FR TDi - Hesitation (2500rpm) / Boost Cut?

[Nick G]

I don't know what could be causing this, but it's only done it randomly a few times so just wanted to know if anyone else has experienced it?

I don't want to take it to a dealer as i know if the computer doesn't show up a fault they'll not be interested in it....

What happens (happened) is around 2,500 rpm the car feels like it's got a flat spot and almost boosts then stops again then goes again.... It's like it's hesitating / Under-fuelling or something to me (Going back to my old Renault 5 days)!!

Anyone else experienced anything??

Car is a 2008 Leon FR TDi 170 by the way, 18k miles.

 

[WeeG]

My guess mate MAF Mass Airflow Meter, tell tale signs you have

 

[Nick G]

My guess mate MAF Mass Airflow Meter, tell tale signs you have

I hoped it wouldn't be that :-( I've had it on various cars but it's always seemed to be one of those Undetectable faults, usually meaning it's really hard to get replaced under warranty??

Any chance it would throw up a fault code on the Leon's or is it unlikely?

 

[WeeG]

It could do mate, the best way to find out is to disconnect it and try drivin it for a minute. It sometimes doesn't throw it up. To be honest your car is pretty new and low miles for a MAF fail but could be Hope this helps bud

 

[Willie]

This could be your TCS/ESP or the like kicking in cutting your boost

On the MK1 Leon this can cut in without the light on the dash coming on and has the same sort of symptoms.

Does it only do it when your accelerating hard?

 

[Tam]

does it idle at 1,000 rpm at the same time too?

 

[nc30rider]

Sounds like a regen to me, if so perfectly normal behaviour

 

[AndrewJB]

First of all it sounded like the stutter im experiencing aswell



But yeh it could be your DPF Regen,I know mine isnt doing it as it isnt there

 

[wjohnson]

Yeh sounds like a regen. I really don't like regen mode. God knows what it looks like from an outsiders point of view but mine stutters and splutters like some dodgy old citroen diesel with 300,000 miles on the clock . Really think the technology is not ready for the road yet.

 

[/dev/null]

Or it might be the same as what mine does - I had the MAF replaced and still no luck. Although unplugging the MAF fixes the problem! It doesn't idle at 1k though so I don't think it's a regen. Someone on here mentioned the EGR valve.

 

[SeanCorky]

My car has been stuttering over the last few days, it's not doing a DPF Regen and it's not at a specific amount of revs

Its annoying, before i was going 40 in 4th doing about 1500revs and every 5-10 seconds it would chug as if i had dropped then pressed the throttle in a bit

 

[SeanCorky]

My car has been stuttering over the last few days, it's not doing a DPF Regen and it's not at a specific amount of revs

Its annoying, before i was going 40 in 4th doing about 1500revs and every 5-10 seconds it would chug as if i had dropped then pressed the throttle in a bit

I've decided, it's when the engine is cold around 1500revs. Its pissing me off!

 

[AndrewJB]

Any Error codes?

 

[SeanCorky]

Any Error codes?

Nope, scanned this morning and just the usual interior sensor code

This will be another unsolved mystery then

 

[n_d_fox]

I've noticed something similar on mine... 59 plate FR tdi with under 7k miles on it.

I first noticed it when i went over a hump back bridge near me, as the car crested the bridge and started down the other side the car would hesitate as though i had let off the accelerator. i definitely hadnt. i have been over the same bridge a number of times and it does it every time without fail.

I noticed it again this morning, going over another bridge but no where near as steep.

I wondered if it was the fuel moving in the tank and there being a momentary loss in fuel pressure, the only contradiction to this is that the tank is near enough full at the moment so that wouldnt explain it for this mornings occurance.

I have noticed that the revs are holding at 1K a few times though but am not getting a DPF light on the dash and i thought the CR engine was better suited to the whole DPF filter thing !? plus, i havent even done 7K miles yet !

 

[AndrewJB]

The 1k Holding sounds like yours is Regening,You wont get a light for Regeneration unless it goes wrong and even tho the CR is better at doing it! it still needs to do it!

 

[robin cur]

Mine didn't seem right last night seemed like it was try to pull back all the time, and was not runninig very smooth took it for a long run and gave it some welly and today seems to be running ok think it was doing regen but I now sure how I would know.

 

[shaw25]

My 06 fr tdi has being doing this for a while too but yestarday morning was really bad and then eml came on so took it to a mates garage scanned it and egr fault came up.

 

[SeanCorky]

Done a bit of town driving today, it's not only when the engine is cold, it's just every now and then around 1500revs

 

[shaw25]

Put the car in for 60 000 mile service today and the problem seems to have gone. The fuel filter was cloged with oil, so can anyone tell me how oil has got into my fuel filter?