worse. However now I think it was brought on by the engines running problems up a steep hill. The fault light cleared after stopping and restarting the engine.
So going back to the first sentence I was quoted £356 and £438 inclusive to change the coils. As my car is only worth £2K+ my intention is to replace the defective coils only and re appraise afterwards. If somebody would give me the part number for the coils it would be appreciated (1999 3.0L )
Again, watch this space.
The diagonostic check cost £40.19.
Keith
So going back to the first sentence I was quoted £356 and £438 inclusive to change the coils. As my car is only worth £2K+ my intention is to replace the defective coils only and re appraise afterwards. If somebody would give me the part number for the coils it would be appreciated (1999 3.0L )
Again, watch this space.
The diagonostic check cost £40.19.
Keith
Try E-bay first Keith. Some good deals to be had there. I`ve seen coils advertised as new for the V6 at around £25 each. Pay peanuts for second hand units as some may not have much life left. On the other hand you may be lucky and get a good full set for £50!
Alternatively. Eurojag, Just Jags, Jo Jags, Black Country Jags etc.
A few minutes on Google and E-bay is sure to get you a result. regret, do not know part number. Go on the car VIN number and approximate date of manufacture. There is to my knowledge only one coil type for the car of that age.
As regards a transmission rebuild, I paid around £1700 for a referbished box and obligatory torque converter overhaul at Bristol transmissions. Faultless ever since.
These dealers know how to sting when it comes to the diagnosis machine. In Bristol, the guys looking after my car used to do it for free. It only takes two minutes to plug in and little longer to get the result.
Plug and coil failure has been known to kick up fault codes that have nothing to do with the true problem. One of them is to cause a gearbox fault to appear when in fact there is not a problem.
However, as your scan revealed a gearbox solenoid problem, you might need to have the box rebuilt. Mine was the same when it failed. Solenoids chock full of geartrain, brake band and other weardown particulate. Hench my rebuild.
Best advice is to have the gearbox oil changed every two years or 24k miles.
Your biggest problem is how much to spend on the car to get it going again properly. It is a dilema as you might have to spend £2K on a 2K value car. May be better to find another good one for a similar figure and keep yours for spares. Tough bullet to bite. Quick easy option and perhaps fewer tears.
Mike
Alternatively. Eurojag, Just Jags, Jo Jags, Black Country Jags etc.
A few minutes on Google and E-bay is sure to get you a result. regret, do not know part number. Go on the car VIN number and approximate date of manufacture. There is to my knowledge only one coil type for the car of that age.
As regards a transmission rebuild, I paid around £1700 for a referbished box and obligatory torque converter overhaul at Bristol transmissions. Faultless ever since.
These dealers know how to sting when it comes to the diagnosis machine. In Bristol, the guys looking after my car used to do it for free. It only takes two minutes to plug in and little longer to get the result.
Plug and coil failure has been known to kick up fault codes that have nothing to do with the true problem. One of them is to cause a gearbox fault to appear when in fact there is not a problem.
However, as your scan revealed a gearbox solenoid problem, you might need to have the box rebuilt. Mine was the same when it failed. Solenoids chock full of geartrain, brake band and other weardown particulate. Hench my rebuild.
Best advice is to have the gearbox oil changed every two years or 24k miles.
Your biggest problem is how much to spend on the car to get it going again properly. It is a dilema as you might have to spend £2K on a 2K value car. May be better to find another good one for a similar figure and keep yours for spares. Tough bullet to bite. Quick easy option and perhaps fewer tears.
Mike
Your a star Mike,
I will be taking the ebay option and will get a couple of new ones which I will get the local garage to fit. If that works, great. If not, I may get the LPG conversion transferred to my Mk2 and sell the S type to cover the cost. But I hope not!
Will let you know how things pan out.
Keith
I will be taking the ebay option and will get a couple of new ones which I will get the local garage to fit. If that works, great. If not, I may get the LPG conversion transferred to my Mk2 and sell the S type to cover the cost. But I hope not!
Will let you know how things pan out.
Keith
Rough Running
I have had coil plugs 4 and 6 replaced which seems ( so far, and touching wood ) to have solved the problem. Next problem is a split coolant header tank observed on fixing the above. This also has been highlighted by Mike so a very common thread seems to be emerging. It shows the forum is working!
Keith
Keith
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