Ph1 172 cut out and now wont start

[B-shaw557]

So Monday just gone I was at curborough sprint course, 1/4 way into my 2nd run the car just died on me.
Checked all the usual bits, inertia switch fine,nothing looked to have come loose, fuses all fine

We noticed the fuel pump isnt priming or even coming on when turning over.
We managed to get this to come on when bridging the connections where the relay plugs in.

I have replaced the Crank position sensor, as this is what everyone said it sounded like the problem was.
I have fitted a new fuel pump relay

Still, the car refuses to do anything, fuel pump still isnt priming.
Everything still turns over fine, imob light isnt flashing any different, the car will turn over for aslong as you hold the key there.

What else should I start checking?

One thing I don't understand is electrics, goes over the top of my head, guess I'm about to learn though 😂

 

[Ant1]

You checked the rail is getting fuel? You checked the plugs are getting spark? This is what I would be checking.

If you have spark and fuel at the rail then you have a belt problem.

 

[White16valver]

I was going to say it could be a loose earth strap, but if the fuel pump is operational but is not working when turning the car over, it's not getting power.

Do you have a second key you can try? IIRC the immobiliser rings can fail, meaning it won't switch the immobiliser off, so if it's not a failed key, it could be worth swapping a new immobiliser ring in.

(IIRC...)

 

[JamesBryan]

Definitely made sure the inertia switch is fine?

 

[B-shaw557]

Definitely made sure the inertia switch is fine?

I have a spare I can try, I'll give that I a go tonight.

 

[B-shaw557]

I was going to say it could be a loose earth strap, but if the fuel pump is operational but is not working when turning the car over, it's not getting power.

Do you have a second key you can try? IIRC the immobiliser rings can fail, meaning it won't switch the immobiliser off, so if it's not a failed key, it could be worth swapping a new immobiliser ring in.

(IIRC...)

I have a spare that unlocks the doors but won't start it.
I guess I could try that to see if it does anything different to the one I'm using. I'm sure that only let's you turn over a handful of times before cutting.

 

[White16valver]

Hope you can sort it!

Can you plug it in and see if there are any codes coming up?

 

[B-shaw557]

Tonight's update
It's all a bit weird 😂
So, swapped inertia switch, no difference
Bridged the conections, same.
Tested continuety on the new plug I connected for cps, just incase connection was shitty, was fine.
All earth's getting continuety
Related fuses same
Checked for spark, nothing.
Now for the odd bit.
The pump is getting 12v, as is the coil pack when ignition is on. However neither are actually doing anything.
Checked continuety between the ecu and the signal wires to the relays, all fine.
Fuel pump will still work when the connection is bridged at the relay.

Now, to repeat that as people on fb seemed unable to grasp this 😂

With all plugged in as normal, ie relay, the multimeter reads 12v at both coil pack and fuel pump when the iginitjon is switched on.
HOWEVER, NEITHER ARE DOING ANYTHING LIKE THIS
Only when you bridge the connection at the relay, bypassing the switch so its always on, with a bit of wire, does the fuel pump work.

Both plugs reading 12v on iginition
Neither doing anything
Pump works when connections bridged

 

[JamesBryan]

Beyond my electrical knowledge, but if it's working when you bridge the connection then you need to focus on that area.

 

[NorthloopCup]

The pump and coil pack receive 12v as it’s switched by the earth.
Have you checked all the ecu earth points on the gearbox etc?

If it doesn’t get an earth it will do nothing.

 

[B-shaw557]

Where are all the earth points?
I know there's a main earth from chassis to box on the side/in wheelarch area
One I broke when doing the pas pipes, but I reconnected it, that still looked fine as it did cross my mind.
That was on top of the box going into the main loom.
Any others?

 

[NorthloopCup]

Where are all the earth points?
I know there's a main earth from chassis to box on the side/in wheelarch area
One I broke when doing the pas pipes, but I reconnected it, that still looked fine as it did cross my mind.
That was on top of the box going into the main loom.
Any others?

I’m pretty sure that’s the main one for the ecu, so you need to be checking each one to make sure it’s connected. Volt drop is a good way to test them individually at the ecu plug. You’re looking for around 0.01-0.03.
Don’t resistance test them with the ecu connected - you’ll not make the ecu very happy if you do. 😂