P38 2.5 Diesel - running issues

AOK62 · Sep 26, 2023

This P38 is a 01 with 104k miles, auto transmission. It is in the process of being recommissioned after sitting for a number of years. Engine starts and runs. However, it does not run well and I have noted the following:
- Revs at start-up are about 1000 and drop back to 820 after a few seconds.
- Idle revs remain at 820 even when warm.
- Max revs when accelerator is on the floor is 2900.
- Lots of white smoke at full revs.
- Injected fuel quantity is approx 7.0 mg/s at idle using Hawkeye diagnostics.
- Start of injection is -3.0 deg on Hawkeye diagnostics.
- Engine 'splutters' a bit. Not running smoothly.

Any information on the best route to follow would be greatly appreciated.

brianp38dse · Sep 26, 2023

Check the map pipe from under the inlet to the sensor on the fuel filter is not blocked or split
and a word to the wise calling it a J**P is not good form on here.
And Hello and welcome

AOK62 · Sep 26, 2023

brianp38dse said:
Check the map pipe from under the inlet to the sensor on the fuel filter is not blocked or split
and a word to the wise calling it a J**P is not good form on here.
And Hello and welcome

Slap on the hand accepted.......

Thanks for the info.
Pipe from inlet to fuel filter is new.

Datatek · Sep 26, 2023

AOK62 said:
Slap on the hand accepted.......
Thanks for the info.
Pipe from inlet to fuel filter is new.

Check the spigot on the manifold is not blocked. 820 rpm at idle when up to temperature is within spec, It is also normal for the revs to be higher after starting when cold. The white smoke might just be condensation accumulated over time if it has not been used.

Grrrrrr · Sep 27, 2023

AOK62 said:
This P38 is a 01 with 104k miles, auto transmission. It is in the process of being recommissioned after sitting for a number of years. Engine starts and runs. However, it does not run well and I have noted the following:
- Revs at start-up are about 1000 and drop back to 820 after a few seconds.
- Idle revs remain at 820 even when warm.
- Max revs when accelerator is on the floor is 2900.
- Lots of white smoke at full revs.
- Injected fuel quantity is approx 7.0 mg/s at idle using Hawkeye diagnostics.
- Start of injection is -3.0 deg on Hawkeye diagnostics.
- Engine 'splutters' a bit. Not running smoothly.

Any information on the best route to follow would be greatly appreciated.

2900 revs sounds like limp mode but that might just be a weak battery or bad connector somewhere. Damp gets in absolutely everywhere when they stand and they don't like damp.

The only other thing I can see causing white smoke is a cracked head with water leaking across. Compression test or pressurising each cylinder in turn through the glowplug hole with the valves shut and the expansion tank cap off should show up any issues there.

Mark Piercy · Sep 27, 2023

It could be the throttle mechanism sticking in the pump head and gummed up

Do a sniff test with gas detection kit before pulling a ton of stuff of it.
Also fill the coolant tank to the top, run and watch for bubbles.
There may well be a ton of condensation in the exhaust like Keith suggests.
@Grrrrrr , ive never seen a limp mode on these kiddo

Coolant check,
Fresh diesel and let it run for a while.

stemac33 · Sep 27, 2023

Is white smoke not unburnt diesel, could be a gummed up injector(s)

Grrrrrr · Sep 27, 2023

Mark Piercy said:
It could be the throttle mechanism sticking in the pump head and gummed up
Do a sniff test with gas detection kit before pulling a ton of stuff of it.
Also fill the coolant tank to the top, run and watch for bubbles.
There may well be a ton of condensation in the exhaust like Keith suggests.
@Grrrrrr , ive never seen a limp mode on these kiddo
Coolant check,
Fresh diesel and let it run for a while.

I think the petrol limits the revs in some instances, the GEMS at least. Pretty sure we had on MrGorsky's one at some stage. Not got enough experience of the auto diesel but I would imagine it is similar.

White smoke could indeed be diesel and a stuck injector although I think you would hear it.

This guide is rather useful: https://learndiesels.com/diesel-smoke-guide/

Datatek · Sep 27, 2023

Mark Piercy said:
It could be the throttle mechanism sticking in the pump head and gummed up
Do a sniff test with gas detection kit before pulling a ton of stuff of it.
Also fill the coolant tank to the top, run and watch for bubbles.
There may well be a ton of condensation in the exhaust like Keith suggests.
@Grrrrrr , ive never seen a limp mode on these kiddo
Coolant check,
Fresh diesel and let it run for a while.

