HELP! Idle speed too high!

[Pete-W]

my 16v started idleing at 1400 rpm today instead of the usual 900 it has been idleing at!

have checked the thottle cable and that fime.

what could be other reasons for it startin to idle so high?

cheers in advance

Pete

 

[iPap]

Mine did it for a while! Then it fixed itself? Lots of people have had trouble... East to sort if I remember! Someone will remember the name of the part, began with a "P"...

 

[steve_rt]

potentiometer

 

[Pete-W]

just gone to have a look at it again. idles fine at 900 rpm when 1st started up, once it was been driven for a little as a min starts idling high again. if you switch of the engine and start it up again straight away idle at 900rpm until driven again!

seems odd!

what does the potentiometer do?

also seems to be a clicking type noise coming from the engine! what could this be?

cheers

Pete

 

[BenR]

clicking is probably just the injectors.....tappets have to be heavily worn to tap majorly.

Potentiometer is the TPS and provides the ECU with throttle position data.

But i think your problem is either the ISCV or a leak in the manifold somewhere.........possibly one of the vacuum hoses.

 

[Pete-W]

sorry for the ignorance but what is the ISCV?

how would i go about finding out if it is either of these?

what would i need to do if one of the probs?

cheers

Pete

 

[Tom_16v]

Idle Speed Control Valve

 

[BenR]

potentiometer is red and on teh throttle spindle, dont touch it, its not a problem.

ISCV or Idle Speed Control Valve is the sort of cylindrical shaped thing on the side of the throttle body, with a rubber pipe comming off it, start the engine and squeeze it, it should whistle.

Take it off and give it a good clean with carb cleaner........its might just be sticky.

 

[Pete-W]

is this easy to do?

haynes manual doesnt give any info on this!

cheers

 

[BenR]

its easy yes.

forget the haynes, its only a few bolts, clips.

 

[N.D.Hill]

This may sound stupid but you will more that likely find it to be the speedo cable. There is a speed input sensor at the top of the cable which supplies road speed info to the ecu, when you change gear and lift off the throttle speed input is sent to the ecu which then holds open the ISCV so when you put your foot back down there is no big flat spot. With a faulty sensor the ecu thinks the car is moving when it is not so again holds open the valve and the revs are higher. When you turn off the ignition the ISCV is reset hence when you start the car again it behaves ok. I bet you can rev and rev the car stationary and you cant get it to idle at 1400 yet when you go over thirty mph and 4000 rpm you will get the fault. As i say it may sound stupid the car idles high because of a speedo cable but believe me we have replaced quite a few.

 

[Pete-W]

dont suppose u could give me a quick guide. only just gettin in to doing bits myself

cheers

 

[BenR]

right, doh, didnt even think of that.

 

[Infinicar]

Good point Nick - we had a similar thing happening to a customer car - replaced the ISCV, TPS etc and still happening. We then had the engine out, to do a clutch and when I put it back in I put a new speedo cable in as the old one was stretched, and hey presto no more idling issues.

Paul

 

[Pete-W]

nick u r correct, i can rev it as much as i like a not get it to rev higher.

so you saying i need to replace the speedo cable?

cheers

Pete

 

[Clio16vPaul]

mine does that... exactly the same.

 

[steve_rt]

genius!

 

[N.D.Hill]

Experience!

 

[Pete-W]

cheers, any one how much a new speedo cable roughly costs and how much it should cost to get fitted?

cheers for the help guys, much appreciated

 

[KDF]

Speedo cable will be < £20 I would imagine. Easy to fit depending on the routing of the cable (sorry dont own a valver)

N.D.Hill, anyone would think that you actually work on these cars all the time

 

[Pete-W]

is it alright to drive about till a get it done in a couple of weeks, of should i get it done asap?

cheers

pete

 

[N.D.Hill]

All depends how long you can put up with the fast idle.

You could just try removing the dash facia and j.j.j.jigling the speedo cable connection to the speedo head, cant guarantee itll work but might.

 

[steve a]

This has just started happening to mine. Did it when i put the williams dails in so i guess you could well be on to a winner there Nick.

 

[Pete-W]

now if im only out in the car for 5/10 mins it will still idle at 900rpm even if a rag it! however any longer driving and it idles at 14000 every time.

seems very odd. just cheakin it still seems like its the speedo cable

thanks again

Pete

 

[Adams_16v]

mine was doing the opposite, idling too low.....changed the speedo cable first, same problem cleaned iscv, etc etc same problem

changed it to a new ISCV and it sorted it out

 

[Adams_16v]

mate i reckon its the ISCV, mine was clicking as well like u say. if its sticking it wont let the engine idle correctly, only problem is they are quite expensive new! speedo cable is a bit cheaper to try 1st...

thats what it was on mine anyhoo! good luck