P38 2.5TDI won't start

Kelvin'D-MiC' · Jul 16, 2024

Hello there guys. I have a P38 2.5TDi and the issue is after starting it and warming up the engine. When I drive a bit of a distance that gets the engine optimum and I switch the engine off.....the car won't start unless I leave it to cool down or I push start it. What could be need of attention?

Datatek · Jul 16, 2024

Kelvin'D-MiC' said:
Hello there guys. I have a P38 2.5TDi and the issue is after starting it and warming up the engine. When I drive a bit of a distance that gets the engine optimum and I switch the engine off.....the car won't start unless I leave it to cool down or I push start it. What could be need of attention?

FIP timing or possibly a leak off pipe leaking. My money would be on FIP timing beng out due to chain stretch. Needs diagnostics to check the modulation which should be 50% with the engine temperature at 95C.

Kelvin'D-MiC' · Jul 16, 2024

Datatek said:
FIP timing or possibly a leak off pipe leaking. My money would be on FIP timing beng out due to chain stretch. Needs diagnostics to check the modulation which should be 50% with the engine temperature at 95C.

Okay thank you very much. That just sounds a bit complex for me at the moment lol. Nothing simple as retard or advance?

Datatek · Jul 16, 2024

Kelvin'D-MiC' said:
Okay thank you very much. That just sounds a bit complex for me at the moment lol. Nothing simple as retard or advance?

You could try loosening the FIP mounting bolts and tapping it a small amount towards the engine block. A bit hit and miss but might work.

Kelvin'D-MiC' · Jul 16, 2024

Datatek said:
You could try loosening the FIP mounting bolts and tapping it a small amount towards the engine block. A bit hit and miss but might work.

Okay thanks will give that a try when I replace my glow plugs.

Rubberknees · Jul 16, 2024

Kelvin'D-MiC' said:
Okay thanks will give that a try when I replace my glow plugs.

The small amount mentioned will be 1/8th inch to 3/16th for the first attempt

Rangieman123 · Jul 16, 2024

Your timing chain has stretched. Advancing the pump on its mounts can help but is not perfect as your ECU ultimately controls pump timing. You can also search online for P38 hot start kit, which is basically a small resistor in a box which fools the engine's ECU into thinking you're on the North Pole and advances the pump timing until it starts.
Funnily enough, the BMW 525 tds didn't suffer with this problem (same engine as your P38) so maybe BMW anticipated this issue.....

Datatek · Jul 17, 2024

Rangieman123 said:
Your timing chain has stretched. Advancing the pump on its mounts can help but is not perfect as your ECU ultimately controls pump timing. You can also search online for P38 hot start kit, which is basically a small resistor in a box which fools the engine's ECU into thinking you're on the North Pole and advances the pump timing until it starts.
Funnily enough, the BMW 525 tds didn't suffer with this problem (same engine as your P38) so maybe BMW anticipated this issue.....

The hot start fix is a bodge to cover up timing chain stretch, it simply implements cold start fueling it does not affect the timing. Re-timing the FIP does the job properly and cures the hot start problem. The ECU does not control the mechanical timing of the pump, it's electronic control is within small limits so if the mechanical timing is out, the ECU cannot compensate.

Kelvin'D-MiC' · Jul 17, 2024

Lovely stuff guys thank you for bit more insight to that, will give that shot and see how that helps and will give feedback after attempt. All this will be DIY attempts from a novice point of view.

P38 2.5TDI won't start

Kelvin'D-MiC'

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Datatek

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Kelvin'D-MiC'

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Datatek

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Kelvin'D-MiC'

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Rubberknees

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Rangieman123

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Datatek

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Kelvin'D-MiC'

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