[vivih]

Hi everyone, please bear with me...this is my first post.

My 2012 CRDi blue drive active has taken to bunny hopping when temperatures get to around 18°C (& above).
It starts up ok in all weathers and doesn't do this in cold/cool weather, just when the mercury starts to rise.
There's no particular speed at which it gets worse/better, and causes a bit of drag on the acceleration/drive, but then seems to settle down after a few minutes (maybe 5?)
It's as if fuel is struggling to get through, but I can't understand this as I thought fuel got thinner in warmer weather and therefore flows easier (please correct me if I'm wrong...and if this is indeed the problem I have 🙈).
It's frustrating, but also concerning as I work 15 miles from home, travelling on one the regions busiest motorways.

Has this happened to anyone else, or can anyone shed some light on what it might be?

Thanks

[The Gonz]

Hi, Vivih, fine for a first post - Welcome!

I can't speak directly to the problem but don't take temperature thinning your fuel as a relevant assumption. By the time you factor what the sensors in the system are doing, you may end up with the opposite effect, as occurs with building air conditioning systems overcompensating.

Any chance your aircon or engine radiator fan is cutting in when it happens? We just need to pin down all the symptoms.

[vivih]

Thanks, that's a fair comment about the thinning, and not one I'd thought of (obviously 🤦🏻‍♀️).
As for the fan - I've not heard it kick in and my dashboard temp reading is always within limits, so maybe I can rule that bit out?.
The air con needs regassing - has done for at least a couple of years 🙈 - and I've put it off as I've been told it's the dearer type it needs (tbh, I've forgotten which type it is, it's been that long). I've not pursued it as I don't mind cracking the windows open instead of using that, but if it would help with the bunny hopping, maybe I should think about getting it done? (Let's be honest here, it not looking like I'll need to do it due to the weather, anytime soon, is it?!? 😄)

[The Gonz]

Regassing your aircon won't help your problem. I was just looking for a correlation.
Have you used a code reader to see if some fault condition has been reported by the ECU?
I'm guessing not by your question. An On Board Diagnostic (OBD) bluetooth reader is cheap and easy to use.

[Lorian]

When was the last time the Diesel fuel filter was serviced?

[eye30]

Have you had fuel pump tested to make sure pressure ok

[vivih]

Regassing your aircon won't help your problem. I was just looking for a correlation.
Have you used a code reader to see if some fault condition has been reported by the ECU?
I'm guessing not by your question. An On Board Diagnostic (OBD) bluetooth reader is cheap and easy to use.

Have a simple code reader I used...no codes came up

[vivih]

When was the last time the Diesel fuel filter was serviced?

I'll be honest...I can't remember: it may have been last year, it may have been last decade! (Bad memory & the mechanic I use doesn't always give me paperwork).

I'll ask him, to make sure, and get it booked in if you think that might help. Thanks

[vivih]

Have you had fuel pump tested to make sure pressure ok

As with my last reply, I actually have no idea (I know ..I'm rubbish at remembering this sort of stuff!), but I'll mention to my mechanic. Thanks for the suggestion

[vivih]

When was the last time the Diesel fuel filter was serviced?

Apparently the filters were all done at the end of last year, and I think he tested the fuel pump, too.

It's still doing it... I'm still stumped!  🤣🤣