Intermittent Starting 1989 V12
#1
Intermittent Starting 1989 V12
Spent the winter working n my XJS. Just recently it has developed a problem that I cant seem to figure out. It will start and run until you turn it off, then it won't restart. Let it set and it might start again and it might not. Then all of the sudden it will start again. It has fresh fuel and filter, you can heard the fuel pump running. Seems to be getting spark. Any ideas would be greatly appreciated, I'm missing something but I'm not familiar with the V12 a all.
TIA
TIA
#2
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Intermittents are frustrating. Tests are valid only when performed while the engine is in 'no start' mode. Fortunately for you, that seems to be a frequent occurance.
"Seems to be..." isn't very encouraging
Step one is to positively confirm spark/no spark ...while the engine is in 'no start' mode....before going down any other avenues
Here's some reading
https://www.jaguarforums.com/forum/x...he-v12-178286/
Also, do you have Lucas or Marelli ignition?
Cheers
DD
Seems to be getting spark.
Step one is to positively confirm spark/no spark ...while the engine is in 'no start' mode....before going down any other avenues
Here's some reading
https://www.jaguarforums.com/forum/x...he-v12-178286/
Also, do you have Lucas or Marelli ignition?
Cheers
DD
#3
Hi David
It could be a leaking Diaphragm in the Fuel Pressure Regulator (FPR) on 'B' Bank which may give you enough Fuel Pressure to Start sometimes
And then at other times not
So in a 'Nutshell' a possibility of intermittent Low Fuel Pressure
Or it could be a Blocked or Partially Blocked Fuel Filter always worth changing easy to do and only about £10 (UK)
Or maybe even the Fuel Pump could be on the way out (Aftermarket Generic Pump £30)
again very easy to do
So the First Job would be to Check the Fuel Pressure in the Fuel Rail
A Shop might do that for you for a few dollars or your may be able to borrow a Fuel Pressure Gauge from somewhere
Leaking FPR Diaphragm is sounding quite likely about £50 if you need one and being the one on 'B' Bank its the Cheaper one of the two
The more expensive one on 'A' Bank isn't needed, so that one won't be the problem and can be piped out of the Circuit altogether
So don't go wasting money on a New FPR for 'A' Bank
Fuel Pressure Regulator on 'B' Bank
It could be a leaking Diaphragm in the Fuel Pressure Regulator (FPR) on 'B' Bank which may give you enough Fuel Pressure to Start sometimes
And then at other times not
So in a 'Nutshell' a possibility of intermittent Low Fuel Pressure
Or it could be a Blocked or Partially Blocked Fuel Filter always worth changing easy to do and only about £10 (UK)
Or maybe even the Fuel Pump could be on the way out (Aftermarket Generic Pump £30)
again very easy to do
So the First Job would be to Check the Fuel Pressure in the Fuel Rail
A Shop might do that for you for a few dollars or your may be able to borrow a Fuel Pressure Gauge from somewhere
Leaking FPR Diaphragm is sounding quite likely about £50 if you need one and being the one on 'B' Bank its the Cheaper one of the two
The more expensive one on 'A' Bank isn't needed, so that one won't be the problem and can be piped out of the Circuit altogether
So don't go wasting money on a New FPR for 'A' Bank
Fuel Pressure Regulator on 'B' Bank
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