Random Revving!

[bigbluec 0]

Hi guys my valver has started to rev erratically when i let off the accelerator and even once i've come to a standstill i have done a quick search on my problem and read that it could be the isv but i have cleaned it up and it is buzzing nicely so what else could it be? please help!

[Henny 0]

is yours a 1.8 or a 2litre 16v?

 

Welcome to the forum by the way... :)

[bigbluec 0]

Thanks Henny its 1.8 16v and not sure if this is connected but the rev counter is also playing up cutting in and out and giving odd readings even when accelerating smoothly

[Henny 0]

ah-ha! 1.8? I may be able to help then! :wink:

 

It sounds to me like there is a missing/dodgy earth strap that may well be the cause of both of your problems... 8)

 

There's a THICK earth strap (the one that's got the battery terminal on it!) which goes from the battery to the chassis (on the battery tray) and then onto one of the gearbox to engine bolts. These have a nasty habbit of going green and high resistance which doesn't help any of the engine sensors much. There's also one from the corner of the head to one of the bolts that holds the coil on. AFAIK, these are both common to all 4cylinder 'rados and cause no end of problems! :roll:

 

Try replacing both of these, shouldn't cost much from the dealer (about £25 for both IIRC) and see if it cures your problem.

 

If it doesn't, then take the big rubber bit off the top of the metering head, and check that it's nice and clean in there, if it's really oily in there, or there's any solid debris at all, you need to clean it out VERY CAREFULLY! If the flap becomes contaminated too much, then the weight of it becomes altered so the way it reacts to changes in air movement will alter causing all sorts of headaches (yes, I've had this happen to both of my K-Jet cars! :roll: ).

 

If neither of these cure it, then it could well be the good old ignition switch playing up... Again, about £25 and an hour to fit (if you can use a screw driver, you can DIY! 8) )

 

Good luck!

[Riki 0]

Might be worth looking at the throttle body switches. If the cable is adjusted up too much or sticking when you let off the throttle it may not be hitting the idle switch. Also make sure that the multi plug going to them is attached. The heat from the exhaust makes them brittle and they sometimes break.

 

Hope this helps.

[bigbluec 0]

Hi guys thanks for your thoughts sorry it's taken so long to reply but taken me this long to get logged back on forum obviously doesn't work with aol! anyways have tried 2 of above but no joy havent bought the ignition unit yet as i'm broke thanks to my lovely C! any other ideas before i cough up for the ignition? also noticed that it has started to go a bit haywire revving wise on cold starts so could this all be down to a dodgy auto choke? :cry:

[big_mac 0]

my g60 has had similar problems, revving during gear changes, sitting at 1500-2k revs on tickover etc.

 

i got the fault diagosed as a faulty throttle position sensor, just needed adjustment only £25 squid and an hors work, pity the garage that did it left the bost pipe to the throttle body hanging off.

[Rossco 0]

ah-ha! 1.8? I may be able to help then! :wink:

 

 

There's a THICK earth strap (the one that's got the battery terminal on it!) which goes from the battery to the chassis (on the battery tray) and then onto one of the gearbox to engine bolts.

 

Try replacing both of these, shouldn't cost much from the dealer (about £25 for both IIRC) and see if it cures your problem.

 

 

Any chance someone can chuck up a pic of the aforementioned earth strap, this may sound weird but i dont think my cars got one!!

[CazzaVR 0]

Check all the hoses too. My 2.0 16v started to do this, and I traced it to a split rubber pipe coming off the ISV. Got a new hose for a couple of quid- cured!

[shane k 0]

Dont know if ure still having the problem but i just recently had the problem on my 2.0 16v, checked all the above but nothing, therefore i took it to Awesome Gti - they ran a diagnostic check and noticed that the fuel filter was faulty............they fitted a new one in and hey presto !!............idle's sweet now !!!