2.5 diesel hard to start hot or cold

Hi all. Just thought that I'd throw this one at you very knowledgeable people on here. I have an early 4 door classic with the 2.5 M51 diesel fitted and I am having trouble getting it to start hot or cold. I have fitted 6 new glow plugs and also put a non-return valve on the fuel line after the fuel filter as I noticed the fuel was leaking back to the tank leaving the fuel lines empty after a while. She will start eventually after cranking over for 10 seconds or so. Then when I turn her off after a drive when she is warmed up, if I go to start her immediately it's the same again. Cranking for 10 seconds or thereabouts before it will fire. It has an iveco truck intercooler fitted so I would imagine the pump has been turned up, it's a manual injector pump by the way and it throws out plenty of black smoke on acceleration. Does turning up the injector pump on a diesel cause poor starting problems?.....

Thanks all.

I had a Disco that did some thing simular before the injection pump gave up... Try having it turned down..

I take it this is a P38 Range Rover and not a Classic Range Rover.
Try doing a search as I believe this is a common problem and kits are available for it.
Cant help much more than that I'm afraid.

ruffday said:

I take it this is a P38 Range Rover and not a Classic Range Rover.
Try doing a search as I believe this is a common problem and kits are available for it.
Cant help much more than that I'm afraid.

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Thanks for responding guys.....No, It's an early 1982 4 door classic with the M51 p38 diesel engine fitted. The kits you are referring to are hot start kits to fool the becm into thinking the engine is cold and thus powering the glow plugs to give better hot starting. My issue is different. It's a hot and cold start problem. I'm hoping it's not a worn injector pump. I don't think it is as once started, it runs very well with no issues across the rev range and no lumpiness or flat spots. I have reposted this in the correct thread now.....Thanks.

Don't know if this helps but I recently bought a BMW 525tds (same engine) and that was the same as you have just described. I too changed the glow plugs as they were all shot but I also changed the fuel filter and the pump in the tank. Now she starts on the button (when the glow plug lights go out).

I don't know if the Range Rover has a lift pump or similar but maybe it's worth checking the fuel delivery for effectiveness and/or possible air getting in. Might be worth changing the fuel filter too.

I have also heard about the injector pump seals failing so that might be a consideration but I would imagine that would just leak fuel all over the injection pump.

tetsu0san said:

Don't know if this helps but I recently bought a BMW 525tds (same engine) and that was the same as you have just described. I too changed the glow plugs as they were all shot but I also changed the fuel filter and the pump in the tank. Now she starts on the button (when the glow plug lights go out).

I don't know if the Range Rover has a lift pump or similar but maybe it's worth checking the fuel delivery for effectiveness and/or possible air getting in. Might be worth changing the fuel filter too.

I have also heard about the injector pump seals failing so that might be a consideration but I would imagine that would just leak fuel all over the injection pump.

Click to expand...

Some very good points there tetsu0san....My suspicion is the original petrol electric pump near the tank is not up to the fuel delivery rate. Like I said, once she fires up the injector pump takes over and sucks the amount of fuel required in order to sustain itself. It also belches out black smoke on acceleration as I suspect that the fueling has been tweeked. This in itself would suggest that the injector pump is healthy and delivering loads of fuel. I would like to know the fuel delivery rate of a P38/BMW Tds in tank electric pump just to make a comparison.....

Cheers for the response.