Revs slow at dropping
 

When i blip the throttle or come to a junction and dip the clutch the revs seem to take for ever to drop back down to tick over. Any idea's ??

MY99 turbo

Any clue's

Throttle cable too tight ? and or check the small black plastic cover type grommet that sits over the throttle cable. These can become detached and find their way down the throttle cable and get wedged thus causing the throttle to stay open.

I haven't explained this too well but if you have a look at the throttle cable/linkage within the engine bay it should make some sense ?

Another idea or 2

1 Take off the Idle control valve and lubricate with WD40

2 There is 2 multiplugs behind the battery and one under the throttle housing Take them apart and clean them up this will improve the electrical signal to the ECU

Cheers Grant

Cheers for the replys i will try all the options.

Did you get this problem sorted?

If so what did you do????


Mine's doing similar to what you say, dropping slowly to about 1200rpm then down to about 900 finally tickin' over at 850ish.

cheers
eddie

reset the ecu, mine did this when i 1st bought it

an ecu reset sorted it out no problems at all

thanks, i'll give it a try.

p.s. just spent the last hour going through about 70pages of general technical looking for similar faults.

eddie

The reset didn't work.

eddie

Could be throttle position sensor... have idle problem & when CEL lights up the rev needle seems to drop / rise in slow motion

Took the idle control valve off this afternoon, cleaned it and it's made no difference at all.

What i did notice was, the rubber cone/bung which has an eroded appearance has got a slight indentation mark around it, also one area is polished/smooth, could this be the problem?

If so how much do these cost?

something else i did notice on my way home was, going down hill off throttle, more pops quieter than the normal decat pop, is this relevent?

StevieB- No cel light and also no rev rise, now it seems to drop to 1200(which the ecu reset may have cured) normally then slowly to 900.

What symptoms are lambda failure?

cheers

eddie

I still need help :)

Me too !

It will be the Throttle Position Sensor (TPS) I reckon.

The CEL only stays on for a few seconds on mine, so it might be in the history.

It can be checked with a DVM, or select monitor.

Doubt it would be a lambda failure, as you would probably have a bad idle, and bad fuel consumption.

MB

BTW, it will pop more beacause the TPS is probably giving the wrong reading to the ECU, thus still putting a bit of fuel in when you are trying to slow....

MB

Not sure anything is wrong tbh... mine has always been a bit slow dropping the revs, making really quick gear changes a bit painful for the clutch :(.

The reason most cars don't drop straight back to idle is emissions regulations - on lift-off, the ECU keeps a little bit of fuel going through the engine and ignites it as otherwise it could suck through unburnt fuel, which is a no-no for emissions.

Worst case of this I ever drove was a Morgan 4/4 with the Ford Focus 1.6 Zetec engine in it. Sinking the clutch to change gear from about 5500rpm (for example) it kept the revs to this level for nearly a second before allowing them to drop back! :eek:

However a CEL indicates something is definitely wrong somewhere in the system, so it's quite likely a failed MAF sensor. Do an ECU reset and if you get uneven idle initially, then it's probably this...

Hope this helps!
Richard

Just had the maf, idle control and tps off the car.

Gave 'em a good clean and put it all back together....oh no he thought as he realised the tps can be rotated through about 15 degrees....

reset ecu...cel code 31...tps

moved tps a bit.

reset ecu...all ok.

still behaves in the same manner as earlier, so no extra damage done.

but i did notice the revs blipping slightly during gearchange, eg it would go from 3000 to 3250ish then down, so it may well be the tps like Dark Blue Mark said.

Any body got an idea on price new/used and how to set them up properley??



All help very much appreciated.

Eddie