Fuel pump run on.
Discussion
Hi,
Latest job I’ve done is replacing the fuel sender seal and lock ring which on my car only means siphoning out the petrol and moving the tank, not needing to touch the pipes where they come out of the boot, it’s a pre-cat withside mounted tank sender.
I put some fuel back in and then proceeded to check the gauge was working again as follows as I didn’t want to start the car.
Flashing red immobiliser light by the key goes off when the plug is pushed in then removed, pump can be heard running.
Turn on ignition, gauge goes up, seems all is well, turn off ignition pump continues to run! and immobiliser light stays off! Only way so far is to turn off battery, pulling the ECU plug makes no difference. After re-connecting the battery did the same but started the car and let it idle, then switched off, pump continues to run until bat’ is turned off.
Bit more info, when recently replacing the rad’ I fitted a new heater control valve and while above disconnecting the battery to stop the pump I noticed a little coolant from one of the joints.
So next step is to make sure all the electrics are dry again before trying to find why the pump won’t switch off. When I’m happy all is dry I’ll connect back up and if still getting pump run on I will investigate a faulty fuel pump relay.
Does that sound like a plan.
Latest job I’ve done is replacing the fuel sender seal and lock ring which on my car only means siphoning out the petrol and moving the tank, not needing to touch the pipes where they come out of the boot, it’s a pre-cat withside mounted tank sender.
I put some fuel back in and then proceeded to check the gauge was working again as follows as I didn’t want to start the car.
Flashing red immobiliser light by the key goes off when the plug is pushed in then removed, pump can be heard running.
Turn on ignition, gauge goes up, seems all is well, turn off ignition pump continues to run! and immobiliser light stays off! Only way so far is to turn off battery, pulling the ECU plug makes no difference. After re-connecting the battery did the same but started the car and let it idle, then switched off, pump continues to run until bat’ is turned off.
Bit more info, when recently replacing the rad’ I fitted a new heater control valve and while above disconnecting the battery to stop the pump I noticed a little coolant from one of the joints.
So next step is to make sure all the electrics are dry again before trying to find why the pump won’t switch off. When I’m happy all is dry I’ll connect back up and if still getting pump run on I will investigate a faulty fuel pump relay.
Does that sound like a plan.
Sounds good to me
The thing is, when dried out if the problem has gone away the cause will still need finding, a mix of corrosion and moisture can hold a relay in
Perhaps there's corrosion inside a relay or the fuse-box
Perhaps the problem has been there a while, do you know when it first appeared?
A relay with incorrect terminal configuration will also give this fault (wrong relay)
The thing is, when dried out if the problem has gone away the cause will still need finding, a mix of corrosion and moisture can hold a relay in
Perhaps there's corrosion inside a relay or the fuse-box
Perhaps the problem has been there a while, do you know when it first appeared?
A relay with incorrect terminal configuration will also give this fault (wrong relay)
First a word of warning to all you electrical bods...............If you saw my car and althought the wiring in the pass' foot well is tidy, It has been well reworked by others in its life. For example the Fuel Pump Relay RLFK 30 is no longer in the fuese board.
To add to the 1st post I hadn't noticed that after running the engine and switching off and the pump keeps running, the red led stops off so the engine will restart on the key, don't think that's right.
I also have an intermittent buzz behind the dashboard that comes and goes but have been unable to trace up to now.
Anyway here is a photo of what I think is a modification
This fuse has a "H" marked on its end by someone and has a 30amp inline fuse which is the one I am removing to stop the pump run on.
This fuse is getting warm when the pump is running so I will change it and see what happens. Does the relay look special?
Edit: Is this one?
https://www.ebay.co.uk/itm/4PIN-12V-30-AMP-MAKE-AN...
To add to the 1st post I hadn't noticed that after running the engine and switching off and the pump keeps running, the red led stops off so the engine will restart on the key, don't think that's right.
I also have an intermittent buzz behind the dashboard that comes and goes but have been unable to trace up to now.
Anyway here is a photo of what I think is a modification
This fuse has a "H" marked on its end by someone and has a 30amp inline fuse which is the one I am removing to stop the pump run on.
This fuse is getting warm when the pump is running so I will change it and see what happens. Does the relay look special?
Edit: Is this one?
https://www.ebay.co.uk/itm/4PIN-12V-30-AMP-MAKE-AN...
Edited by lancepar on Tuesday 28th January 16:35
The normal Griffith fuel pump circuit is here:
http://www.bertram-hill.com/fuel-pump-schematic.ht...
The fuel pump relay is not on the fuse box but hangs down as Belle has shown
The relay is not standard as it has a diode across the coil an incorrect relay could cause problems.
From what you say the fuel pump relay is being held in. The relay only normally operates when it receives a " request to run " command ( 0 volts) from the ECU.
The relay obviously has its +12v supply, worth checking if the request to run is there. It could be that the relay is just stuck in the On position.
Best of luck.
http://www.bertram-hill.com/fuel-pump-schematic.ht...
The fuel pump relay is not on the fuse box but hangs down as Belle has shown
The relay is not standard as it has a diode across the coil an incorrect relay could cause problems.
From what you say the fuel pump relay is being held in. The relay only normally operates when it receives a " request to run " command ( 0 volts) from the ECU.
The relay obviously has its +12v supply, worth checking if the request to run is there. It could be that the relay is just stuck in the On position.
Best of luck.
Thanks all, I'm confident things are back to normal.
I replaced the 4pin 30amp relay for a new one.
Thought the buzzing could have been the stepper motor. But decided to clean the plug connections anyway.
Moment of truth starting sequence.
Immobiliser red led extinguished with fob plug, no buzzing, no pump run, turn key to 1st position, pump runs, turn key engine starts.
Turn off engine with key, pump stops, and short delay red led starts flashing.
Replaced relay not getting warm.
Can now finish putting the carpet back round the fuel tank and put everything from the dash I removed.
Cheers
Update.
Photo of replaced relay, the tiny water leak must have migrated down the wires into it.
Edited by lancepar on Wednesday 29th January 14:16
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