All right guys,
I'm working on my mates escort cosworth with the P8 Weber injection system and fitted with factory fitted a/c.
Problem is that when ever the a/c system is turned on the engine rev's drop from 900rpm to 700, often stalling the engine..
The air con works fine, the compressor can be turned easily by hand, the r134a gas pressures are spot on, no leaks.
It's 37 degrees here so I'd like to find a solution asap..
Any ideas?

 

Sounds like the ISCV isn't working properly. Either it's dirty/stuck OR there's a signal of the A/C to the ECU for idle control that's missing.

 

Sorry, forgot to mention that I changed the iscv with a cleaned and lubricated good valve, mind you, the old one I took off was perfect and not stuck at all.. the plunger moves freely.
Where would the missing signal be sent from? and if you know, which terminal of the injection ECU?
Thanks!

 

Surely the clutch wouldnt lock up unless the engine is running etc ?

Are you manually locking the clutch and trying it by hand ?

ISCV is something to look at too.

 

Yeah, i'm manually turning the front pulley by hand, turns no problem, the inner part that actually connects to the compressor's inner pistons is what i'm turning with the engine off.
I thought that the compressor was siezing up but obviously not.
I need to find out what wire sends the signal to up the rev's when the a/c is turned on.
Car idles perfectly without the a/c compressor on, as soon as it gets turned on and I hear the TAC of the clutch, bam the engine dies down and most times stalls.
Anyone know what wire is the signal wire to up the rev's?
Cheers.

 

http://www.bigturbo.co.uk/main6.htm

 

Excellent Stevie, thanks mate.

 

I'm pretty sure there is a sensor in one of the ac lines that sends a signal to raise the revs when it's turned on. I'd bet it's broke.

 

Could well be mate.
It was working fine then, out of the blue, it started stalling.
Engine hot or cold, same thing.
What I'd like to know is where do the wires from the P8 ecu that are shown on Bigturbo's web page go?
Pin 21 and 11, What signal and were does it go to? Relè? Idle valve circuit?
I've raised the engine idle using the idle adjustment screw, by raising the idle it just about holds 750/800rpm with the compressor engaged but then the hot idle with the compressor off is 1100 rpm..

 

send me your email address

 

andrew.albanese@libero.it

 

not always a good idea putting it up for all to see lol...spambots love email addresses

email sent anyway