Idle Control Valve

[travelman]

I have an uneven tickover with the revs surging up and down slightly and stalling ocasionally.When I remove the wire off the end of the idle control valve the tickover reverts to normal,but as soon as it is reconnected the surging starts again.I have cleaned out the valve but it does not make any difference.Is this a likely valve failure or would it be an electrical problem.Have checked carefully for air leaks but nothing is apparent.What happens if the wire is left disconnected-does it cause starting or running problems.
If it does need a valve,what is the difference between a £35 job or a £200 one as they seem to range between these prices on ebay.Anyone recommend a particular brand.

[jamescarruthers]

I had an unbranded one on my last car and it did the trick-- it was midrange in price.‎

I think there are two types, the difference being the orientation‎ of the pipes.

You've checked useful stuff there. Would also suggest checking that the throttle position switch is checked. This controls the valve. With the engine off (so you can hear it) and in the engine bay, can you hear the switch click if you slightly open the throttle‎? Check this when cold and again when hot.

[Alan 480]

as the revs are changing it does sound as if th control valve IS working /activating so mayb emore likely to be the switch? (ie switch sending or nt sending aasignal to the ECU? )

[travelman]

Thanks James-I have checked the control switch as you advised and the clicks are conspicuous by their absence! Will get another one and give it a try.
It will not hurt to change it anyway as the one on it has never been changed in 27 years.Will get back when I have changed the switch.

[jamescarruthers]

It doesn't necessarily need replaced, it could just need adjusted. ‎

[travelman]

Yes,you were right James,it was the throttle posistion sensor.Got a Bosch one off Ebay and changed it.The old one was full of oil which was probably the problem.Now engine running fine.

[jamescarruthers]

Ah that is good news, well done. It's a good thing these sort of parts are fitted to other engines so we can keep our 480's running well.

[Alan 480]

Yes,you were right James,it was the throttle posistion sensor.Got a Bosch one off Ebay and changed it.The old one was full of oil which was probably the problem.Now engine running fine.

Mine was similarily full!!!, I drilled a hole in the bottom to let the oil out!!!

this is caused by any oil in the air inlet system running down the throttle spindle into the switch

[travelman]

Alan,I have to give you top marks for ingenuity.You always think outside of the box.

[Alan 480]

Alan,I have to give you top marks for ingenuity.You always think outside of the box.

just 'ticht',
and I like to think that 'where there is a will, there's a way' , probably coming from a time when internet didn't exist and if you needed a part you had to source it from the dealer (at high price) , local breakers yard (2miles away) or try and see what was wrong, ie a fixer NOT a fitter

actually I had a spare switch anyway from a breakers so nothing to lose, so they now BOTH have drain holes

[Irolllowvo]

Hi Alan
I've been having a similar issue, after buying a car with dead turbo oil seals. (Definite oil in intercooler pipework and inlet, since drained and throttle etc cleaned)
I tried a spare tps (not guaranteed to be working) and had the same idle after going though all other tests and possibilities I could think of, earths, icv, temp switch, wiring, crank sensor, ecus etc.
I'm wondering where you drilled the Holeand what size it was? I'd like to try your trick, obviously I wouldn't want to go deep to avoid damage.
Thansk
Ed

[Alan 480]

Hi Alan
I've been having a similar issue, after buying a car with dead turbo oil seals. (Definite oil in intercooler pipework and inlet, since drained and throttle etc cleaned)
I tried a spare tps (not guaranteed to be working) and had the same idle after going though all other tests and possibilities I could think of, earths, icv, temp switch, wiring, crank sensor, ecus etc.
I'm wondering where you drilled the Holeand what size it was? I'd like to try your trick, obviously I wouldn't want to go deep to avoid damage.
Thansk
Ed

Ed
you can check the resistance of the TPS at both ends of travel with a multi meter
first off I had a TWO litre (N/A) so at your own risk!!!

I think it was about 1/8" and all the way through to let the oil out

I'll look for the spare and send a photo (assuming it also has a hole in it!)

[Alan 480]

photos here (maybe) on google drive, as a shared item


Bosch 0280 122 001


I reckon I've not done this properly (again)

[jifflemon]

Photo's working a treat Alan!

[Irolllowvo]

Sorry I never replied Alan, thankyou for your images.
I managed to rectify the issues, there must have been previous damage to the lambda wiring and a bare wire piggyback earth had been twisted on but was making poor contact, spade connectors later and she was running a treat