750i Problem

[Turbofree]

Whilst on the M25 this morning my 750 (1996) lost power and as I moved on the hard shoulder the engine cut out and refused to restart. The RAC checked the fuses, etc and everything was OK and it has a half tank of fuel.

The car turns over briefly but will not start.

Anyone any idea's on what it wrong with it

[m-five]

Could be as simple as a fuel blockage or fuel pump failure, or it could be coils (does the v12 have them?), or it could be an ECU problem.

None of the above are simple to check on the 750, except for the fuel filter, but a dealer/specialist should be able to rule out electronic problems once they plug their computer in!

[Marshy]

Symptoms match what happened to my 730i when the fuel pump went south. Not saying it definitely *is* that, but hey.

If it's the fuel pump, prepare for a wallet-bashing. They're not cheap on the V8s, so god only knows what a pump for the V12 will cost.

[sohlman]

Very likely to be fuel pump or more likely fuel pump relays which are found near the fuse box. Could also be pulse generators which are diodes mounted on the side of the engine/gearbox and provide in your cars case the ECU's with information about the air, Fuel, temperature, revolutions depending on where they are fitted. I would change the fuel pump relays first.

[Turbofree]

All, thanks for the comments and the dealer has just phoned to say the fuel pump is to blame.

[Turbofree]

Marshy, Just out of interest how much did you pay, I have been quoted £459.30?

[Scoobyzoom]

Turbofree,

Just spoke to my guys for you. Take it is the pump in the tank? this is £194.90 plus vat and it takes an hour and a half to fit... (they said there is only one pump)

I make that more like £368 all in...

fleecing coming your way dude!!!

[Turbofree]

Scoobyzoom,

Many thanks for checking this out for me and as to the location of the pump I am unsure. When I pick the car up I will check the bill CAREFULLY!

[Marshy]

If you've an E38 7 series, then you may well find the main pump under the rear seat which, by implication, must be where the fuel tank is located as well. Haul the back seat base out (unless it's electrically adjusted, it'll lift at the front edge then pull out forwards then up). Under there is a black rubbery mat thing, with two round cutouts in it with wires going into the middle of each. Under the drivers' side one should be the pump.

When my pump went south, the RAC man was keen enough to check the electrical supply to the pump, then check out whether fuel was reaching the fuel rails under the bonnet, leading to the right diagnosis of the problem. Top bloke.

[ScoobyZoom]

Turbofree said:

Scoobyzoom, Many thanks for checking this out for me and as to the location of the pump I am unsure. When I pick the car up I will check the bill CAREFULLY!

pleasure TF