Fuel Pump not priming - not the inertia switch
Discussion
chris1972 said:
Oldred_V8S said:
This will not work, the two are interlinked.
They're the same no?Like I say they are linked, it is better to get a replacement and swap that in turn.
If you run a 12V wire straight from the battery to the fuel pump relay "trigger" with the ignition on does that make the fuel pump run? That way you are testing all of the wiring for the fuel pump circuit.
If it does then you COULD just select an ignition switched 12V line and bypass the fuel pump part of the immobiliser - either temporarily or more permenantly.
In the past many of the issues I have had with cars that have sat for a while are down to frozen relays and the bizarre way TVR wired up the immobiliser relays (backwards) probably doesn't help...
If it does then you COULD just select an ignition switched 12V line and bypass the fuel pump part of the immobiliser - either temporarily or more permenantly.
In the past many of the issues I have had with cars that have sat for a while are down to frozen relays and the bizarre way TVR wired up the immobiliser relays (backwards) probably doesn't help...
Oldred_V8S said:
Exactly the same but they are linked, say we have a faulty ECU relay, this will give the impression of the a failed pump relay. If you then swap them, the faulty ECU relay is now on the pump, giving the same symptoms.
Like I say they are linked, it is better to get a replacement and swap that in turn.
Had tried swapping them round but to no avail.Like I say they are linked, it is better to get a replacement and swap that in turn.
Julesprivate said:
If you run a 12V wire straight from the battery to the fuel pump relay "trigger" with the ignition on does that make the fuel pump run? That way you are testing all of the wiring for the fuel pump circuit.
If it does then you COULD just select an ignition switched 12V line and bypass the fuel pump part of the immobiliser - either temporarily or more permenantly.
In the past many of the issues I have had with cars that have sat for a while are down to frozen relays and the bizarre way TVR wired up the immobiliser relays (backwards) probably doesn't help...
That's a good idea, however it didn't occur to me at the time, having tried direct to the pump and now don't have access to the car as it's getting looked at. Only other thing is, it wasn't clear to me which pin was which. If it does then you COULD just select an ignition switched 12V line and bypass the fuel pump part of the immobiliser - either temporarily or more permenantly.
In the past many of the issues I have had with cars that have sat for a while are down to frozen relays and the bizarre way TVR wired up the immobiliser relays (backwards) probably doesn't help...
I did test the voltage at all the pins of the relay, and there was no change when the ignition went on, so it seemed to me that there was no signal getting to the relay telling it to switch in the first place.
Aussie John said:
If it was the pump relay you were measuring then it's probably the ecu relay that's the problem
That's an interesting point, thanks, just trying to remember what I did test.I can't remember for sure, but I'm pretty sure I measured it with different relays. I'd measured it, swapped them over then measured again. It was Sunday I did it and my brain has been frazzled by work since then, but i'm pretty sure both relays were tested as being in the fuel pump relay position.
In that situation, a broken ecu relay would only have provided these results on one of the two tests.
Sadly, it's a bit academic though as it's now with an expert, waiting to be seen on Monday. I'll let you know what the outcome is.
Edited by KennyAbarth on Thursday 20th June 22:56
KennyAbarth said:
Aussie John said:
If it was the pump relay you were measuring then it's probably the ecu relay that's the problem
That's an interesting point, thanks, just trying to remember what I did test.I can't remember for sure, but I'm pretty sure I measured it with different relays. I'd measured it, swapped them over then measured again. It was Sunday I did it and my brain has been frazzled by work since then, but i'm pretty sure both relays were tested as being in the fuel pump relay position.
In that situation, a broken ecu relay would only have provided these results on one of the two tests.
Sadly, it's a bit academic though as it's now with an expert, waiting to be seen on Monday. I'll let you know what the outcome is.
Edited by KennyAbarth on Thursday 20th June 22:56
That was my point above. Swapping the relays will give the same symptoms even if only one of the relays was faulty.
Aussie John said:
Sometimes just giving them a shake will make them work for a bit but they will be on the way out.
This I had a sticky relay after a winter lay-up last year, I could not hear it clicking but after giving it a shake it started working again, now I try an cycle all mechanical and electrical items on a regular basis during the winter. I've got a sulky indicator switch that stops working if I ignore it for too long, as well.
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