Fuel pump relay

FLYING BANANA · 12th April 2020, 14:38

Any reason why this relay should fail less than 6 months since a new one was fitted. Banana would start but then stop. No sound of the pump running So swapped the relay over and the pump was heard. Now runs ok. Got a couple of new ones on there way to me. Going to keep them in the car, just in case.

RogerHeinz57 · 12th April 2020, 15:03

Poor earthing could be the cause of the issues, the relay may be in receipt of a good 12v supply, but if the earth has high resistance, this may result in poor relay operation causing tarnishing of the internal contacts, leading to failed operation.

FLYING BANANA · 12th April 2020, 17:16

1.8t under the bonnet.

SD1too · 12th April 2020, 17:23

Quote:

Originally Posted by FLYING BANANA

1.8t under the bonnet.

Bob,

The fuel pump relay is in the passenger compartment fusebox, not under the bonnet. Is it R4 which has been giving trouble?

Simon

FLYING BANANA · 12th April 2020, 18:41

Quote:

Originally Posted by SD1too

Bob,

The fuel pump relay is in the passenger compartment fusebox, not under the bonnet. Is it R4 which has been giving trouble?

Simon

Well the AA chap last September said it was the fuel pump relay, he plugged her in and came up as a fault on the screen.

There is a single yellow relay next to a smaller black one.
Next row is a faded green one and next to it is the bright new yellow one, this is the one that I swapped over with the cooling fan relay, just like the AA man did.

So what does the R4 one do? Does it stop the fuel pump working?

marinabrian · 12th April 2020, 18:58

Quote:

Originally Posted by FLYING BANANA

Well the AA chap last September said it was the fuel pump relay, he plugged her in and came up as a fault on the screen.

There is a single yellow relay next to a smaller black one.
Next row is a faded green one and next to it is the bright new yellow one, this is the one that I swapped over with the cooling fan relay, just like the AA man did.

So what does the R4 one do? Does it stop the fuel pump working?

Bob, both the AA man, and SD1too are incorrect, the fuel pump relay is in the passenger compartment fusebox, and it is relay 3

I've attached the layout of the relays for you, and as an aside, all of the relays in the hardwired passenger compartment fusebox are the same, so if you suspect a defective fuel pump relay, then you can exchange it for the horn relay......minimal tools, and an easy audible test of the relay functionality

Brian

FLYING BANANA · 12th April 2020, 19:12

So what does the relay do that I have swapped over with? Before the swap no sound from the fuel pump, when changed I can hear the pump and she starts.

FLYING BANANA · 12th April 2020, 19:36

So the R4 relay is at fault then, and not the fuel pump relay? I swapped it with R5 to get her started.

Thanks for your help Brian. Will get it sorted out as soon as the lockdown ceases.

SD1too · 13th April 2020, 08:46

Quote:

Originally Posted by marinabrian

... SD1too are incorrect, the fuel pump relay is in the passenger compartment fusebox ...

Brian,that's exactly what I told Bob prior to your post:

Quote:

Originally Posted by SD1too

The fuel pump relay is in the passenger compartment fusebox ...

I was correct so I think you owe me an apology.

Quote:

Originally Posted by marinabrian

Probably the main relay, without which the ECM is effectively powered down.

Quote:

Originally Posted by FLYING BANANA

So the R4 relay is at fault then, and not the fuel pump relay?

Bob, please note that I alerted you to R4 before MarinaBrian's intervention:

Quote:

Originally Posted by SD1too

Is it R4 which has been giving trouble?

Quote:

Originally Posted by FLYING BANANA

Thanks for your help Brian.

I'm glad to have been of help Bob. Remember, don't believe everything the breakdown services tell you.

Simon

FLYING BANANA · 17th April 2020, 13:01

Relays arrived, the R4, swapped them over and she fired up with no problems. Ran for about 15 minutes then cut out. Refused to fire. Swapped over with another one, got two from Matt, nothing happened. Pump is not running.
Tried again this morning, pump running, started up and she ran for about 3 minutes then died.
Beginning to think it’s the pump itself.

