Leon FR 150- Reving After Let off

[M6ccy69]

Hi all, Sorry if that doesn`t make sense. After reving the car through the rev range, when u let off the accelerator specially when high in the revs, its revs it self. Its like somethings stuck. You guys know what i mean? Does this happen to anyone else. I drove my mates 56 plate ibiza fr today & that doesn`t do it & its the same engine.

 

[daveyonthemove]

Not had it happen in mine. Not sure what to suggest to diagnose it either.
Any access to vagcom?

 

[M6ccy69]

gutted! thought it might of been normal. access to vagcom?

 

[daveyonthemove]

Not normal if mine is anything to go off.
Do you know of anyone with vagcom, or have you asked on the forum for help in your area?
Wasn't it mapped recently? do a search to see if anyone with a map from the same company has had similair problems.

 

[M6ccy69]

i could ask, yeah its recently been mapped but this was from day 1 when it was bought new. i just thought it was normal, but now i`m not to sure.

 

[Viking]

Does it burn much oil?

 

[Nath.]

sticky gas pedal ??

 

[daveyonthemove]

Thats interesting.
If it had a fault then i would expect it to have been picked up when the remap company did a scan prior to putting the map on.
I'd be surprised if the fault was a sticky throttle as it's drive by wire. I'm not 100% sure, but i don't think are electronic, not cable controlled? I could be wrong.

 

[M6ccy69]

doesn`t burn no oil, not sure about sticky pedal. i`m not sure, might give seat a ring. just spoke to a guy i know who`s on the forum to, he said his does the same! going from 1st to 2nd like mine does.

 

[Danny_FR]

I've done some more looking in to this after you text me and it looks I was right. When you boot it and take it right up to the limiter, the fuel pump is running at full pelt and the fuel lines are under pressure. It takes a fraction of a second for the pressure to drop when you release the throttle, hence why it hangs on to the revs. I phoned the chap who remaped mine (diesel specialist) and the father in law (lorry diesel engine mechanic) who both confirmed what I thought.

Mine did it from standard too but never bothered me. It only does it from 1st in to second gear because sometimes I don't quite catch it before it hits the limiter. It does give you one hell of a power surge that nothing can keep up with lol!

 

[M6ccy69]

I've done some more looking in to this after you text me and it looks I was right. When you boot it and take it right up to the limiter, the fuel pump is running at full pelt and the fuel lines are under pressure. It takes a fraction of a second for the pressure to drop when you release the throttle, hence why it hangs on to the revs. I phoned the chap who remaped mine (diesel specialist) and the father in law (lorry diesel engine mechanic) who both confirmed what I thought.

Mine did it from standard too but never bothered me. It only does it from 1st in to second gear because sometimes I don't quite catch it before it hits the limiter. It does give you one hell of a power surge that nothing can keep up with lol!

lol!! i know what u mean, if u time it right hell its off! ha. Yeah what u say is spot on!

 

[slick]

Yeah, i find mine does take a sec to recover from very high revs... i think its due to the above reason of fuel pump.. dont often red line like that, drive around on the torque and not the revs mostly...

 

[devonutopia]

I had a couple of moments similar whilst thrashing up and down a Czech abandoned runway. Trying to shift at 4500rpm, dip clutch, off throttle, but revs stuck around 4000 and didn't dip. It was almost as if it was over-running a bit - almost felt like clutch slip, although that has since been ruled out. I wondered if it was DMF issue perhaps, but it never repeated itself. It only did it under extreme hard driving, and the car was red hot. I saw sump oil temps of 110 degC - Usually around 75 for normal driving....

Car did not burn any oil either, and returned to normal on my return to the UK (Czech diesel is a bit crap to be honest....)

 

[Scamps]

Mine does the same to 1st to 2nd gear, always has. I don't mean to over rev it, but it sometimes catches me out, hits the limiter and holds onto the revs for a second or so before dropping.

 

[M6ccy69]

Mine does the same to 1st to 2nd gear, always has. I don't mean to over rev it, but it sometimes catches me out, hits the limiter and holds onto the revs for a second or so before dropping.

yeah buzzin! sounds like mine. I`m glad its just not me! thanks for the reply.

 

[micky 32]

It's normal, mine does it if i rev it to the redline and change gear. Takes a few secs to drop.

 

[muddyboots]

Not sure I believe the fuel pump theory though.

The PD pump injectors are are driven once per revolution off the cam, they'll generate the same pressure whether at idle or redline because that's determined by the cam profile; the difference in fuelling is determined by how long & when the injectors open, which is done electronically.

 

[M6ccy69]

thanks guys for all the reply`s.

 

[FAST AL]

Said it before but use the dielectric grease treatment on your maf.It pays in the long run I beleive, and my cupra tdi 150 has a slight rev on some gear changes but so what if they go like stink anyway.

 

[neo265]

Any chance this is caused by the momentum of a heavy flywheel?

I wounldnt of thought so because of the high compression of diesels, but it could be. Does it on mine too btw.