Fuel pump relay

[swmcl]

Hi,

I have a 2011 VE dual fuel 3.6 V6 stock sedan that was a police vehicle. It is stock as far as I know.

I had an issue last week where I ran the kid to school and when I got home and then tried to go out again the car wouldn't fire up.

The car was then sent to a mechanic who charged the earth to find and replace a fuel pump relay. Then at my son's graduation the car failed again with the same symptoms 1 day later.

It is not the relay as such. I have traced the wires and proven the circuit is good surrounding the relay.

I can say there is only 2.5V being applied to the solenoid of the relay from the ECM computer. This is not enough to click the relay. I can say the car runs fine on fuel when I bridge the relay. I can say the signal from ECM to relay shuts down after the post-ignition clunking and whirring after the ignition key is turned off.

Q1. What is doing the clunking and whirring after the ignition is turned off ? There must be a motor and a solenoid involved in purging something or other ??

Q2. Could this clunking and whirring circuitry be supplying the voltage to the ECM for the fuel pump relay circuit ?? ( Given that the fuel pump relay is turned off after the clunking and whirring circuitry does its bit when the motor is turned off )

I have put a tiny amount of conductive grease on the pin of the ECM that goes to the fuel pump relay and also the larger positives (pins 3,5 & 6 of X2 connector) They should be OK.

I can't get to the back of the fuse panel in the passenger kick panel area - I don't know how to remove this fuse panel.

Any experience shared would be appreciated.

Cheers,
Steve

 

[HarryHoudini]

Q1. What is doing the clunking and whirring after the ignition is turned off ? There must be a motor and a solenoid involved in purging something or other ??

Any experience shared would be appreciated.

Cheers,
Steve

I have a 2012 S11 and i get that every so often both when the Ign. is first turned on and sometimes when turned off.
On mine it was the air actuators/flaps going beserk,easy fix for me was too have the Aircon. turned off when starting and stopping,will try and get it sorted properly down the track.
I won't comment further as it will only make your problem fuzzier,local mechanic thinks modern cars have 'Demonic Possession' with the raft of issues they suffer,they are just too complicated,my next car will be a EV.

 

[Fu Manchu]

The fuel pump relay should be a cheap quick replacement taking a few minutes and cost a few dollars for the relay. Unplug. Plug in new one.

The noise you hear is the throttle body. It doesn’t have a cable from the accelerator. It is electronic. The motor opens and closes the butterfly. After you switch off the ignition, it makes a high pitched noise as it recalibrates. The butterfly goes full open, then closed making the shutting noise.

 

[Fu Manchu]

Removing the back of the panel won’t achieve much. It’s a bit tricky to remove and takes some patience to release some tabs. Then you’ll look at it and wonder why you just did it.

 

[Fu Manchu]

It could easily be the key or a security measure. If the key battery is low, the security will stop the injectors from injecting fuel and the car won’t start.

Try that first, because it is only going to cost a few dollars.

Also sounds symptomatic of the good old crank angle sensor having a sook.
Faulty when hot. Works when cold. Car won’t start but will crank.

 

[Fu Manchu]

I have a 2012 S11 and i get that every so often both when the Ign. is first turned on and sometimes when turned off.
On mine it was the air actuators/flaps going beserk,easy fix for me was too have the Aircon. turned off when starting and stopping,will try and get it sorted properly down the track.
I won't comment further as it will only make your problem fuzzier,local mechanic thinks modern cars have 'Demonic Possession' with the raft of issues they suffer,they are just too complicated,my next car will be a EV.

Off topic for OP
I’d be replacing your HVAC module, which is a fairly easy job requiring some patience and care.
They are easy to get from wreckers and you’d pay about $50-80.

Make sure you get either dual zone or single zone depending on your model.

https://forums.justcommodores.com.au/threads/how-to-replace-hvac-module-ve-commodore.213756/

 

[syked]

Just because 1 mechanic says it's the fuel pump relay doesn't mean that is the cause of your problem.

Another thing worth having a look at is the purge valve.
It's on the drivers side of engine towards the rear

 

[HarryHoudini]

Off topic for OP
I’d be replacing your HVAC module, which is a fairly easy job requiring some patience and care.
They are easy to get from wreckers and you’d pay about $50-80.

Make sure you get either dual zone or single zone depending on your model.

https://forums.justcommodores.com.au/threads/how-to-replace-hvac-module-ve-commodore.213756/

Thanks for Info,i'll put it on the 'to-do' list and Post on how it goes.

 

[swmcl]

Cheers guys.

I'm at the point of getting an auto electrician to extend the wires to the relay outside the box so that I can wire up a solution. The car is perfectly normal if the relay is breached. It starts just fine.

Fu, when you say it is rather boring at the back of the fuse box, all I would like to do is join onto the wires of the relay and bring them out to be able to work on them. Is that possible ??

Rgds,

 

[lout]

if you are handy make up some extension wires with male and female spade terminals