Limp mode certainly limits revs and power, don't ask me how I know

RangeRoller dt · Sep 27, 2023

Driving around with an ejected water pump put mine in limp mode. Unmistakable once you’ve experienced it

Mark Piercy · Sep 27, 2023

RangeRoller dt said:
Driving around with an ejected water pump put mine in limp mode. Unmistakable once you’ve experienced it

That's called a seizure

Mark Piercy · Sep 27, 2023

Datatek said:
Limp mode certainly limits revs and power, don't ask me how I know

I'd say, sticking turbo actuator or sticky pump head. Weirdly when the aircon is on

AOK62 · Oct 16, 2023

Mark Piercy said:
I'd say, sticking turbo actuator or sticky pump head. Weirdly when the aircon is on

Just to update on this problem.

I pulled the injectors and had them checked. All were ok.
Main problem is still the amount of white smoke both at idle and when revved.
If this is an injector pump issue what is the best way to troubleshoot.
Thanks.

Mark Piercy · Oct 16, 2023

AOK62 said:
Just to update on this problem.

I pulled the injectors and had them checked. All were ok.
Main problem is still the amount of white smoke both at idle and when revved.
If this is an injector pump issue what is the best way to troubleshoot.
Thanks.

Does the white smoke smell at all?
If it was over fueling the smoke would smell really strongly of diesel.
Have you checked for emissions in the coolant tank?

Datatek · Oct 17, 2023

Mark Piercy said:
Does the white smoke smell at all?
If it was over fueling the smoke would smell really strongly of diesel.
Have you checked for emissions in the coolant tank?

And the smoke would be black not white.

Grrrrrr · Oct 17, 2023

AOK62 said:
Just to update on this problem.

I pulled the injectors and had them checked. All were ok.
Main problem is still the amount of white smoke both at idle and when revved.
If this is an injector pump issue what is the best way to troubleshoot.
Thanks.

Static timing is set using a dial guage as per RAVE. After that it is a specialist job if the FIP itself is acting up. You can get a refurbed pump from Diesel Jones in Manchester but at £650 you want to make sure it really is that.

Is the coolant pressurising at all? You can make an adapter for the glow-plug holes and use an airline or a bike pump to pressurise each cylinder with the valves shut (take the cam cover off so you can check both inlet and exhaust ate shut) and see if any coolant pushes out. If it does then either head gasket or more likely cracked head. If no issues then back to FIP.

RangeRoller dt · Oct 17, 2023

AOK62 said:
If this is an injector pump issue what is the best way to troubleshoot.
Thanks.

Best way to troubleshoot an FIP is with a nanocom. Has to be the P38 diesel version system, V8 nanocom won’t do. Don’t bother with Hawkeye they aren’t suitable for P38. Keep in mind the price of a nanocom is similar to price of a new pump, so best bet is to coax someone that already has one/knows how to use it - do not underestimate the bargaining power of custard creams

Datatek · Oct 17, 2023

Grrrrrr said:
Static timing is set using a dial guage as per RAVE. After that it is a specialist job if the FIP itself is acting up. You can get a refurbed pump from Diesel Jones in Manchester but at £650 you want to make sure it really is that.

Is the coolant pressurising at all? You can make an adapter for the glow-plug holes and use an airline or a bike pump to pressurise each cylinder with the valves shut (take the cam cover off so you can check both inlet and exhaust ate shut) and see if any coolant pushes out. If it does then either head gasket or more likely cracked head. If no issues then back to FIP.

There is an easier and more accurate way to do the static FIP timing than using a dial gauge.

Grrrrrr · Oct 17, 2023

Datatek said:
There is an easier and more accurate way to do the static FIP timing than using a dial gauge.

Done it but I think I would follow the manual when troubleshooting to make sure everything is factory spec. The part everyone forgets is the shim under the cam locking tool on higher mileage engines because it is in a different section from the FIP timing. I'm sure it makes a difference.

brianp38dse · Oct 17, 2023

Hummmm Custard creams

P38 2.5 Diesel - running issues

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