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Full Version: Misfiring at 2.5k
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Hi all, 

Long time no see, hope you're all doing well!

I recently pulled my trusty 306 HDi out of storage to use as a daily once again.
However, I'm having a few issues a wondered if anyone could offer any advice.

Apologies if this is covered in another thread, I did have a look but nothing seemed to be quite the same.

The car refuses to rev past ~2.5k if you try it misfires and runs like crap for a few seconds and then goes back to normal.
When I first pulled the car out of the garage I had 3 stored codes (P0120, P0220) - Which was caused by me putting a 406 coupe TPS on when i was in a pinch. - I have swapped this out and returned wiring to how it should be and these faults are now gone.

I also had another code (P0230). I changed the fuel pump to an R70 and also threw on a brand new Bosch FPS.
After changing the FPS the car seemed to rev higher, all the way to the fuel cut and it seemed the issue was resolved.
I have cleared all codes and none of them have come back. 

However within a few days the issue has now returned, but no fault code is logged.

I'm about to start troubleshooting with different sensors and the wiring loom, I just wondered if anyone had any pointers that might help me?

Any help is greatly appreciated, thanks in advance!!
Just for reference video below:

Car is idling fine, and responsive to revs.
I go for full throttle - As soon as it hits 2.5k rpm - begins misfiring and running rough and cuts out (it doesn't always cut out, it sometimes catches itself - runs rough for a few seconds and then becomes responsive again)
I try and restart the car and as you can hear it almost sounds like it has no compression but then does fire into life running rough for a few seconds and then begins running normally again.


https://youtu.be/Zphr4ltP8BQ
how long has it been in storage for, have you tryed putting a new a fuel filter in as diesel gums up parts so it may just need to run.
(10-03-2019, 06:01 PM)madmadmax Wrote: [ -> ]how long has it been in storage for, have you tryed putting a new a fuel filter in as diesel gums up parts so it may just need to run.

It was in storage for around 3 years, I have the stuff to service it but I haven't yet.
I did think fuel filter, however I remember something similar happening before it went into storage when it was serviced regularly.
That's one of the reasons I changed the pump. It could just be that the intermittent nature has thrown me off and it will certainly need doing anyway!

I will get it serviced and see how it goes.
Lifters collapsing, what state is the oil in?
(11-03-2019, 12:51 PM)Ruan Wrote: [ -> ]Lifters collapsing, what state is the oil in?

The oil is old currently, the car isn't being used - I was planning on servicing in the next few days.

This behaviour was occurring before its storage period.

Not good, If that is the case Sad
kind of like limp mode?
(12-03-2019, 05:24 PM)Magenta Sunset Wrote: [ -> ]kind of like limp mode?


Well, kinda but i get no codes, no management light.
Its more like a 'misfire' in that it idles really lumpy and if i let it cut out it doesn't want to start.
Until its done a few cranks then it runs fine again (up to 2.5k)

I hope its not a mechanical failure but more and more point to it.
So, I serviced the car tonight fresh oil & filter, fresh fuel filter & fresh air filter.
I also pulled the wiring harness from the engine bay to check for faulty wiring as well as cleaning connectors. 

There was some damage to one of the wires going to the high pressure rail sensor which I repaired.

Significantly, I noticed if I don't wait for the car to warm up before trying to rev it, it will rev well past 2.5k up to past 4k rpm.
However, if I leave it running to warm up and try to rev it the issue will eventually present itself, occurring at 3k and then eventually settling at just under 2.5k.

If you gradually bring the revs up and then let off as soon as it starts to run crap it will return to normal almost immediately.
However if you go full throttle it will generally not catch itself, white smoke out the exhaust and splutter out.

TLDR:
Car will rev past 2.5k and act normally until its been running for a few minutes.
The 'misfire'/poor running will begin to creep in, eventually not allowing it to exceed engine speeds of just under 2.5k.
Again, no fault codes.
I'd hazard a guess at a dead turbo, sounds like it's flooding the cylinders a bit, or perhaps a dodgy injector. Needs more investigating, is your exhaust oily? When it white smokes, does it stink of unburnt diesel or not? Try a leak-off test and see what turns up.
(14-03-2019, 10:07 AM)Poodle Wrote: [ -> ]I'd hazard a guess at a dead turbo, sounds like it's flooding the cylinders a bit, or perhaps a dodgy injector. Needs more investigating, is your exhaust oily? When it white smokes, does it stink of unburnt diesel or not? Try a leak-off test and see what turns up.

Exhaust isn't oily at all, it would make sense that an injector is flooding a cylinder, I'll do a leak off test and hopefully that shows me the culprit!

Thanks for the advice!
if it does turn out to be worst case, i have a full engine from a 2000 hdi i bought it for the gearbox for my ph2 i still have the engine and it has got everything on it still injectors pump turbo ect ect. im ner newark if you need it, send me a PM £80 i just need it out the way.
(14-03-2019, 07:39 PM)jamie182 Wrote: [ -> ]if it does turn out to be worst case, i have a full engine from a 2000 hdi i bought it for the gearbox for my ph2 i still have the engine and it has got everything on it still injectors pump turbo ect ect. im ner newark if you need it, send me a PM £80 i just need it out the way.

You dont happen to have this on ebay do you? 

Because I literally just paid for one last night. £80 from Newark which is really close to me.

Is your username something about BMW's ?
I had a similar problem on a Ford diesel a few years back and it turned out to be air being sucked into the fuel lines through a perished seal. It would run fine 80% of the time and then it would feel like it was running on only three cylinders, sometimes it would clear in minutes and other times it could last a couple of days.
These run pressurised fuel systems, they don't draw air.
So does the Ford but at some point it has to be sucked out of the tank as that isn't pressurised.
306 HDi's have an in-tank lift pump so the whole system is pressurised.
This isn't electronic issues, note that there's no compression after it cuts out, this is a mechanical issue.
Oh I completely missed the post with the video, lifters it is lol. xD