over revving

[Chris H]

can any1 tell me wot this cud be. after i have giv my car a it of a thrashing the car seems to tick over at 1500 until i turn it off and turn it bak on. does any1 no what it cud be?

 

[KDF]

could just be the ECU adjusting to the way your driving, and enriching the fuel mixture ?

still it shouldnt affect your idle speed.

 

[Chris H]

do u think cleanin the carb wiv carb cleaner may help? thats what sum1 else suggested

 

[STICKER TWONK]

Didnt think it had a carb

 

[Horace]

it hasnt got a carb fool, its fuel injected .....

 

[Mikey16vClio]

R u driving like that from cold cause i think it seems to do it for a good few minutes if its been abused. Not sure though.

Or your not letting oil get up to temp before booting it maybe?

 

[KDF]

yes my 172 revs up to 1500 rpm when I just start it on a cold morning, but it quickly drops back down to normal once it heats up a bit.

possibly a faulty sensor ? making the ecu believe that the car is cold so its brining the revs up ?

 

[Tom_16v]

Could be a knackered sensor on the speedo cable

 

[adiclio16v]

yep sounds like speedo cable sensor fault, ull be needing a new speedo cable

dont think it will be an easy job to change hehe

adi

 

[Just Bob]

We are talking SPEEDO cable.

Not too bad to do. Book time is 1/2 hr.

Quick guide.

Remove speedo cable from head and disconnect the wiring.. Tie a bit of string to the end. Go to the passenger footwell and find where the cable goes through the baulkhead. Pull the cable from behind the heater box until you have the string in your hand. Go to the engine bay and disconnect the speedo cable from the gearbox. Remove the grommet going through the baulkhead and pull the cable into the engine bay. Tie string to new cable and gently pull the string guiding the cable though the baulkhead, behind the heater box. Reconnect the electrics, fit cable to head. Job done!

Hope that helps.

Bob RTE

 

[Chris H]

cheers for that mate thats shud help me