UPDATE - Won't start without B+ and FP bridged in diagnostic port (rev 2 turbo)

[toecutter]

Won't start without B+ and FP bridged in diagnostic port to force fuel pump to run. No codes showing.

I checked the COR and fuel pump relays, both operated as they should when power applied (on bench).

Checked various wires for continuity, 12V ect. and all came back fine.

Tried putting back together and it started (without the bridge). Took it out for a run with no problems.

Has sat for a few days since I was out in it, now won't start again without bridge.

What could this be?

[bobhatton]

Won't start without B+ and FP bridged in diagnostic port to force fuel pump to run. No codes showing.

I checked the COR and fuel pump relays, both operated as they should when power applied (on bench).

Checked various wires for continuity, 12V ect. and all came back fine.

Tried putting back together and it started (without the bridge). Took it out for a run with no problems.

Has sat for a few days since I was out in it, now won't start again without bridge.

What could this be?

It is the ECU that controls the fuel pump.
You get fuel when the starter is turning over the engine and then when the engine is running.
Check that the ECU is trying to pull in the relay when you are trying to start the engine.

You will need to check the BGB for the wiring details, I do not have them all in my head.

[2mad]

Check you ecu for popped capacitors mate .. rev2's seem to pop quite regular .. mine did

[toecutter]

Checked ECU capacitors - all OK.

Going by the wiring diagram, the fuel pump relay should be connected to bypass the resistor even with no power supplied. When the ECU powers it, it should switch to go through the resistor. So even if the relay wasn't getting a signal from ECU or wasn't working, the car should still start.

I removed the circuit open relay again to check it's being supplied 12V from the EFI main relay, which it was.

I plugged it back in and it started without the bridge.

Removed COR, then refitted it, wouldn't start.

Removed COR again, pulled top off, checked with 12V supply, capacitor OK ect.

Refitted and now starts. Tried starting a few times in a row and worked fine.

I'm under no illusion that it is fixed, I don't trust it now as it could refuse to start any time.

What could this be?

[2mad]

Checked ECU capacitors - all OK.

Going by the wiring diagram, the fuel pump relay should be connected to bypass the resistor even with no power supplied. When the ECU powers it, it should switch to go through the resistor. So even if the relay wasn't getting a signal from ECU or wasn't working, the car should still start.

I removed the circuit open relay again to check it's being supplied 12V from the EFI main relay, which it was.

I plugged it back in and it started without the bridge.

Removed COR, then refitted it, wouldn't start.

Removed COR again, pulled top off, checked with 12V supply, capacitor OK ect.

Refitted and now starts. Tried starting a few times in a row and worked fine.

I'm under no illusion that it is fixed, I don't trust it now as it could refuse to start any time.

What could this be?

Wish i could help mate electrical gremlins are the worst .. wish i had the time to pop by with my multi meter .. keep plugging away you'll get there

[toecutter]

Yeah it starts every time now, have been trying over a few days.

Suppose I'll just have to use it and take my meter with me.

Does any one know if it's OK to drive with B+ and FP bridged if I need to get home?

[2mad]

Yeah it starts every time now, have been trying over a few days.

Suppose I'll just have to use it and take my meter with me.

Does any one know if it's OK to drive with B+ and FP bridged if I need to get home?

Bgb says no .. but if it gets you home

[toecutter]

Thought I fixed this months ago by cleaning the contact of the CO relay (small amount of carbon on it) as it ran fine afterwards (including a 6hr round trip to Crail strip).

I recently cut out while driving and I had to bridge B+ and FP to get home. It's never cut out while driving before had always been when trying to start.

I checked the COR contact again, was clean but slightly pitted so I fitted a different one but still no start.


I checked the feed from the COR to the fuel pump relay - it does supply voltage when cranking so that rules out the COR.

I then supplied 12V from an external supply to the connection from the FPR to the fuel pump - this made the pump run. Tried the same but going through the resistor - that also worked. So all wiring and the resistor is fine.

I fitted a jumper wire on the connector for the FPR to bypass it, and it started.

This points to the FPR but when bench tested it operates as it should.
The FPR is switched from the ECU to determine whether or not the resistor is used, allowing two pump speeds. The ECU switches it by grounding the live feed somewhere.

The FPR has two positions, either of which should allow the car to start, so even if it was faulty it would still run.

The only thing I can think of is if the ECU was supplying a poor ground to the FPR, making the contact 'hover' between the two sides of the circuit, thus not allowing voltage to pass either way.

Is this possible, and if so how do I check the ECU ground path - I don't know where it grounds through internally? I don't have access to another unit to try. The wire from the FPR connecter to the FPR pin on the ECU checks out OK.

[markstevieandmads]

We had this problem on a v6 conversion which is wired the same.

Bad\loose connection on the cor relay where it connects to fuseboard. Squashed the pins together a bit more after removing fusebox and never had a problem since.

Also not sure if 3vz is same as 3sgte but the afm has a connection to the sump so if the oil goes low then it cuts the cor relay. We found a dodgy sensor so bypassed it temporarily so its possible (if the turbo has the same) you have the same problem.

[toecutter]

The problem seems to be after the COR as it's letting voltage through to the FPR connector plug.

The Turbo dosen't have an oil level sensor.