X350 R running rich perhaps?
Discussion
When I first bought the car put it straight on the dyno, good power except it was rich. I then went over the car with an oil change, supercharger oil, airfilter (which was absolutely solid with black shyte!) and i'm sure there's a bit more power certainly smoother. Anyhow the exhausts are black inside despite many WOT trips to the redline and lots of 100mile plus trips, few short journeys.
It's going well but when you lift off a bit higher in the revs during acceleration, i.e foot off the floor, you feel a little better acceleration which to my mind means rich running from the old days.
So should I replace 4xO2 sensors and a MAF for about 350 quid all up, reset the ECU and see if it's fixed?
Or is that likely to be a waste of money and better try and diagnose the fault first.
Or do "they all do that, Sir"
Thanks in advance!
SM
115k miles BTW
It's going well but when you lift off a bit higher in the revs during acceleration, i.e foot off the floor, you feel a little better acceleration which to my mind means rich running from the old days.
So should I replace 4xO2 sensors and a MAF for about 350 quid all up, reset the ECU and see if it's fixed?
Or is that likely to be a waste of money and better try and diagnose the fault first.
Or do "they all do that, Sir"
Thanks in advance!
SM
115k miles BTW
SV8Predator said:
You are aware of code readers and vehicle diagnostics?
Yes of course, i'm also aware that I don't have the equipment necessary.Crucially I'm also aware of the fact I won't be the first person to have a suspected slightly rich XJR and the collective knowledge might be a)they all do it or b)we found 9 times out of 10 it was top O2 sensors, c)o2 sensors just fade away at 30,60,90,100k etc.
I'd much rather investigate replacing replace some obvious things that are perhaps in the balance of probability past their best and will have a benefit as a no brainer, or understand this normal before I start.
Hence the post...
I wouldn't just throw random parts at it. Always, always diagnose the fault first.
First make sure you're not harming the car by continuing to run it - any fuelling/ignition related issue might be - and then initially do everything you can that costs nothing.
Is the part load breather clear, are there any loose or leaking pipes or gaskets on the induction system, is the throttle body clean, can you see any signs of loose or broken wires, is full throttle at the pedal actually full throttle at the throttle body, are the plugs good, is the AFM sensor clean, have you disconnected and reconnected all the engine sensor connections to clean them, is the thermostat working and is the cooling system working efficiently?
Just stand and look and think. Has it been modified by anybody and what might that have done? Any more clues in how the problem manifests itself? What does that suggest if you think about it a bit more?
Next beg buy or steal a code reader and read the codes - anything? What's that telling you? You may read a code but what does it actually mean, is that code you've just read actually the problem or is it just a symptom of the problem? Do you have more than one fault and is one of those faults causing the symptoms of a completely different one?
You may have some ancient codes that will lead you astray with your current problem so write them all down then clear them. Take care not to just jump to wild conclusions, but start diagnostics with a clear sheet and a clear mind.
Run the car a bit more and re scan - any codes come back or still all clear?
What's that telling you?
Test and dismiss everything you can yourself then if you're still stuck I'd go back to the guys with the rolling road and see if they can help. If they find a problem you haven't or confirm one you have found but don't want too tackle yourself then and only then is the time to get the spanners out and start replacing stuff.
First make sure you're not harming the car by continuing to run it - any fuelling/ignition related issue might be - and then initially do everything you can that costs nothing.
Is the part load breather clear, are there any loose or leaking pipes or gaskets on the induction system, is the throttle body clean, can you see any signs of loose or broken wires, is full throttle at the pedal actually full throttle at the throttle body, are the plugs good, is the AFM sensor clean, have you disconnected and reconnected all the engine sensor connections to clean them, is the thermostat working and is the cooling system working efficiently?
Just stand and look and think. Has it been modified by anybody and what might that have done? Any more clues in how the problem manifests itself? What does that suggest if you think about it a bit more?
Next beg buy or steal a code reader and read the codes - anything? What's that telling you? You may read a code but what does it actually mean, is that code you've just read actually the problem or is it just a symptom of the problem? Do you have more than one fault and is one of those faults causing the symptoms of a completely different one?
You may have some ancient codes that will lead you astray with your current problem so write them all down then clear them. Take care not to just jump to wild conclusions, but start diagnostics with a clear sheet and a clear mind.
Run the car a bit more and re scan - any codes come back or still all clear?
What's that telling you?
Test and dismiss everything you can yourself then if you're still stuck I'd go back to the guys with the rolling road and see if they can help. If they find a problem you haven't or confirm one you have found but don't want too tackle yourself then and only then is the time to get the spanners out and start replacing stuff.
Jaguar steve said:
I wouldn't just throw random parts at it. Always, always diagnose the fault first.
First make sure you're not harming the car by continuing to run it - any fuelling/ignition related issue might be - and then initially do everything you can that costs nothing.
Is the part load breather clear, are there any loose or leaking pipes or gaskets on the induction system, is the throttle body clean, can you see any signs of loose or broken wires, is full throttle at the pedal actually full throttle at the throttle body, are the plugs good, is the AFM sensor clean, have you disconnected and reconnected all the engine sensor connections to clean them, is the thermostat working and is the cooling system working efficiently?
Just stand and look and think. Has it been modified by anybody and what might that have done? Any more clues in how the problem manifests itself? What does that suggest if you think about it a bit more?
Next beg buy or steal a code reader and read the codes - anything? What's that telling you? You may read a code but what does it actually mean, is that code you've just read actually the problem or is it just a symptom of the problem? Do you have more than one fault and is one of those faults causing the symptoms of a completely different one?
You may have some ancient codes that will lead you astray with your current problem so write them all down then clear them. Take care not to just jump to wild conclusions, but start diagnostics with a clear sheet and a clear mind.
Run the car a bit more and re scan - any codes come back or still all clear?
What's that telling you?
Test and dismiss everything you can yourself then if you're still stuck I'd go back to the guys with the rolling road and see if they can help. If they find a problem you haven't or confirm one you have found but don't want too tackle yourself then and only then is the time to get the spanners out and start replacing stuff.
Now THAT has to rank as one of the most useful posts I've read on here. Many thanks, jobs for the weekend First make sure you're not harming the car by continuing to run it - any fuelling/ignition related issue might be - and then initially do everything you can that costs nothing.
Is the part load breather clear, are there any loose or leaking pipes or gaskets on the induction system, is the throttle body clean, can you see any signs of loose or broken wires, is full throttle at the pedal actually full throttle at the throttle body, are the plugs good, is the AFM sensor clean, have you disconnected and reconnected all the engine sensor connections to clean them, is the thermostat working and is the cooling system working efficiently?
Just stand and look and think. Has it been modified by anybody and what might that have done? Any more clues in how the problem manifests itself? What does that suggest if you think about it a bit more?
Next beg buy or steal a code reader and read the codes - anything? What's that telling you? You may read a code but what does it actually mean, is that code you've just read actually the problem or is it just a symptom of the problem? Do you have more than one fault and is one of those faults causing the symptoms of a completely different one?
You may have some ancient codes that will lead you astray with your current problem so write them all down then clear them. Take care not to just jump to wild conclusions, but start diagnostics with a clear sheet and a clear mind.
Run the car a bit more and re scan - any codes come back or still all clear?
What's that telling you?
Test and dismiss everything you can yourself then if you're still stuck I'd go back to the guys with the rolling road and see if they can help. If they find a problem you haven't or confirm one you have found but don't want too tackle yourself then and only then is the time to get the spanners out and start replacing stuff.
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