Idle revs increasing on FR TDI

[knight85]

as title says,

car usually idles at about 800rpm....but every now and again it seems to creep up to 1k when idling?

It doesnt seem to go back down, however when i turn off the engine it sits back at 800rpm when restarted

Only done this a few times in past week? any cause for concern?

cheers

 

[barker57fr]

mine has done this a few times too, have no clue why either mate

 

[uzi_cupra]

does this happen during warm up? sitting in traffic? random?

 

[T10HJP]

does it make a difference on whether the car is hot/cold? mine seems to jump up sometimes when its cold, but I try not to let it idle for too long (apart from cooldowns after 'spirited' runs )
not really much help, but I thought I'd add my 2pence

Paulie..

 

[Wash It!]

Mine does this also, it randomly appears on hot or cold starts but usually 'clears' after a couple of minutes of driving.

It's not been affecting my cars running or performance or economy so I'm just ignoring it (kinda...)

 

[zach225]

i take it none of you have air con- heating on at the time as this will obviously increase the revs

 

[knight85]

my air-con/ climatronic is always off during summer...thats what windows are for!

only seems to be on cold starts...only has done it twice!...just worried me as you can hear the change

 

[Wash It!]

my air-con/ climatronic is always off during summer...thats what windows are for!

My thoughts exactly!

 

[darkhorse]

Check your battery, I had a similar symptom when my battery was on it's way out

 

[knight85]

cheers will give it a check

 

[uzi_cupra]

does it make a difference on whether the car is hot/cold? mine seems to jump up sometimes when its cold, but I try not to let it idle for too long (apart from cooldowns after 'spirited' runs )
not really much help, but I thought I'd add my 2pence

Paulie..

after your "spirited runs" its better practice to keep driving, maybe for a few mins to let brakes/fluids temps cool rather than sitting on idle as this can cause oil starvation to the head from the high pressures built up after a hard run. also allows oil to circulate in the turbo while the compressor is still spinning

 

[NickCupraR]

When this happens do a little test by, putting you foot under the accelerator pedal and lift it up. Should drop the revs back to 750-800rpm, that is what mine does.

 

[Wash It!]

When this happens do a little test by, putting you foot under the accelerator pedal and lift it up. Should drop the revs back to 750-800rpm, that is what mine does.

Interesting theory, I will try this later when I pop out.

 

[lil3520]

Interesting theory, I will try this later when I pop out.

will try that on mine, next time it happens.

mine tends to happen after alot of town driving on warm days.

 

[mk4 cupra]

i had the same fault on mine when i first got my car but mine has stoped now the only thing i could say was foing it was red x because when i first ever toped up my fuel tank it stunk of red x so i let it use that tank then ever since i filed it back up its been fine.

 

[Jordanwaterhous]

Sure it's not the autochoke? Only happens when engine is cold and does it every now and again, which is when the autochoke is likely to be used.

Idle revs drop to normal after water temp reaches 54 C.

If it is the autochoke (which i highly suspect it is) Then it is completely normal.

 

[Wash It!]

Sure it's not the autochoke? Only happens when engine is cold and does it every now and again, which is when the autochoke is likely to be used.

Idle revs drop to normal after water temp reaches 54 C.

If it is the autochoke (which i highly suspect it is) Then it is completely normal.

Mine never used to do it, now it does 90% of the time.
But as mentioned previously the car isn't seemingly affected by it whatsoever so I'm just happy to let it do it's thing.

@ [email protected] - The pedal-lift didn't do anything! Thanks for the idea though

 

[knight85]

im thinking perhaps battery issues? hasnt done it in about 3 weeks now

 

[NickCupraR]

Mine might be abit different sometimes when I'm driving and I put the brake on and haven't changed down or dipped the clutch quick enough it sticks at 1100rpm then when I lift my foot up underthe accelerator it drops back down. It doesn't affect the car driving ability so not to fussed. Could just be the engine re ing higher to keep it warm if it happens on start up.

 

[James_R]

A little hint: check you actually have a battery charge light, if not the load sensing wire to the alternator is broken and causing the engine to idle higher than usual. The cure is to repair the broken wire, usually under the gearbox.

You'll also get the fault - generator df signal implausible.