P38A Cold start / hot start

plumbfisher · Apr 11, 2019

'Morning All,
2001 DT.
(When glow plugs are all working!) it starts 'on the button' from cold,
but once its warmed up it always takes a bit more turning over before it fires up.
Maybe twice as much as when cold.
I've got a good strong battery and it is reliable and it always starts, so its n

ot really a problem,

Question is - why is this?
I've read before about 'hot start fix'. What does this do, and why?
Questions, questions...

wammers · Apr 11, 2019

plumbfisher said:
'Morning All,
2001 DT.
(When glow plugs are all working!) it starts 'on the button' from cold,
but once its warmed up it always takes a bit more turning over before it fires up.
Maybe twice as much as when cold.
I've got a good strong battery and it is reliable and it always starts, so its n

ot really a problem,
Question is - why is this?
I've read before about 'hot start fix'. What does this do, and why?
Questions, questions...

On your year of car that should not be a problem. Check that the lift pump is working.

plumbfisher · Apr 11, 2019

Is that the 'in tank' pump? Yup, that's working. If it wasn't ,would that not affect cold starting too?
Spill off pipes all fine too...
I was just interested to know why

wammers · Apr 11, 2019

plumbfisher said:
Is that the 'in tank' pump? Yup, that's working. If it wasn't ,would that not affect cold starting too?
Spill off pipes all fine too...
I was just interested to know why

Not generally, if the fuel level is high. More fuel is injected for cold starts than is injected for hot starts. On your vehicle lift pump is active when cranking, this was introduced to try to cure the hot start problem. Diag to check timing modulation would be helpful. The chains maybe stretched and the static timing retarded.

Datatek · Apr 11, 2019

plumbfisher said:
'Morning All,
2001 DT.
(When glow plugs are all working!) it starts 'on the button' from cold,
but once its warmed up it always takes a bit more turning over before it fires up.
Maybe twice as much as when cold.
I've got a good strong battery and it is reliable and it always starts, so its n

ot really a problem,
Question is - why is this?
I've read before about 'hot start fix'. What does this do, and why?
Questions, questions...

I have 2 P38's, a late 99 and a late 00, on one the injection modulation is 58%, it starts fine hot or cold, on the other it's way off at 76%, it starts fine cold but takes a bit of cranking when hot if left for more than 10 minutes or so. I assume from that, and from what I have read on here, that the modulation being way off is the cause of the problem, so timing chains stretched and the FIP in need of re-timing and/or chains replacing.
The hot start fix fools the EDC into thinking the engine is cold putting the glow plugs on and richening up the mixture.

plumbfisher · Apr 11, 2019

I think that explains it, I doubt the chains have been done since new. Otherwise it runs fine so I can live with it for now.
Thanks for your help.

P38A Cold start / hot start

plumbfisher

Active Member

wammers

No longer with us, RIP

plumbfisher

Active Member

wammers

No longer with us, RIP

Datatek

Well-Known Member

plumbfisher

Active Member

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