More fuel pump problems

[v8griff]

I would pretty much guess the clever folk on here are tired of answering posts on this issue, but I'm getting desperate!!

Long story short, the fuel pump doesn't prime - no 12V at the pump, however the pump jumps into life when I've ran a supply from the battery. So, I'm sure its a wiring issue.

I've read some good stuff in the forums about the connector behind the passenger seat and the cut off switch situated behind the glove box....all stuff I going to check this weekend, however does anyone know what the blue thing/switch is underneath the fuel pump? a black core runs from this thing to the pump, very strange.

I've taken a photo to make it clear:



Help???

[yellowgriff]

This looks like a old fashion serpressor, Bad spelling i know, But anyway this is fitted to stop interfearance on radio.. you used to have these fitted by the coil & atlernator as well... Cheers GOLDIE

[Barreti]

Yep, that was my guess too. I had a black version attached to my fuel pump.

[blitzracing]

If you trouble shooting the fuel pump, the red wire to the lambda probes carries the same 12 volt supply, so its worth checking for power there.

[chrispitman]

I assume the wiring is probably simular to the chimera, if so in the panel behind the seat there are aload of connectors one of these goes to the fuel pump, the connections could be dirty it's worth a try.

[slideways]

have you checked that both the silver relays are working in the loom by the ecu?

[450Nick]

Well it's a pretty simple circuit so there can't be much to try... I would first check continuity between the pump and the silver relay in the passenger footwell. If this is intact and doesn't carry 12v then the problem is further up. This will run through the immobiliser circuit so if there is no continuity then perhaps the immobiliser has a sticking relay. Does the starter motor work? If so then the immobiliser is disarming but perhaps one of the relays is sticking. If all of this works, pull the silver fuel pump relay out and try it with a bit of wire and a 9v battery, check it switches and that you have continuity across it when open. If it's working then move further up. I run an Emerald so my system may well be different but on mine, the fuel pump relay is controlled by an output from the ECU as soon as it recieves power. On the Lucas it's either this or a direct feed from the ignition circuit. So have a look if 12v is being recieved when ignition is switched on. If not, try and trace the wire back to its source, then check continuity to make sure that there aren't any breaks or loose connections. I'm sure by now you will have found something broken or disconnected!

If you look at these things in a methodical way then I'm sure you'll find the problem fairly quickly. Just start at the problem and work back to the other end of the process, checking everything as you go (resistances, continuity, voltage etc) and the problem will soon show its self!

[v8griff]

Hey thanks very much for the replies fellas, much appreciated. Didn't have a chance to look at the weekend, will keep you posted.

Mark.

[buzzsaw]

slideways said:

have you checked that both the silver relays are working in the loom by the ecu?

Seems to be a common failure. One of mine had failed and caused the fuel pump not to prime. Swapping them around didn't help. I prised the aluminium top off the relay and made the circuit manually by holding the relay switch closed, and pump primed. New relay later and all is working! (This is for a Chim, but I would imagine the Griff to be the same)

Edited by buzzsaw on Wednesday 8th April 13:37

[sunwharf]

Had same problem, was the relay.

Cheers
Nick

[griffter]

v8griff said:

Long story short, the fuel pump doesn't prime - no 12V at the pump, however the pump jumps into life when I've ran a supply from the battery. So, I'm sure its a wiring issue.

It doesn't prime, but does the car start and run?

The pump priming and the pump running are different things. The pump will only run with the engine turning over. Even if the pump hasn't primed the pump running as the engine cranks will soon get enough fuel pressure to allow the car to start. Pump priming just helps the engine start more quickly.

The pump priming, on the other hand, is controlled by the ECU. It may be that the wiring to the pump is all OK, but that the priming circuit itself (basically a wire from the ECU - I forget which pin - and the fuel pump relay control -ve) is dodgy.

[spend]

griffter said:

Pump priming just helps the engine start more quickly.

IIRC priming is good in that forces fresh fuel into the fuel rail, hot evaporated fuel caused hot start problems and this overcomes many of those problems (just a memo for the infernal alt-ecu fiddlers)

[v8griff]

Just popped back to give you fellas an update.

I located the 2 silver Bosch relays as suggested (Bosch ref 0332014112) and removed them from the car. Gave them a test this morning and lo and behold one of them wasn't energising. So, looks like I'm getting somewhere.

Off to pick a new relay up tonight....fingers crossed this sorts the problem.

Like to thank everyone who posted, the advice has been invaluable!! hopefully I'm not jumping the gun!

Mark.