Here's an interesting tickover problem

[sledgedog]

Just wondering if anyone out there has ever had the same problem as me. I have this very intermitent tickover problem, had it last year and it went away and it has very recently come back. Only ever seems to happen when the engine is warm and up until today I have never been able to replicate it in the workshop. Basically the engine refuses to tickover at less than 2-3000 rpm although sometimes it does hunt between 1000 and 3000. Makes driving in traffic interesting when it occurs as there seems to be no real loss of power and the car will quite easily drive along without the old accelerator pedal applied! Car is a 1992 S3. Today however it happened whilst I was fiddling with it in the workshop. Just as the radiator fan cut in the revs shot up to 2000 and stayed there. I therefore decided to remove the connector to the tickover control valve and the revs immediately returned to normal. On replacing the wiring, apart from a brief burst of revs, the engine ticked over at 1000 which is normal for my car. I cave replaced the idle controller within the last year,it did the same with the old one, as well as every other sensor apart from the fuel temp one. Have had a code reader on it and the ecu reports no errors. Any ideas would be appreciated!

[WildfireS3]

Throttle pot???

[walsingham]

Same car, same problem. Turned out to be the throttle pot.

You know when you phone up an IT helpline and they tell you to switch off the computer and reboot - whatever the probem? Judging from my first year of ownership, throttle pot is the reboot equivalent. hasn't anyone made a bomb proof one yet?

[rnd]

It sounds like the "throttle position sensor". I replaced mine with the same symptoms as you and it cured it, 6 months later it went again("ford replaced it) but also check at the air filter, i had those wire connections corroded (found it by accident) when i touched the wiring harness the engine cut out. Cleaned the connections and and now all ok

Good luck

[M@H]

It sounds a bit like the idle speed control valve is playing up... it might not be the valve itself though, it could be the seal between it and the plenum leaking some air.. acordilgly, changing it would nto solve the problem.. ?

Cheers
Matt.

[sledgedog]

Thanks for the ideas everyone. Just wired a new connector block for the good old throttle pot to eliminate poor contacts here so will see if that works. Idle speed valve has had a good clean up of it's contacts and a healthy dose of carb cleaner. Maybe just maybe these will sort out the problem. Just running the engine and what should happen, the bloomin' pipe that connects the swirl pot to the water pump decided to spring a leak. Oh the joys of TVR's : Think I will go back to painting the chassis!

[shnozz]

walsingham said:

hasn't anyone made a bomb proof one yet?

you can adapt a cerbera throttle pot and that apparently is more bomb proof. Best person to answer this is LeeBee, who went through 3 pots in about the same number of months. IIRC Johno also fitted the cerb one on his S1.5.

I replaced a mate's TP on their S the other day - Ford are now charging almost £50.

edited to say - just checked the tvrgear website and a cerb throttle pot is only £20 as well.

>> Edited by shnozz on Wednesday 18th February 11:46

[john mac]

Throttle Pot for the S2 - todays price from my main Ford dealer £67 plus VAT - seems a bit overpriced from whats been said before?

[plfrench]

Surely Ford didn't have these problems with the throttle pots on the sierra's and Granada etc. what is the difference that is causing the S to have such problems?

Paul.

[shnozz]

john mac said:

Throttle Pot for the S2 - todays price from my main Ford dealer £67 plus VAT - seems a bit overpriced from whats been said before?

thats odd - i ordered one for my mate about 3 weeks ago and I am 99% certain it was under fifty quid. and that was from Hendy Ford

Chandlers Ford branch if thats any help