Engine will not start after rebuild - suspect electrickery.

Think you need to print out all this "how to"

 

Yes but by moving the flap whilstthe ignition is on (in the run position)you are simulating air flow which in turn energizes the fuel pump.

 

if i do this and the pump doesn't run then what will it point to, bearing in mind we know the pump works and the power wire from the relay to the pump is complete and has tested for continuity.

 

I would say it would be a bad connection at the dual relay or the relay itself, did you do any measurements at the dual relay last night? I can't remember

 

Agree with that, it must be in the run position for it to work...

However, what does it really prove that we don't already know? If the pump works then it shows the connection from AFM to relay back to pump works so all this does is confirms that the problem is from starter to fuel pump. As it is such a quick test to do it can't hurt to do it, but as you have already tested that the wire from DR to pump works all you are testing is the wire from AFM to relay. This doesn't need testing until the engine fires up, if the engine stays running after letting go of the ignition key in the run position then the wire is working, if it doesn't, then check the wire.

I agree, seems most likely...

So what do we now know from the testing:



This shows that 12v is getting to the DR on cranking, 12v is getting to the AAR so it is passing the voltage through but there is no voltage at 88D - the fuel pump connector.

Therefore, it's either the relay connector at 88D or the wire to the fuel pump. As you have pulsed the wire from 88D to the pump and it worked we can say that the wire is fine, leaving only the connector.

The other thing that we also need to test to be 100% sure is that we need to do one more test, (sorry should have got you to do it yesterday):

Crank the engine and test for voltage between 86A and 85.

If you get 12v then it's definitely the relay itself that is at fault
If you get 0v then you have a problem in the wire between the starter and the DR slot 86A

So, the testing has narrowed it down a lot, just a one more things to try and then we have a solution.

Get the pump to whirr so we know the FI system is working as it should then we can see if it fires up or if we need to work on an airlock.

 

@Moons does that above make sense to you?
sorry not been on today guys busy at work and fed up of van so was having a break from questions, your help is much appreciated all of you thanks a lot

 

The 76 FI bus I had Ricky had loads of brittle wires which failed when I started poking at stuff. The cold start valve was the worst as it is a really right squeeze with not much wore left to pull on. Also as I said above I'm sure it was a loose pipe, not wire, to the AFM which prevented the fuel pump from triggering, so it's possible that you've got an electrical symptom caused by a mechanical problem

 

i'm going tomorrow, please explain how i check the voltage between 86a and 85.

 

Voltmeter on V DC black probe on the connector plug for 85 and the red probe on 86a. Leave it all plugged in and push the probes onto the back of the plug. Will do a PIC if you want

 

please mate. do i crank it or ignition on so lights on only?

 

I'd of thought try with ignition off and then again with it on. I suppose whilst cranking it also won't hurt.

 

prob is i'll be on my own most of the day so it could be awkward lol

 

Will that's ignition on and off sorted then.

Try and stick the gauge through the hatch and then whilst turning it over you might be able to look over your shoulder and see it move.

Careful you don't flatten your battery.

 

eddie has a jump start thing but i'll take my leads and hook my caddy to it as well.

 

Yes while cranking, just checked mine. Showed about 8 -9 volts

The 85 is just earth so any earth is fine but you could still check with 85 as well to confirm it isn't bad.


This is am example of how to back probe, this is actually 86a

 

Good luck tomorrow, wish I was back to working 3 days with this weather - I'd of come and helped.

 

doesn't he other plug need to be in to test?

 

that's one good thing it's supposed to be red hot all weekend

 

Not if its just an earth wire.

 

Not if you haven't got it going it won't be.

Will you take the Mrs and camp there the weekend?