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Discussion Starter #1
Hello,1990 RRC (Lucas 14CUX) brought to our workshop ,when you turn ignition ON ,fuel pump runs continuously!(not doing that 3 sec common energizing!)the engine performs poor in demanding loads. i reckon the pressure does not build-up in rail! any similar experience?RegardsMassoud
 

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1970-1995 Range Rover Classic
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Do you have the means to do a pressure test on the system? Read this: http://www.landroversonly.com/forums...classic-47581/

I would want to try to determine why the pump is not shutting off after the 3 second priming phase. From what I can tell in your post, the truck will start and run? But it is running badly? Or will it not start at all?

It's not clear what you are trying to say with "Hotwire continues fuel pump run!"………..are you saying that you are running a hot lead from the positive terminal of the battery to the fuel pump or what? If you are doing that, then perhaps that could be why the fuel pump runs continuously before the truck is cranked.

Among other things, check the IAC valve at the plenum and the fuel pressure regulator also at the plenum.

I just went through an ugly issue with fuel flow that was very difficult to solve - see this thread:

http://www.rangerovers.net/forum/8-range-rover-classic/127793-93-rrc-swb-fuel-pump-replaced-starts-but-wont-stay-running.html

Good luck to you.

SMD
 

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Discussion Starter #3
Hi again,

"Hotwire" refers to "Lucas Hotwire ".
that verb "Continues" should've been "Continuous" ! (dumb intelligence of smartphones!)

Yes ,engine runs ,and it won't stall or sth ,only its poor on heavy loads (e.g. highway ascensions)

i guess the required pressure does not build up back of injectors.(pressure regulator is my prime suspect)

i'll test inline pressure in next few days and reflect results here.

Thanks for your response.

Regards
Mass
 

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1995-2002 Range Rover P38A
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The fuel pump is controlled by the ecu. It runs for three seconds on start up to pressurise and then it runs once it gets a signal from the coil that the motor is turning. Once the motor is going, the pump runs continuously pumping fuel through the return line back to the tank. The pressure in the rail is regulated by a relief valve on the end of the rail at the return line. It has a vacuum actuator on it which varies the valve opening to maintain a constant pressure differential between the rail pressure and the manifold pressure.

If you turn the ignition on without starting the motor, you should hear the pump running for three seconds and then stop. If it doesn't, there could be a short somewhere, or else there could be an ecu problem. Lack of guts on a hill or acceleration could be a blocked filter or maybe some garbage in the mesh bag on the pump inlet.
 

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Discussion Starter #5
The fuel pump is controlled by the ecu. It runs for three seconds on start up to pressurise and then it runs once it gets a signal from the coil that the motor is turning. Once the motor is going, the pump runs continuously pumping fuel through the return line back to the tank. The pressure in the rail is regulated by a relief valve on the end of the rail at the return line. It has a vacuum actuator on it which varies the valve opening to maintain a constant pressure differential between the rail pressure and the manifold pressure.

If you turn the ignition on without starting the motor, you should hear the pump running for three seconds and then stop. If it doesn't, there could be a short somewhere, or else there could be an ecu problem. Lack of guts on a hill or acceleration could be a blocked filter or maybe some garbage in the mesh bag on the pump inlet.

Hi John,

yep i know the idea of whole system btw thanks for reminding me.
when i turn the switch in Position II there must be pressurizing stage of pump and then the cut-off sound ,the problem is the pump works continuously .either the canister valve release to return pipe or the pump itself might be weakened!

there was no fault code indicating valve stuck open or sth...!


Regards
Mass
 

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It's a time cut off not a pressure cut off as far as I know, so if it's not cutting off then it sounds like an ecu problem, unless the relay is stuck on - seems unlikely but have you swapped the relay?
I had a look at the wiring diagram and I can't see how a short could lead to the pump running continuously.
 

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Discussion Starter #7
i found some rewiring around purge valve !
also reckon there might be some other modifications ! (i've to inspect steering column,guess there might be shortcut to fuel-pump rather than ECU's command line)

stay tuned ,i'll be back with news.:wink:
 
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