Well after a years faultless running a problem has arisen. On the way home the engine management light has come on. No effect on performance and several attempts at restarting have not extinguished it. Any ideas, i have it booked into West riding Jaguar tomos for a plug in. For the past month or so when travelling at 50mph through the never ending road works on the M62, the rev counter fluctuates and it gives the sensation of speeding up and then slowing down ever so slightly. As if there is a fluctuation in fuel delivery or similar. Could this be linked? Any ideas to help me prepare for the inevitable bill greatly appreciated.
Regards
Carl
Engine management light
Moderators:GJS-typeR, Montana5
Re: Engine management light
I`m inclined to wonder if either the throttle body TAC module, throttle position pot or the throttle pedal or their circuits may have an issue. Failure of any one of those three feed backs (out of limits) might give the fault you describe.
As you also say, I suppose it could be a fuel delivery issue with maybe the fuel pressure regulator playing up.
The management light illuminates if there has been a significant recordable event. The light can be extinguished by battery disconnection for 20 mins, buy you will need to reset the radio code and re time the clock. If the engine light comes back on again, then there is a fault. Best to take the guess work out of the equation and have the car scanned.
Perhaps you would let us know the result. Not had this fault on this BB previously so your feed back would be appreciated.
Mike
As you also say, I suppose it could be a fuel delivery issue with maybe the fuel pressure regulator playing up.
The management light illuminates if there has been a significant recordable event. The light can be extinguished by battery disconnection for 20 mins, buy you will need to reset the radio code and re time the clock. If the engine light comes back on again, then there is a fault. Best to take the guess work out of the equation and have the car scanned.
Perhaps you would let us know the result. Not had this fault on this BB previously so your feed back would be appreciated.
Mike
X350 Co-ordinator
2004 XJR
2004 XJR
Re: Engine management light
Hopefully its nothing serious, will let you know. Been running like a dream since the gearbox issue last year. I suppose 1 fault now and then aint bad. Hope its a straight forward fix and not a massive bill like i was threatened with before when the g/box light came on. Hope all is well your end.I`m inclined to wonder if either the throttle body TAC module, throttle position pot or the throttle pedal or their circuits may have an issue. Failure of any one of those three feed backs (out of limits) might give the fault you describe.
As you also say, I suppose it could be a fuel delivery issue with maybe the fuel pressure regulator playing up.
The management light illuminates if there has been a significant recordable event. The light can be extinguished by battery disconnection for 20 mins, buy you will need to reset the radio code and re time the clock. If the engine light comes back on again, then there is a fault. Best to take the guess work out of the equation and have the car scanned.
Perhaps you would let us know the result. Not had this fault on this BB previously so your feed back would be appreciated.
Mike
Carl
Re: Engine management light
The reason for the light on was a faulty MAF sensor. This was causing the fluctuation on the rev s aswell. £75 plus an hours labour. They did find another logged fault. A parking sensor has gone down.......£89.....where do they get their prices from 
Re: Engine management light
Useful to know. Thanks, Phil.
Now we know. Pulsing throttle can be a duff MAF sensor.
The MAF sensor is fitted to the inlet trunking immediately upstream from the airflow meter. It is fixed into the trunking by 4 small torx head screws. Once the unit is lifted out, one can often find a build up on black crank case oil vapour sludge on the hot wires. This can seriously upset engine running if sludge is present. The important thing is not to be tempted to scrape the hot wire with a small screw driver. Even use of a small paint brush is to be avoided. I clean my sensor every couple of years with spray switch cleaner. Time taken for the job is around five minutes.
I`m one for trying to obtain second hand parts from reputable sources ie Eurojag and Neville Anderson being good guys to deal with. Obviously I avoid buying parts that are subject to wear issues such as wheel bearings, water pumps and suspension wishbones etc. Something like a parking sensor bought second hand with a short warranty often makes a sensible alternative to buying new. Generally, second hand prices are around one third of a new unit.
Your points about prices are noted. Parts prices new from Main Dealers can be eye wateringly expensive. For example, rear lower wishbones on an S-type can retail at around £500 each. Neville can often cut prices for those items in half. Same part from the same manufacturer. Just a less greedy supplier.
Whilst on wishbones and bushes, my article on the subject early last year also gave another alternative to buying new. Racing Green Cars can supply new bushes at £56 each (two needed per wishbone). Whilst not a Jaguar approved repair, it is possible with extreme care to change the bushes. The unit I refurbished cost £112 in parts and £40 for my local engine man to remove and replace the bushes using a bench press. So repairs for two wishbones would have cost £304 plus two hours labour to dismantle and refit. Say £500 then all in against a Main Dealer parts price cost of £1000 plus labour and vat.
The savings are there to be had given that time has to be found to research and perhaps run around a bit to achieve those savings. What I would say though is that many issues on the S-type are well known to us here on the Club site and that a few minutes spent on the relevant BB and specific section applicable to the problem, is often time well spent. We don`t know it all, but we know quite a lot!
Anyway, glad you got fixed up.
Mike
Now we know. Pulsing throttle can be a duff MAF sensor.
The MAF sensor is fitted to the inlet trunking immediately upstream from the airflow meter. It is fixed into the trunking by 4 small torx head screws. Once the unit is lifted out, one can often find a build up on black crank case oil vapour sludge on the hot wires. This can seriously upset engine running if sludge is present. The important thing is not to be tempted to scrape the hot wire with a small screw driver. Even use of a small paint brush is to be avoided. I clean my sensor every couple of years with spray switch cleaner. Time taken for the job is around five minutes.
I`m one for trying to obtain second hand parts from reputable sources ie Eurojag and Neville Anderson being good guys to deal with. Obviously I avoid buying parts that are subject to wear issues such as wheel bearings, water pumps and suspension wishbones etc. Something like a parking sensor bought second hand with a short warranty often makes a sensible alternative to buying new. Generally, second hand prices are around one third of a new unit.
Your points about prices are noted. Parts prices new from Main Dealers can be eye wateringly expensive. For example, rear lower wishbones on an S-type can retail at around £500 each. Neville can often cut prices for those items in half. Same part from the same manufacturer. Just a less greedy supplier.
Whilst on wishbones and bushes, my article on the subject early last year also gave another alternative to buying new. Racing Green Cars can supply new bushes at £56 each (two needed per wishbone). Whilst not a Jaguar approved repair, it is possible with extreme care to change the bushes. The unit I refurbished cost £112 in parts and £40 for my local engine man to remove and replace the bushes using a bench press. So repairs for two wishbones would have cost £304 plus two hours labour to dismantle and refit. Say £500 then all in against a Main Dealer parts price cost of £1000 plus labour and vat.
The savings are there to be had given that time has to be found to research and perhaps run around a bit to achieve those savings. What I would say though is that many issues on the S-type are well known to us here on the Club site and that a few minutes spent on the relevant BB and specific section applicable to the problem, is often time well spent. We don`t know it all, but we know quite a lot!
Anyway, glad you got fixed up.
Mike
X350 Co-ordinator
2004 XJR
2004 XJR
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