Van hard to start and poor idle when engine cold. Choke?

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jswagger
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Van hard to start and poor idle when engine cold. Choke?

Post by jswagger »

Hi,

I'm getting my 1987, 1.9 DG (auto) van back on the road after a couple years in the garage, however I'm having issues starting from cold and was wondering if anyone had any help? The van has had new petrol and I'm assuming it's not an electrical, timing or compression problem as it will start fine on carb cleaner.

If the engine is cold it will take a about 1 - 2 minutes of turning over (in separate goes) before firing, but will stall straight away. If I try to turn the engine over again it will fire straight away but again stall, repeat this a few times and the engine will then run lumpily on it's own, but will always try and stall if I don't blip the throttle. After a few minutes the engine will idle fine on it's own and restart straight away.

Would a choke problem cause what is happening as I've read a few threads that say at this time of year the choke won't do much? I had thought the choke wasn't operating, as according to the Haynes manual the choke pull down unit wasn't working (I've replaced this, along with all the vacuum hoses). I've also checked the choke cover (with the heating element) and appears to be fine, as is the choke valve gap (assuming I've understood the Haynes manual correctly).

So a couple of questions

a. If it is a choke problem, is there anyway I can fix the choke in the correct position manually? My reason for asking, is that the guy doing the bodywork for the MOT won't take the van until it can be started on the key to move around his workshop.

b. Any pointers and cures as to the what may be causing the actual problem?

Thanks for all your help
Last edited by jswagger on 26 May 2014, 19:14, edited 1 time in total.
1988 Caravelle 1.9 DG Auto

NicBeeee
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by NicBeeee »

HI,

Noticed you joined in 2005, so you probably know more than I but just wondering if you are cold starting it correctly or may have forgot, accelerator down back up again then crank, sorry if you have been doing this for 9 years but best to rule it out
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1988 1.9 DG

jswagger
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by jswagger »

NicBeeee wrote:HI,

Noticed you joined in 2005, so you probably know more than I but just wondering if you are cold starting it correctly or may have forgot, accelerator down back up again then crank, sorry if you have been doing this for 9 years but best to rule it out


Hi,

Thanks, yes that's the way I'm cranking it when cold.
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kevtherev
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by kevtherev »

does the choke flap close when you "set" the fast idle with the acc pedal?
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jswagger
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by jswagger »

kevtherev wrote:does the choke flap close when you "set" the fast idle with the acc pedal?

When you say close do you mean completely? Sorry if that's a silly question, but chokes are new to me.

The choke flap does operate, but leaves a circa 3mm gap

I can't post a photo at the moment as I managed to disable the accelerator mechanism today!
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kevtherev
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by kevtherev »

it should leave a 3mm gap so that is correct.
once the engine is started it should be open fully in 6 mins or less.
if all this is happening your problem lies elsewhere.

possibly too rich on the idle mixture.
check CO% should be about 2.5
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jswagger
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by jswagger »

kevtherev wrote:it should leave a 3mm gap so that is correct.
once the engine is started it should be open fully in 6 mins or less.
if all this is happening your problem lies elsewhere.

possibly too rich on the idle mixture.
check CO% should be about 2.5

Thanks,

This is new to me, so would a rich idle mixture make the starting difficult or just the idle?

One thing to add is it doesn't appear to be idling fast, like when the fast idle cam is operating?
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kevtherev
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by kevtherev »

lets get the mixture right first.. before we move on
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by kevtherev »

..and yes starting would be difficult with an over rich idle mixture
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jswagger
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by jswagger »

kevtherev wrote:lets get the mixture right first.. before we move on

E D I T.

Had a look at the Haynes manual and checking the mixture and idle is there. Not done it before but reckon it's within my capabilities.

Only problem is I don't have an exhaust gas analyser, and can't drive the van to garage as it doesn't have a MOT...

Thanks for your help
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jswagger
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by jswagger »

Any recommendations for a suitable exhaust gas analyser?

Can it be any flue gas analyser as I might be able to get one from work?
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by jswagger »

An update,

Bought a Gunson Gastester and if I've used it correctly, the CO level is 1.3 at idle.

Looking at the Haynes manual, this is in spec of the 1.5 + or - 0.5%.

Will do another test tomorrow to see if I get a different result

So if the idle mixture is ok, any idea where to look next?

Thanks,
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kevtherev
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by kevtherev »

That's good news, I am assuming that figure is from a warmed up engine.

when cold, before starting and you depress the accelerator fully, does the choke flap close off the throat?
then does it open fully after 6-8 mins

Do you know what and where the fast idle cam is?
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jswagger
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by jswagger »

kevtherev wrote:That's good news, I am assuming that figure is from a warmed up engine.

when cold, before starting and you depress the accelerator fully, does the choke flap close off the throat?
then does it open fully after 6-8 mins

Do you know what and where the fast idle cam is?

Done the Gastester again today it's 1.2, both times with a warm engine.

The choke does close off the throat when you depress the accelerator fully, but not as much as usual today. (it seemed)

I've read about the fast idle cam, not sure I could identify it properly. On one (and only one) of the times it's spluttered into life, the engine has revved fast as though the fast idle is working. However, at the moment when it fires, it seems to idle at normal revs, ie the same revs as when the enines is hot, even though the engine is cold
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Re: Van hard to start and poor idle when engine cold. Choke?

Post by kevtherev »

interesting thread here for you to peruse

http://forum.club8090.co.uk/viewtopic.php?f=37&t=116284" onclick="window.open(this.href);return false;
AGG 2.0L 8V. (Golf GTi MkIII)

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