P38 2.5 dhse - strange starting issue only every 3 starts

Grrrrrr said:

If you have MAF fitted then ignore the air temp as that will be a default value

That water temperature looks odd though.

Can you get it up to normal operating temperature (needle at 12 o'clock) and then record a trace onto an SD card?

I'll dig out my PC and try to find an old trace of mine (it'll be on this forum somewhere) although mine's pre-EGR and MAF so won't be exactly the same.

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Jamieae said:

Datatek - the battery came with a sticker on it stating not to charge so I didn’t charge it before fitting. I purchased it from battery mega store as suggested in other threads/posts. Should I try charging it or possibly contact battery mega store and see what they say.

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Jamieae said:

Hi guys. I have just joined the forum, hoping for some help. I have searched forums and online and gathered lots of information but my problem still persists. Here’s a brief rundown.

it’s a 2000 p38 2.5dhse (m51 bmw diesel engine)

The scenario is i go start it and the glow plug light comes on and then after 10-15secs goes out, I’ll then crank the engine and it’ll start fine but have a high idle (around 2000rpm I’d guess) and the rev counter won’t work.

I will then turn it off and go to start it again and the glow plug light won’t come on and it’ll start as normal (normal idle and rev counter working) but will have a gearbox fault message on the dash.

I then turn it off and start again (with no glow plug light on dash again) and it’ll start, idle and rev counter all ok and without the gbox fault.

I can then drive it like normal but when I go to start it again it’ll do the some thing as before. High idle first start, normal idle gbox warning second start, all good third start.

before I get told off and to search I have checked and or replaced the following

- Crank sensor x 2 (one new one and one tested used one, just incase the new one was faulty out the box)
- in tank fuel pump
- glow plugs (Bosch ones)
- glow plug relay - genuine tested used one
- maf sensor - gen. tested used
- map sensor - gen. tested used
- all vacuum lines replaced
- all boost hoses replaced
- ecu coolant temp sensor (green one on head)
- new Bosch battery
- injector leak off pipes

I’ve checked the following

- 150ml ish of fuel delivered to the high pressure fuel pump in 15seconds (only when glow plug light comes on is this correct)
- 12volts at all the glow plugs when glow plug light comes on dash
- alternator gives 13.7volts when engine is running
- cleaned and checked all plugs going to sensors, high pressure pump, etc checked for broken wires/insulation etc.


there’s probably more that I’ve forgotten but you can see I’ve had a go at the usual suspects but the problem is unchanged.

the only thing of note I can think of is that it has an end tuning chip fitted to the ecu. This was fitted well before this issue started.

if anyone has had this issue before or knows of someone that could have a look at it locally (Hampshire/Wiltshire based) and help/ideas will be much appreciated.

I’m getting close to plugging the plug on it so on another note if anyone wants a 3 owner 138k p38 with the above issue please get in touch as unfortunately think the only way forward would be to break it for parts which would be a shame but can’t see someone wanting to buy it as it is.

once again any help would be much appreciated.

many thanks Jamie

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Gearboxman said:

Hi Jamie,
I was searching online and noticed your post regarding the experience with the P38 dse and I have almost identical symptoms with the revs and tachometer not working.
Sometimes it start normal and everything is working and sometimes( randomly) it revs up crazy and no tachometer working. When it happens also the glow symbol goes on a few seconds.
I have also a modified engine ecu with sockets for the 2 eproms .
I will open the ecu and check them first!
Cheers Marco

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