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lee16v · Posted: Mon Sep 08, 2008 4:00 pm Post subject: Auto choke.

Hi chaps.
Could some kind soul on here explain to me how the choke works on the 16v. I've encountered some early start up problems that seem to me as if the choke isn't operating properly (if at all).

Thanks, Lee

BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

Here’s my best shot at explaining. There are 4 pipes attached to each throttle body, which are located after the butterflies. These pipes are connected to a plastic housing which has other pipes going to it for fuel vapour recirculation, which is then connected to a pipe which connects to the front of the plenum chamber to the vacuum valve. This valve is controlled by the ecu and allows more air to flow when the engine CTS says the engine is cold, acting like a chock.
Bad starts are usually caused by a faulty CTS or the valve need adjusting.
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lee16v · Posted: Tue Sep 09, 2008 2:41 pm Post subject:

Thanks for the reply Al but I'm going to be a bit dumb and ask what is the CTS? And also how can you adjust the vacuum valve?

Sorry I haven't had alook at my dizzy yet......been on holiday and also the weather is a bit crap for taking a look! but I will endevour to do so.....soon...ish.

lee16v · Posted: Tue Sep 09, 2008 2:51 pm Post subject:

Ah, research tells me it's the coolant temp sensor.......should have known that really. Embarassed

Is that the one bolted on the back of the head?

Still would like to know how the adjustment goes on the valve though.

Admin · Posted: Tue Sep 09, 2008 3:45 pm Post subject:

Hi

The valve is basically just an electronically controlled throttle that allows extra air to bypass the throttle bodies.

All the best

Keith
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BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

I havent needed to adjust one of these valves, but there are instructions somewhere that say about putting it in the freezer and loosening a screw and then re tightening it so the valve opens more when cold, i'll see if i can fish it out. Check other thing before doing this. In one of my other posts I posted the resistances you should get on a CTS, http://www.alfa-pages.co.uk/viewtopic.php?t=5575
The CTS is on the right front throttle body as you look at the engine from the outside of the car, disconnect the extension cable connected to the loom and see what readings you get, try removing it and see if the car starts aswel.
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

bobbber · Posted: Wed Sep 10, 2008 12:40 pm Post subject:

Lee,

Maybe the CTS, but could be the idle vessel - the Shiny thing on the front of the manifold.

This deals with idle and may not be opening enough to overcome the additional friction of a cold engine. Try cleaning the inside with a bottle brush and some kerosene (UK = paraffin).

Bob Cool

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lee16v · Posted: Wed Sep 10, 2008 7:39 pm Post subject:

Thanks for the replies guys. That gives me some things to look at as I'm sure it's something simple. (famous last words)

BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

sorry Lee i cant find the info Crying or Very sad

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lee16v · Posted: Thu Sep 11, 2008 3:48 pm Post subject:

No worries Al. Thanks all the same chap.

lee16v · Posted: Sat Sep 13, 2008 9:59 am Post subject:

Bob, You're a genius.

Cleaned the idle control valve (it looked a bit blackened inside before I cleaned it - silvery shiny now Wink

) and all is well again.

Next hurdle is the MOT on Wednesday. Guess I'm off to balance the rear brakes as usual Rolling Eyes

Cheers.

bobbber · Posted: Sat Sep 13, 2008 9:05 pm Post subject:

BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

and not modest in the least Laughing

I think I will give mine a clean and see if I can get a tighter fit around the seal as I sometimes get the start and then stall problem.
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

lee16v · Posted: Sun Sep 14, 2008 4:55 pm Post subject:

BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

I agree, hail to the bobbber, hail to the bobbber Laughing

I'm just a modest guy.
Doh! I forgot to do mine, good idea about the tape, i will give that a go
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203