Engine won't idle

[jameshamilton]

1981 2.0l CU engine

Morning

I'm loath to start YET another carburetor thread, but I'm at my wits end with an idle speed problem that I just can't seem to fix/get fixed

First noticed this last year -- when warmed up and decelerating through the gears at e.g. a roundabout or lights, the van would stall as it came to a stop. I had the carbs stripped, cleaned, gaskets replaced etc & all seemed good

Six months later, it was doing it again. I took it to Airfix in Carshalton as I needed new petrol tank. Darren fitted that & tweaked the carbs. Driving it back from his place there were no issues at all. Didn't stall once.

Then, a week later, it's back to its old tricks. Only now, it won't idle at all -- as soon as it comes off the choke, it dies unless I give it some gas.

It's got a dual vacuum dizzy, but the lower vacuum port is blanked. There's no T-bar on the other vacuum line that runs to the left-hand carb, and the right hand carb vacuum nipple has nothing connected to it. The two vacuum connections on the air box are joined to each other (I can send a pic tomorrow)

Anyone have any ideas?

[bigherb]

Pictures would help.

[jameshamilton]

Some pics of what I'm working with, or attempting to:

Clockwise, from top left: Dizzy, with blanked vac lead, loose lead from one of two solenoids on the left hand carb; right hand carb; airbox, with vac lead "fix"

If anyone knows of a good mechanic in SE London, I'd be hugely grateful .. think this is beyond my limited skill set...

[djaychela]

There should be three things connected electrically on the LH carb - two solenoids as seen, but also a rectangular device (idle mixture enricher) which is screwed to the side of the carb and has a spade terminal coming out of it. Item 2 in the pic below.

If it won't idle at all, then I'd say you need to check if the idle air setup on the left-hand carb is working - pull the hose off the top and see if it sucks air in? If not, check the solenoid and supply, etc.

Not sure that the vacuum setup is correct, although mine has nothing connected to the right-hand carb nipple, so that's OK. The two connections on the airbox aren't connected right, nor are they doing anything at the moment. The left-hand one of them should be connected to the idle vacuum connection (which is at the back of the engine, there should be a connection visible when you look on the far (front, vehicle-wise) side of the airbox and look down. That should connect to the left-hand airbox connection, and also to the "back" of the vacuum diaphragm on the dizzy (for retard at idle, for emissions purposes). The right-hand connection on the airbox should connect to the air selector flap on the airbox inlet. However, as long as there are no leaks, I don't think that will be giving you idle issues.

(I'd say you'd want to post bigger pictures in future, it's next to impossible to see anything in the postage stamp ones here!)

(In other news, 144kB max attachment size, Really? Didn't realise the web server was also made in the 80-90s )

pdsit.jpg

[jameshamilton]

There should be three things connected electrically on the LH carb - two solenoids as seen, but also a rectangular device (idle mixture enricher) which is screwed to the side of the carb and has a spade terminal coming out of it. Item 2 in the pic below.

If it won't idle at all, then I'd say you need to check if the idle air setup on the left-hand carb is working - pull the hose off the top and see if it sucks air in? If not, check the solenoid and supply, etc.

Not sure that the vacuum setup is correct, although mine has nothing connected to the right-hand carb nipple, so that's OK. The two connections on the airbox aren't connected right, nor are they doing anything at the moment. The left-hand one of them should be connected to the idle vacuum connection (which is at the back of the engine, there should be a connection visible when you look on the far (front, vehicle-wise) side of the airbox and look down. That should connect to the left-hand airbox connection, and also to the "back" of the vacuum diaphragm on the dizzy (for retard at idle, for emissions purposes). The right-hand connection on the airbox should connect to the air selector flap on the airbox inlet. However, as long as there are no leaks, I don't think that will be giving you idle issues.

(I'd say you'd want to post bigger pictures in future, it's next to impossible to see anything in the postage stamp ones here!)

(In other news, 144kB max attachment size, Really? Didn't realise the web server was also made in the 80-90s )

pdsit.jpg

Thanks .. was working to the 114kb limit, but appreciate they're small

Here's a pic of the left hand carb. Idle-enrichment box is conspicuously absent, so I guess that could be an issue. What does that do, exactly?

[djaychela]

Yeah, that's the kiddie - the two holes have been epoxied up! IT says Idle enrichment, so it'll be adding fuel into the idle circuit - I've just taken a look at the spare one in the garage, and that passes air through it when it's cold, so I'd guess that allows fuel through normally, and then stops once it's warmed up?

However, I don't think it will be giving you the root of the problem, just meaning the engine is a bit leaner than it should be when it's cold...

[jameshamilton]

Yeah, that's the kiddie - the two holes have been epoxied up! IT says Idle enrichment, so it'll be adding fuel into the idle circuit - I've just taken a look at the spare one in the garage, and that passes air through it when it's cold, so I'd guess that allows fuel through normally, and then stops once it's warmed up?

However, I don't think it will be giving you the root of the problem, just meaning the engine is a bit leaner than it should be when it's cold...

Thanks ... generally the stalling happens when the engine is warm, so I doubt this is the root cause

[djaychela]

OK, so I'd check that the idle solenoid is working (it's on the left on the picture you posted last), and if so, that the idle inlet (the pipe which is shown at the top middle of the last photo you posted, heads down into the top of the carb) sucks air in when it is running?

I take it you've already checked for air leaks? I see the three jubilee clips at the bottom of the last photo, be worth checking everything is as it should be there and elsewhere - mine had an elbow pop off and then it wouldn't idle.

[Kieran1984]

Is airfix the place up Stanley pk rd?


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[jameshamilton]

Is airfix the place up Stanley pk rd?

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That's the place ... he told me he'd done a full tune up, timing etc on it. With the help of someone on this forum, I had a look at the carbs the other night. They weren't even close to opening together and, as for timing, god knows how he did it when there's no timing scale on the engine. I'm steering well clear of that place from now on

[Kieran1984]

I know I've not heard good things about that place either. I live in carshalton and drive past that when I take it to my mate to service lol


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[multisi]

I got the wiring for the carbs etc all original and a nice pair of low mileage carbs. You need to get everything back to the standard set up !

[jameshamilton]

Thanks. Think I'm pretty much there now ...

I got the wiring for the carbs etc all original and a nice pair of low mileage carbs. You need to get everything back to the standard set up !