Club 80-90 Forums

Hi Guys,

I need to replace my fuel pump on my DJ 2.1 and it says in the Haynes manual to depressurise the fuel system. To do so it says to disconnect the earth lead from the fuel pump and then try to start the engine by "cranking it at the starter motor". What does that mean? You'll have gathered by now I'm a novice

Bit of background, the pump appears to have ceased and caused the wire connecting in to the ECU wiring loom to burn right through and melt some of the wiring in the ECU wiring loom itself. So I will be trying to replace the ECU wiring loom too. There will be no way of starting the motor using the ignition.

Thanks,
Tim.

Just slack off the fuel hose going from the pump up to the pressure regulator (bolted to the inlet plenum) and catch any spill in a rag.

Is it best to do that near the pump or near the regulator?

Out of interest what does crack it on the starter motor mean?

Thanks,
Tim.

If the *pump* is unplugged then cranking it will open the injectors and lose the pressure. TBH I wouldnt fret over it, just slacken a fuel hose clip between the reg and one injector rail

PS i think this depressurizing advice is a hangover from K-Jet systems that use much higher fuel pressures.

That wiring loom burn out sounds serious. I'd have an expert check this all out.
Fuel pumps tend to get noisy and then more noisy. The more noise they make, the less pressure they deliver, but I've not experienced one burning out a loom.
Sounds like something is seriously amiss here. Check that out carefully first.
How about a short circuit in the Cat department!...... (for example). Lambar sensor????

it's a systematic job that requires patience and a good meter unit.
I'd steer towards Bentley's Workshop Manual or as said "an expert'' in this field.
For these sort of electrical problems, it's a matter of 'hands on'.
We can only guess. And my guess is......... a broken or chafing wire, live to earth.
That will burn out a loom in seconds. Strange how the PI system isn't fused>>>?????

Mojoh.

Hi Mojoh,

The auto-electrician suspects the wire coming from the fuel pump may have been chafed at the point where it burned out in the engine bay. When the pump seized it caused a burnout. As the van runs on LPG I was able to keep driving and he thinks that means the wires in the loom became hot. He's suggested replacing the loom and then fitting an in-line fuse on the wire from the pump before it meets the wiring loom. Once the new loom arrives I'm gonna plug it all in and then book him in to make sure everything is in order before firing her up again.

Does that sound like a plan?

Cheers,
Tim.

as you run on lpg and chance you ran the pump dry?

the petrol lubes the pump!

Well the wire burned out when I was returning from the garage having just had the petrol tank replaced. When I got the van back to the garage he changed the filter saying it could have been blocked. Once he changed it and checked it there was no power going to the pump. I later chased that to the burnt out wire. Someone did ask whether the filter had been fitted the right way in my original thread about this. I guess if it had that would stop the petrol going to the pump? I didn't see him fit the new filter so no idea if the one he removed was fitted the wrong way.

Remove the fuel pump fuse and run till it stalls...

Martin

So I'm guess you mean slackening off one of the hoses in the pic linked below? Which one would be the best you think?
Cheers,
Tim.

https://goo.gl/photos/ecbScGt5x9vkZK9C9

timski wrote:Hi Guys,

I need to replace my fuel pump on my DJ 2.1 and it says in the Haynes manual to depressurise the fuel system. To do so it says to disconnect the earth lead from the fuel pump and then try to start the engine by "cranking it at the starter motor". What does that mean? You'll have gathered by now I'm a novice

Bit of background, the pump appears to have ceased and caused the wire connecting in to the ECU wiring loom to burn right through and melt some of the wiring in the ECU wiring loom itself. So I will be trying to replace the ECU wiring loom too. There will be no way of starting the motor using the ignition.

Thanks,
Tim.

As stated...if the pump isn't running (earth or supply disconnected) the engine will start but stall after a few seconds as fuel pressure and supply disappears.

Martin

Thanks Martin but the battery will not be connected until the wiring loom has been repaired so that isn't an option for the time being. Otherwise noted for next time
Tim.

It isn't difficult to jump the starter from a battery independently of the vehicle!