Non starting V8

Hi Guys

I've done a lot of searching on here and Google and not managed to find the same issue.

Last week I went to go out in the Range Rover, started up fine, let it idle for about 10 seconds, reversed back when it spluttered and died and wouldn't restart.

The problem seems to be petrol not getting through to the engine as the plugs seem dry. Plugs all look ok (6 months old) and have got a good spark, air filter is clean and dry, fuel gauge is showing as just under a 1/4 and has been working fine, rotor arm and dizzy look clean and ok.

I've looked at the wiring diagram in case it's an electrical fault, checked the fuses and relays for the fuel pump, inertia cut off switch is no longer in the loop so not that, and the starter turns over so not the inhibit switch. Battery has been charged as well. The fuel pump runs when the ignition is switched as usual for a couple of seconds but doesn't run when turning the starter over (Should it?).

It's an '89 G Reg with the 3.9 EFi engine and had been running fine up until this last week.

Sorry it's a bit long trying to include as much detail as possible!

Si.

dr evil is your man on v8's

thought it was mine! said:

dr evil is your man on v8's

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:hysterically_laughi:hysterically_laughi

Would take a guess at it being a fuel issue, would look at pump first. Pull the fuel pipe offhand see if any fuel comes out when ignition is turned on. Remember if pump is working you will need something to catch the fuel in. Hope this helps.

Does it just refuse to ingnite? I.e is the starter motor spinning but no successful burn? I had an issue with my immobilizer as I had got it wet.

Pump should run to prime the system then stop until cranking, and then the switch in the MAF will indicate the engine is running and keep the relay pulled in ....

As attached....

SnowmanV8 said:

Does it just refuse to ingnite? I.e is the starter motor spinning but no successful burn? I had an issue with my immobilizer as I had got it wet.

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Yes starter spins fine but no burn at all, no immobiliser on mine

Saint.V8 said:

Pump should run to prime the system then stop until cranking, and then the switch in the MAF will indicate the engine is running and keep the relay pulled in ....

As attached....

Click to expand...

Yes it primes when the ignition is switched on and stops, but the relay doesn't click back in when cranking.

Thanks for that page, interesting to read that the ECU doesn't have any part during the starting (I've brought it inside for a few days in case it had got damp)

Thanks.

Saint.V8 said:

Pump should run to prime the system then stop until cranking, and then the switch in the MAF will indicate the engine is running and keep the relay pulled in ....

As attached....

Click to expand...

AFAIK there is no "switch" in the air flow meter. The ECU doesn't do anything until it sees the "engine running" signal which comes from the negative side of the ignition coil. So if there is a good spark but nothing doing with the injection it is likely there is no trigger pulse from the coil because the wire is damaged or corroded or the spade terminal is broken causing the ECU to do nothing at all except just power up and self test.

classic kev said:

AFAIK there is no "switch" in the air flow meter. The ECU doesn't do anything until it sees the "engine running" signal which comes from the negative side of the ignition coil. So if there is a good spark but nothing doing with the injection it is likely there is no trigger pulse from the coil because the wire is damaged or corroded or the spade terminal is broken causing the ECU to do nothing at all except just power up and self test.

Click to expand...

I attached the information from the 1989 Workshop manual....it clearly states a switch in the MAF....

The later models with the revised Lucas EFi system used a small resistor in the LT side of the Coil, so each time it fired a signal was sent to the ECU as the Engine Running signal.....

You are quite correct.....but I think about a revised EFi system!

Saint.V8 said:

I attached the information from the 1989 Workshop manual....it clearly states a switch in the MAF....

The later models with the revised Lucas EFi system used a small resistor in the LT side of the Coil, so each time it fired a signal was sent to the ECU as the Engine Running signal.....

You are quite correct.....but I think about a revised EFi system!

Click to expand...

Ahh ha - I suspect then that the AFM switch refers to flapper? O.P. said this is 3.9 so should be hotwire, I guess the trouble here is '89 was the changeover from 3.5 flapper to 3.9 hotwire (if I remember well?). Anyway, who cares as long as it gets sorted.