THP 155 Engine Hesitation

[Gazski66]

Good luck Chris, keep us updated please

[Jonbays]

There is a thread on the problem and work done on my car here.

http://www.ds3club.co.uk/showthread....r-acceleration

Hi Jonbays, I haven't had it on a diagnostic yet. Going to try and speak with my dealer this afternoon see if I can get them to look at it.

I can see yours is a THP 155 - was this the same car that you had this work done to?

[Chris_Blue]

Good luck Chris

[FLP]

I had the same problem 2 times this week! Mine is also a 155 :-s The first time I didn't believe it. I thought it was my imagination again, as I'm always looking out for hesitations (always keeping the well known problems with the THP's in mind). But yesterday, it happened again. Both times I was giving it the beans going uphill. Both times it was in 4th or 5th gear (I'm not sure). Suddenly the car stops accelerating for about a second, and shudders, and then it goes on with what it's supposed to do..
I checked the oil level afterwards, and noticed it was low on oil. Don't know if that could have been the cause, but it sounds unlikely to me..
I have to bring it in for it's first service in 2 weeks time, so I will do some more test drives next week to make sure, and mention it when I bring it it. I'm curious to see if they mention any of the known problems (that officially don't exist it seems..)

[Chris]

Hi FLP - the problem you've described sounds identical to mine.

My oil was on maximum after having a recent oil change, so I'm not sure that would have anything to do with it.

I too put it down to my imagination/paranoia the first time, but after half a dozen times I was sure there's a problem! They will probably tell you your car just needs a service... but mine had one less than 3k miles ago so don't let them fool you.

Anyway, just had a call from the dealer to say that the car needed a 'software update' and that it now drives fine! I'll be interested to see if they managed to make the car hesitate for them beforehand, for them to now say its fine?? I don't believe it, however. But we'll see.

[Chris_Blue]

Ask them to comment on whether it could be carbonised inlet valves Chris, with the deposits getting in to the combustion chamber
Or even a High pressure fuel pump issues

[Superfly Guy]

Ask them to comment on whether it could be carbonised inlet valves Chris, with the deposits getting in to the combustion chamber
Or even a High pressure fuel pump issues

I suspect the dealer knows exactly what the issue is.

[Jonbays]

I think we all know where this is going. The dealer is not likely to be being truthful here and a little Q&A session with him preferably in writing will be quite instructive.
Ask what problems or fault codes were identified and how?
Why the car needed a software update and how this would fix the faults identified?
What faults were found with the old software?
What version software was it and what version is it now and what changes were made in the new software for what reasons?

The answers are sure to be cringe worthy BS if you get any in writing.

The honest answer will be "don't know' but you will probably get something like "we couldn't find any problem so we updated the software and its all fine now" The honest answer from the mechanic would be "reset fault codes found test drive OK"

[Chris]

I actually took with me an info rapid I found on here, regarding hesitation due to the carbonisation of the inlets, which surprised them! However when I collected the car I was shown that the engine code was different, which I could have told them as it was an old info rapid from a THP150.

All I suspect they did was give it a good thrashing/blow out? Engine was still notably warm when I collected some two hours after they called to say that it was ready...

Just waiting now until it happens again, as I'm 99% sure it wouldn't have been cured. At least I'm following their procedures and if anything goes bang, they have it on record...

[Chris_Blue]

You never know- i had a little noise from the engine that didnt sound great.
Dealer said have the service and oil change and it should deal with it- 2 weeks later noise has not reappeared (Fingers crossed)
You just never know

[Toxic]

If BMW have I identified the problems with carbonisation on the inlet ports and are starting to do walnut shell blasting, perhaps were should all start asking the dealerships to carry this out.

Another way to get this highlighted to Citroen is to raise the issue with BBC watchdog. If enough people here raise the same issue then they can push on our behalf for Citroen to acknowledge the fact there is an issue and get dealing with it.

[Chris_Blue]

Am sure everyone realises that all GDI engines, whatever the manufacturer, gets carbonised inlet valves at some stage
Think the trick is to minimise the problem by using quality fuel, adjusted driving style, catch can, fuel additive periodically, and basically react as soon as a fault comes along
I wouldnt be bothered with a walnut blast through every 30.000 for instance. Bet its like driving a new car.

[cyclone]

Am sure everyone realises that all GDI engines, whatever the manufacturer, gets carbonised inlet valves at some stage
Think the trick is to minimise the problem by using quality fuel, adjusted driving style, catch can, fuel additive periodically, and basically react as soon as a fault comes along
I wouldnt be bothered with a walnut blast through every 30.000 for instance. Bet its like driving a new car.

While all those things will be good for the car the only one that will help the valves is the catch can. Toyota is using a secondary port injector to solve the problem and Audi is going to a similar system; they introduced it at the North American International Auto Show in Detroit earlier this year.

[Toxic]

The only thing that would help is to vent to air. Even a catch can will allow oil vapour onto the ports and inlet valves. They will still carbonise but at a slower rate.

[cyclone]

We never claimed a magic cure mate but you can only try to do what you can to mitigate it. You know that's not environmentally sound plus it's messy leaves an oil film all over your engine. Those just my personal views feel free.