THP 155 power loss, rough idle

[trotters]

Hi all

I have a 2013 THP 155 with 26k miles on the clock. I’ve only had the car 2 months and have hit a number of issues.

I’ve always found the car feels a bit jolty when driving slowly (under 10 mph), and it seems to get worse the longer I’m stuck in traffic. I got stuck in a traffic jam for about 45 minutes the other day and could feel the car shaking when idle after a while (there seemed to be a bigger shake about once a second). It also felt like it was close to stalling a couple of times when pulling away. Once I finally got out the traffic I noticed a lot of the power was gone. Acceleration feels smooth (aside from when driving slowly it), but there is a distinct lack of power (and fun ) almost like the turbo isn’t working. I’ve not seen any errors when starting the car and don't have a OBD reader, but something is clearly amiss.

I’ve also found that if I’m in first and I just let the car slow down (take my foot off all pedals), it will not move smoothly and to move away I have to use a feather touch or it will jolt. Is that normal? None of the other cars I’ve owned have had a problem with doing that. As someone who lives in London I often need to do the car’s minimum speed.

I’ve read a whole bunch of forum posts on here and have found a number of possible causes of my issues. The car is just out of manufacturer’s warranty, but I’ve got a non-Citroen warranty from the garage I bought it from (Foster & Heanes). I’m due to take the car in on Monday and they are clearly very keen to sort all the issues out. They aren’t a Citroen garage, so whilst I trust that they know what they’re doing in general, I think they might miss some of the many quirks these cars seem to have.

I’m planning to ask them to check the following for problems based on what I’ve read:
• Carbon build up on inlet valves
• High pressure fuel pump issues
• timing chain + tensioner

Can anyone suggest anything I've missed that might help them fix it? I love the car when it works!

[lfcrule1972]

Sorry to hear this, the original 150 THPs had the issues you've listed above so they're a good place to start. I think we'd all hoped that the problems were less common on the 155 THPs, perhaps that was just cause they needed a few years to start showing ?

Hope you get this resolved quickly, don't forget to post back when it's been diagnosed - good luck !

[Superfly Guy]

As above and yes a great place to start, 26k will mean noticeable carbon build up on the valves and unless it has been replaced, the HPFP will almost certainly be capable of causing the idle/slow speed issues you describe. i had mine replaced with the latest revision.

[trotters]

Took it for another drive today. This time I was able to stay between 40-60 for a good 10 minutes and my power gradually came back. Very odd :confused:

Will see what they say on Monday anyway

[trotters]

So, the garage took the car for a 45 minute drive through as slow traffic as they could find. They said the car is a bit jolty in first but they didn't think it was much different to other similar cars. I've not owned any similar cars so I can't judge. 0 error codes logged and they said they didn't know where they would start to fix it. I did have a faulty heater fan (stuck on full blast) so it is possible that I was driving it an an unusual way.

Think I may take it for a walnut blast and see how that goes! Shame Jamie is 2 hours drive away

[Superfly Guy]

Think I may take it for a walnut blast and see how that goes! Shame Jamie is 2 hours drive away

Yes its a four hour trip plus the time you are there so maybe a day written off, then again you could take it elsewhere, pay a fortune and still lose the car for a day (minimum).

[trotters]

I don't think I'd risk going somewhere else considering about 50% of posts end up suggesting SPTuning here

So yea, at some point I think that will have to happen.

[Jamie@SPTuning]

THP 155 power loss, rough idle

Your welcome here anytime. I'm sure there should be someone reputable in your area that can handle the work required...any mini specialist maybe?

[lfcrule1972]

I don't think I'd risk going somewhere else considering about 50% of posts end up suggesting SPTuning here

So yea, at some point I think that will have to happen.

Only 50% ???

[trotters]

Thanks Jamie. I'll look around

If it ever gets to that... at the moment the car is a mess. The longer I get stuck in traffic, the more rough my idle becomes and I lose power. If I park up after traffic, the car will still be a mess the next time I drive it. However, if I drive it down the motorway at a sustained 70+ mph my power will gradually return.

I got stuck in traffic for 2 hours the other day and the car started running so rough I could feel the seats shaking. The car becomes quite unpleasnt to drive; very jolty . Something tells me this is more than just 26k worth of carbon build up. I also noticed my coolant has dropped from max to below minimum in 2 months.

I spoke to a guy who runs a Citroen garage and he said I should try to get the non-Citroen garage to pay for Citroen to update the car's software and do some diagnostics. Will see what they think about that, otherwise I may have to return the car

[trotters]

A little update. The garage spoke to a "master engineer" at Citroen and they said there is an outstanding recall on the car.