300 Tdi failure when accelerating

[Snagger]

Hi folks. I've got a really bad new fault on my 300Tdi (RRC, but there are more Tdi gurus on this forum).

When accelerating hard, the engine stalls and looses all power, resulting in full engine braking. The engine is still running, with no warning lights, surging or roughness. Releasing the throttle immediately restores normal engine operation. Another deep push on the throttle will repeat the failure - only gentle acceleration is possible. This first appeared a couple of times on Monday, but has rapidly deteriorated and now occurs every time the throttle is pushed down. The failure happens within a couple of seconds at about 2500rpm, with the engine hot or cold.

I've had the turbo hoses off, and they're all perfect. Can anyone think of any other cheap possibilities before I look at replacing the injection pump?

[JonS]

If you're flying by wire it might be the throttle position sensor. On my D2 any problems with the tps means it defaults to tickover, which could be what you are experiencing.

Good luck!

Jon

[Snagger]

Tdis use good old fashioned mechanical cables!:D It's a fuel or air problem that kicks in when the power demand is high.

[Budgie]

Lift pump failure sounds a good bet.

The injector pump will suck so much fuel through on it's own but at full thottle it needs the extra push of fuel from the lift pump. If this has failed then you'll get fuel starvation but lift off and it can suck enough through to give you normal running again.

Cheap and easy to change, just remember to get new olives for the fuel lines.;)

Pump is ERR5057 (£17.95 + Vat) and on Paddocks Site (http://www.paddockspares.com/mcp/DISCOVERY_1.html) they say it requires 2x NRC9770 nut and 2x NRC9771 olive.

[Disco69]

Hi,

Have you tried changing the fuel filter ?
If its blocked it could cause these symptoms - Its a good, easy thing to do, before spending lots of money on pumps.

It may be worth checking the fuel pipes for damage too - if the pipes have been flattened or kinked anywhere this will cause a restriction to the flow of fuel.

[lynalldiscovery]

Not so late TDI were full edc control, ie no throttle cable.

Lift pump u/s remove derv filter if less than full pump is weak and requires replacing

Lynall

[ChrisW70]

Check the spill lines between the injectors - I had exactly the same symptoms.
Turned out one of the spill lines had a tiny hole in from rubbing on the soundproof cover and was sucking in air when accelerating but leaking diesel when normal tickover/gentle acceleration.

[adafish]

you ain't 36...:D

[ChrisW70]

You're only jealous cos I'm not follically challenged :clown2:

Still coming Sunday?

[adafish]

na....me motor is shagged again......just fitted a new box and transfer, and the transfer box blew a cog, so i can't make it......never mind i'll promise to do more in the new year...

[Snagger]

Wow Ada, who are all these lovely girls that keep posing for you?:D

I had a good fiddle around with all the suggestions on this thread and the parallel one on the Defender forum. I found no signs of any problems.:confused:

I fitted a warning light sub-circuit to illuminate whenever the fuel solenoid was powered, so that I could see if the fault was electrical by seeing the light go out at the same time as the engine failed. I took the car out for a long test drive with lots of hard accelerating and could not reproduce the fault at all.:confused: It seems to be fixed, touch wood, by accident while investigating. What I don't like is that I never found a specific fault, and so can't trust the apparent improvement. I'll have to see what happens over the next week or so before I start feeling more comfortable with it.

Thanks for all your help guys!:)