Fuel pressure /ECU condundrum
Discussion
A strange one I would appreciate any tech advice on :-
having recently reported to a local indy during a routine oil change that the car was running a bit rich from the sooty exhaust deposits & spark plugs, otherwise it was running absolutely fine.
On connection of the fult code reader to the ECU it came up with code 23 'Low Fuel Pressure'. As the car was running okay we agreed to leave until it was quiet in December before investigating. Since then the fuel pressure has been all over the place yesterday on a run out to Loton Park to support the Sprint series.
The question is, can the fault code reader influence a fault or should the ECU be re-set after confirming the code. It seems too much of a coincidence that for a year its exhibited the rich running symptoms without affecting performance and yet immediately aferwards I develop an apparent fuelling issue?
having recently reported to a local indy during a routine oil change that the car was running a bit rich from the sooty exhaust deposits & spark plugs, otherwise it was running absolutely fine.
On connection of the fult code reader to the ECU it came up with code 23 'Low Fuel Pressure'. As the car was running okay we agreed to leave until it was quiet in December before investigating. Since then the fuel pressure has been all over the place yesterday on a run out to Loton Park to support the Sprint series.
The question is, can the fault code reader influence a fault or should the ECU be re-set after confirming the code. It seems too much of a coincidence that for a year its exhibited the rich running symptoms without affecting performance and yet immediately aferwards I develop an apparent fuelling issue?
You could have a loose wire, that only come to light after disconnecting the ECU. depends on the ECU, but I thought the fuel pressure was controlled by a fuel pressure regulator.
Also as most of the early car's was not fully mapable, they could run rich at some points in the map, as running rich is better than week. so its normally a compromise, unless you have a fully mapable ECU.
Also as most of the early car's was not fully mapable, they could run rich at some points in the map, as running rich is better than week. so its normally a compromise, unless you have a fully mapable ECU.
I don`t think you will find a place to fit a pressure guage on the fuel regulator, unless you have fitted an adjustable one, you can however fit one into the fuel rail as there is a valve that can be removed on the drivers side of the rail, and then screw in the guage, the thread should be compatable with most guages which use a 1/8" NPT thread.
I had a similar problem on my griff last week, it turned out to be a faulty AFM, and this was telling the ecu it was receiveing loads of air, so put in more fuel! hence the rich mixture and sooty plugs.
hope this helps.
I had a similar problem on my griff last week, it turned out to be a faulty AFM, and this was telling the ecu it was receiveing loads of air, so put in more fuel! hence the rich mixture and sooty plugs.
hope this helps.
clive f said:
I don`t think you will find a place to fit a pressure guage on the fuel regulator, unless you have fitted an adjustable one, you can however fit one into the fuel rail as there is a valve that can be removed on the drivers side of the rail, and then screw in the guage, the thread should be compatable with most guages which use a 1/8" NPT thread.
I had a similar problem on my griff last week, it turned out to be a faulty AFM, and this was telling the ecu it was receiveing loads of air, so put in more fuel! hence the rich mixture and sooty plugs.
hope this helps.
Which FPR did you use Clive, suspect mine is on it's last legs?I had a similar problem on my griff last week, it turned out to be a faulty AFM, and this was telling the ecu it was receiveing loads of air, so put in more fuel! hence the rich mixture and sooty plugs.
hope this helps.
don`t have the details close to hand at the moment, but I ordered it from a firm called Glencoe, adjustable 1-7bar, came with all the bits to fit into the fuel rail, but you have to make up a bracket to mount it behind the phlenum.
cost around £76 ish.
http://www.fuelsystem.co.uk/ just found them on google.
cost around £76 ish.
http://www.fuelsystem.co.uk/ just found them on google.
Edited by clive f on Wednesday 3rd October 11:07
clive f said:
don`t have the details close to hand at the moment, but I ordered it from a firm called Glencoe, adjustable 1-7bar, came with all the bits to fit into the fuel rail, but you have to make up a bracket to mount it behind the phlenum.
cost around £76 ish.
http://www.fuelsystem.co.uk/ just found them on google.
Cheerscost around £76 ish.
http://www.fuelsystem.co.uk/ just found them on google.
Edited by clive f on Wednesday 3rd October 11:07
If the ECU had a fault code - then the problem is real.
It could get worse any time .. and it sounds like it did !
Could be the regulator or pump or fuel filter blocked.
Sounds like it cannot wait - if it runs lean (lack of fuel) for any amount of time then it could be very bad news for your engine. Best get it sorted ASAP.
It could get worse any time .. and it sounds like it did !
Could be the regulator or pump or fuel filter blocked.
Sounds like it cannot wait - if it runs lean (lack of fuel) for any amount of time then it could be very bad news for your engine. Best get it sorted ASAP.
I hear what you are saying - having noticed the plugs 12 months ago as running rich the car has done 3k since and run absolutely fine. The exact minute i mention this during an oil change & fault code reader connected, the fuelling issue started on the drive home validating the fault code. Far too much of a coincidence i feel and hence my original post.
The fuel filter has been changed within past 12 months and the car has only done 10k so fuel pump should in theory be okay, so i guess the pressure regulator is the first culprit. I guess i need to investigate (and perhaps next time keep my mouth shut during the service - if it ain't broke........)
The fuel filter has been changed within past 12 months and the car has only done 10k so fuel pump should in theory be okay, so i guess the pressure regulator is the first culprit. I guess i need to investigate (and perhaps next time keep my mouth shut during the service - if it ain't broke........)
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