Will have to wait till the local garage re-opens and get the AA to tow her in.

12th April 2020, 14:38	#1
FLYING BANANA Moderator/Club Shop MG ZT 1.8t+. No.3 of 4 in Sunspot Yellow & Ford Fiesta in Black. Join Date: Aug 2010 Location: Rattler Farm Posts: 22,568 Thanks: 9,270 Thanked 15,645 Times in 6,806 Posts	Fuel pump relay Any reason why this relay should fail less than 6 months since a new one was fitted. Banana would start but then stop. No sound of the pump running So swapped the relay over and the pump was heard. Now runs ok. Got a couple of new ones on there way to me. Going to keep them in the car, just in case. __________________ 233,431. That’s our second meet done, no.3 next weekend. onen hag oll

12th April 2020, 17:16	#3
FLYING BANANA Moderator/Club Shop MG ZT 1.8t+. No.3 of 4 in Sunspot Yellow & Ford Fiesta in Black. Join Date: Aug 2010 Location: Rattler Farm Posts: 22,568 Thanks: 9,270 Thanked 15,645 Times in 6,806 Posts	1.8t under the bonnet. __________________ 233,431. That’s our second meet done, no.3 next weekend. onen hag oll

12th April 2020, 19:12	#7
FLYING BANANA Moderator/Club Shop MG ZT 1.8t+. No.3 of 4 in Sunspot Yellow & Ford Fiesta in Black. Join Date: Aug 2010 Location: Rattler Farm Posts: 22,568 Thanks: 9,270 Thanked 15,645 Times in 6,806 Posts	So what does the relay do that I have swapped over with? Before the swap no sound from the fuel pump, when changed I can hear the pump and she starts. __________________ 233,431. That’s our second meet done, no.3 next weekend. onen hag oll

12th April 2020, 19:36	#8
FLYING BANANA Moderator/Club Shop MG ZT 1.8t+. No.3 of 4 in Sunspot Yellow & Ford Fiesta in Black. Join Date: Aug 2010 Location: Rattler Farm Posts: 22,568 Thanks: 9,270 Thanked 15,645 Times in 6,806 Posts	So the R4 relay is at fault then, and not the fuel pump relay? I swapped it with R5 to get her started. Thanks for your help Brian. Will get it sorted out as soon as the lockdown ceases. __________________ 233,431. That’s our second meet done, no.3 next weekend. onen hag oll

17th April 2020, 13:01	#10
FLYING BANANA Moderator/Club Shop MG ZT 1.8t+. No.3 of 4 in Sunspot Yellow & Ford Fiesta in Black. Join Date: Aug 2010 Location: Rattler Farm Posts: 22,568 Thanks: 9,270 Thanked 15,645 Times in 6,806 Posts	Relays arrived, the R4, swapped them over and she fired up with no problems. Ran for about 15 minutes then cut out. Refused to fire. Swapped over with another one, got two from Matt, nothing happened. Pump is not running. Tried again this morning, pump running, started up and she ran for about 3 minutes then died. Beginning to think it’s the pump itself. Will have to wait till the local garage re-opens and get the AA to tow her in. __________________ 233,431. That’s our second meet done, no.3 next weekend. onen hag oll Last edited by FLYING BANANA; 17th April 2020 at 13:02.. Reason: Lost word found

12th April 2020, 15:03	#2
RogerHeinz57 I really should get out more....... A Reasonably Priced Car Join Date: Jan 2014 Location: Burton Latimer Posts: 2,530 Thanks: 408 Thanked 1,064 Times in 712 Posts	Poor earthing could be the cause of the issues, the relay may be in receipt of a good 12v supply, but if the earth has high resistance, this may result in poor relay operation causing tarnishing of the internal contacts, leading to failed operation.