Hi all,

Recently my Cossie has been idling fast, and a bit reluctant with the throttle 'just' open.

I've replaced the plugs, leads, dizzy cap, distributor (cos I broke the other one), and I've just replaced the ISCV and TPS. It's still idling at 1500 and still sounds hesitant (like not firing) with the throttle 'just open', but not as much as it was before.

Cold idle just starts at 1k and winds up a bit, but after that, it'll idle at 1500. And, because it's idling fast, there's not a great deal of engine braking, so I'm having to brake harder and longer than I normally would.

Last night, it wound itself up to 2k, disconnecting the ISCV (as per a similar problems I've read about) has no effect - still idles at 2k.

From what I've gathered, the only remaining things to replace/check are: ECT, vacuum hoses, the MAP sensor, inlet manifold gasket, throttle body gasket. Which of these is the most likely culprit? The base idle has been mentioned, but I've never had to touch it - it used to be perfect!

When I had the throttle body off to replace the TPS, I cleaned it out with carb cleaner...would that make a difference?

Answers on a postcard, please...

 

i would check for air leaks mate. that shud be the first step and also a free one

 

yeah airleak, normally goin to fuel regulator, or throttle stickin slightly open.

 

Yeah agree with above, sounds like an airleak to me.

Get yourself a can of 'East start' and spray it around any areas you think it might be leaking from.

If you spray it on the leak the revs will go up further.........

 

East start Not Wd40 or Damp start?

Thanks for the input guys, I'll have a go Saturday morning. Will post the results here.

Apart from a massive fuel bill, is there any other side effects that I should be worried about?

 

Sorry..

EASY START

Its very probably called something different now like Damp Start, same stuff, just the can ive got in my garage is about 10 years old...

 

easy start, the con rod bender


better use something like some solvent degreaser,

 

You say you changed the TPS, I assume you set it up properly, not just a case of fit and forget

I would check for leaks as said above (carb cleaner has been mentionned before ).

You may want to add dodgy wiring to your list, new sensors are no good if you've got a break in your loom, and we know they are getting old.
If it's a 4x4 sapph, worth cleaning the three connectors on the bulkhead with contact cleaner while you're there.

Good luck

 

You're not seriously suggesting it'll bend a conrod at idle

 

Also, do a check for any ECU codes........

 

Best way to test for air leaks is to pressure test the whole system,

i test mine to 40 psi,

i bong the turbo air filter pipe, and then pressure test the lot usin a compresser and a regular.


Also check the TPS is correctly position'd

 

Fit and forget...lol

Fitted as per the Ford Sierra/Escort Cosworth Workshop Manual. It's a 2wd Sapph - the TPS that was on it was black, and didn't look particularly old; the replacement is red (both PF01). Both had a resistance all the way around, except at what I'm guessing was the 'closed' position.

 

Really does sound like an air leak m8

I had exact same thing on mine a year or so back was the gasket on the plenum was leaking a the bottom nearest the bulkhead

 

i had one of the throttle brackets bolts come out (on the plenum cover) and the thing idled at 2k so i'd deffo go with the air leak option!

 

Had it looked at yesterday, and it turns out that the inlet manifold gasket's gone, so one's on order.

Will it do much damage driving it around in the mean time?

 

i wouldn't put your foot down, as fueling might be out due to leak.