Auto-choke (yeah Diesel owners, I know: Choke, Shmoke..)

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mnde
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Auto-choke (yeah Diesel owners, I know: Choke, Shmoke..)

Post by mnde » Thu Jan 12, 2006 5:13 pm

I'm just interested to know exactly how this works, when set up properly.

I know on some cars you have to depress the accelerator once to activate the auto-choke; some kind of fast-idle ratchet cam or such-like.

But with the BX the manual tells you not to touch the accelerator when starting from cold. I know to begin with the strangler flap should be shut so that the mixture is richer by excluding air, then the bimetallic thermostat thingie gradually opens the flap when the coolant passing through the hoses to the choke housing reaches a certain temperature, to achieve the necessary lean-ness to meet emission standards.

But is there supposed to be a faster idle speed from cold, as well as the rich mixture? My BX, like the Meteor before it, requires accelerator assistance when very cold, and for the first few minutes the idle is quite rough, and the engine is susceptible to cutting-out. After only a short time it's all fine and smooth as you like. In those vital first moments, the idle speed is no faster than normal, hence the need for manual assistance from my right foot. On my GSA it's easy: pull out the manual choke all the way, and it revs up high like a Flymo!

Any thoughts? I know you dieselists have it easy in this regard! :P

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland

jeremy
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Post by jeremy » Thu Jan 12, 2006 5:50 pm

The Weber carb choke is operated by a thermostatic capsule which seems to be situated at the top pf the carb and is heated by water. It also controls the idling speed by linkage to the accelerator linkage. there are detailed instrcutions for setting it but if nothing is happening as seems likely I'd have thought the problem was likely to be no heat (ie blocked water hose or water part of the capsule), siezed linkage - free off and lubricate, or failed capsule - replace.

1st test - observe hot and cold - does anything move? can it be moved by hand?

There are detailed instructions in Haynes for setting (looks like 3 pages or so!)

I expect the Solex is similar - look for the water pipes and work from there!

jeremy

adamskibx
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Post by adamskibx » Fri Jan 13, 2006 12:18 am

Yep the Solex works in the same way as the webber from what I can tell from the TRS. It idles at about 1400 and then drops off gradually after a few minutes when the thermostat opens the flap. Ill have a look at mine whn im next down there to see if there is a linkage that gives some movement to the throttle lever. Id imagine thats how it keeps the idle speed high.

tim leech

Post by tim leech » Fri Jan 13, 2006 9:01 am

When it works! Ive had two 16 Petrols, both started no probs from cold but could be a bitch to start when warm! One you would have to leave for 10 mins too cool down if it really had a moody that day

Again buy a diesel, and smile! Or a Late model 16TXi would a good buy!

Wouldnt mind a TZi auto if I could ever find one!

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mnde
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Post by mnde » Fri Jan 13, 2006 9:25 am

My old Meteor (pictured on the left) embarrassed me on several occasions. It didn't like short journeys. Twice it refused to start when taking work colleagues back to work after pool/beer at the local. The first time we abandoned it having drained the battery and walked back :oops: and I called out the AA at the end of the day. The second time I knew what to do: take the air cleaner pipe off the carb and stick a screwdriver down the throat to keep the strangler flap open a tad. After short journeys I would find it stuck shut, and the only way to restart would be to adopt this method! Once restarted, I could withdraw the screwdriver and the flap would stay a little open as it should...

Luckily my new Meteor doesn't have this problem! But it will only start second time from cold, and its a bit rough/low revs for the first couple of minutes. I'll investigate this linkage to the throttle lever...

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland

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cavmad
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Post by cavmad » Fri Jan 13, 2006 12:52 pm

We know someone who`ll have a spare unit if you get stuck don`t we? :wink:
Vauxhall apologist.

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mnde
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Post by mnde » Fri Jan 13, 2006 1:16 pm

Perhaps Billy ought to have the Daley & Boycie cup for BX Salesman of the week :D

Yeah, I know where to call if I need any BX petrol bits! ;)

BTW have you still got any 185 BX/Pug wheels and tyres?

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland

tim leech

Post by tim leech » Fri Jan 13, 2006 1:45 pm

Or you could buy a diesel!

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mnde
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Post by mnde » Fri Jan 13, 2006 1:58 pm

I'm not ready to cross over to the Diesel Side just yet.

But I do admit my petrol consumption is piss poor at the moment :(

Am interested in turning my dead Meteor into a 19D or a 17TD tho, if the right donor car came along. But I need to move out first!

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland

adamskibx
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Post by adamskibx » Fri Jan 13, 2006 5:10 pm

Yep I will have a spare unit, whether it works though is a mistery. When I had the GT running with its bad head gasket, before I tried to fix it, the car would start and idle fast, but never really slowed down to 850 RPM or whatever it should. It stayed at 1300 or something, and it wasnt the accelerator adjustment that was to blame. The TRS engine has a different and newer looking carb, and not only does it have a vacume advance hose for the distributor, but it has another small vacume hose coming off the front of the carb to inlet manifold section and I havent yet traced where it ends up and so have no idea what it does. The later engine also has a different oil breather system with a pipe going into the camshaft cover, so I assume it was all modified to overcome the shortcomings of the early cars.

By the way if anyone wants anything off the TRS, let me know. Tim Leach is having the spoiler, Tom the aircon, classic2cv has had the TZD type wheeltrims. The interior is very good in terms of seats. Its the thick woolly grey type material. Doorcards good, one-touch sunroof works, as do all the windows. Its got the rear headphone jacks and power supply. Good glovebox. The offside doors are great and in darkish grey. Bonnet A1, headlamps etc.

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cavmad
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Post by cavmad » Fri Jan 13, 2006 5:16 pm

mnde wrote:Perhaps Billy ought to have the Daley & Boycie cup for BX Salesman of the week :D

Yeah, I know where to call if I need any BX petrol bits! ;)

BTW have you still got any 185 BX/Pug wheels and tyres?

Mark.
Unsure whether I have any 185`s but plenty of 165 and 175 70 14`s though if you can send me the exact size of 185`s you want I`ll bet I`ve got some here somewhere.
Vauxhall apologist.

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mnde
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Post by mnde » Fri Jan 13, 2006 9:44 pm

I think the BX GTi/TD tyre is a 185/60 R14, and a Pug 405 is a 185/65 R14. My BX is on 165/70 R14 and I'm looking to upgrade so I can fit those fleabay TZD/Gti trims! :)

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland

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cavmad
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Post by cavmad » Sat Jan 14, 2006 9:45 am

I`m 99% sure I have 185-65-14`s here, don`t think I have any 185-60`s though.

Back on topic, can you not convert your car to manual choke if you are having problems with it?
Vauxhall apologist.

jeremy
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Post by jeremy » Mon Jan 16, 2006 10:58 pm

To return to the original topic - AUTOMATIC CHOKES - Bob Smith has excerpts from the Citroen workshop manual on his site

http://www.rwbsmith.plus.com/citroen2/

Some BX 16 info under the 14 folder - you'll know what I mean when you get there!

jeremy

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mnde
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Post by mnde » Mon Jan 16, 2006 10:59 pm

Thanks Jeremy, that's a useful link! :)

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland