GTA atmo idling problem

I hardly use my atmo over the winter. Instead I start it up each week and idle it for about 20 minutes to get it up to temperature. Yes - I know it should be used more!

When doing this today, after a couple of minutes the idle speed went up to 2000 rpm and stayed there for a couple of minutes.I switched off after this as judging by the temperature gauge, it had got hot very quickly. I also noticed a slight burning smell, which may have been the clutch?

I guess the problem is choke related, rather than carbs (the car has always idled perfectly and has never needed any attention to the carbs). Perhaps the cold weather was a factor in this?

Does anyone have any ideas (I'm not good technically)?

I suspect you are right in your assumption that the cold weather has a lot to do with this, as there is a timer relay which will hold the idle rpm high for about 15 mins if the car is left stationary and not driven reasonably hard within that 15 mins, and the oil temp remains low. However the fast temp rise could be due to freezing of the coolant in the rad if the car was outside in sub zero temps plus windchill effect. How good is your antifreeze? a long shot perhaps, but quite possible if it is very cold where the car is kept. The smell is unlikely to be coming from the clutch if the car is stationary as you imply, more likely a bit of surface oil burning off due to high temp.

I hardly use my atmo over the winter. Instead I start it up each week and idle it for about 20 minutes to get it up to temperature. Yes - I know it should be used more!

When doing this today, after a couple of minutes the idle speed went up to 2000 rpm and stayed there for a couple of minutes.I switched off after this as judging by the temperature gauge, it had got hot very quickly. I also noticed a slight burning smell, which may have been the clutch?

I guess the problem is choke related, rather than carbs (the car has always idled perfectly and has never needed any attention to the carbs). Perhaps the cold weather was a factor in this?

Does anyone have any ideas (I'm not good technically)?

You might (for some reason) had an air lock (hence why the temps rose up very quickly) and the result is the water heating to the carb was too cold to activate the autochoke facility (or didnt even get there..).

As an aside, it is not a good idea to run the engin weekly, without taking the car for a run for at least 20mins. A better option if you do not wish to run the car, is to disconnect the battery after a run, the flip battery connector is useful for this, reconnect when you wish to go for a run, having remembered the radio code!! push the computer reset button, start and go. I have done just this for many years as I am often away for long periods of time, and not had any trouble. Notwithstanding the above, these cars need to be run on the road, they like it and it keeps everything working.

Thanks John/David.

Will try to use it more, or buy another to commute in and keep my old one in nice nick!

Update

Started car up today. Tried to see if was an air lock by squeezing the coolant hoses with expansion tank cap off.

This didn't cure the 2000 rpm idling.

On trying to drive, the throttle felt very stiff and would only go down about a quarter of it's travel. There were no problems with the throttle the last time I drove it ( a couple of months ago)

When its idling high, and warm, take of the top of the air box cover and tap the single butterfly, it might be sticking...

[Alpineandy]

Does the GTA have a 'wax cylinder' auto-choke like the A310?
If it does, I've adjusted them a number of times by either ;
1) bleed some air from the pipes to/from the autochoke (difficult), with the expansion bottle raised.
2) tap the autochoke 'body' with a small (pin) hammer.

If neither of these work, replace the cylinder (was £5 or £6 from renault a few years back).
Cheers

On trying to drive, the throttle felt very stiff and would only go down about a quarter of it's travel. There were no problems with the throttle the last time I drove it ( a couple of months ago)

It sounds like a linkage problem to me, I would check the wheel that the throttle cable is attached to by the carbs, and make sure that it is returning to the correct rest position, and the cable has not jumped out of the groove, and causing it to jam. or is there something caught under the pedal. Also make sure all the linkages are running free and not stiff at the carb end by turning the above wheel.

[/quote]

Checked the wheel the throttle cable is attached to by the carbs - linkages seem ok.

Took plasic cover/clutch foot rest off pedal box - didnt seem to be anything getting in the way of the accelerator.

Also looked at the butterfly under the airbox cover. It was closed with engine cold and could be opened by tapping it. On running engine, butterfly opened (fully when at fast idle) and could be closed by tapping it. It then immediately opened fully again. After switching off, the butterfly closed gradually (taking a couple of hours to close fully). Is this the correct way for the butterfly to operate?

It does appear to be working correctly, but if I explain how I understand it should work, it might help. As you say when cold, the butterfly is closed, after starting the butterfly opens gradually as the engin warms up, so it is fully open when the engin is at normal running temperature. From your discription it appears to be ok. However as mentioned before, there is an anti pollution system which, on starting engin, a delay relay operates, which via a solonoid valve, allows the vacuum in the manifold to marginally open the two other butterflies in the twin barrel carbs to create a fast idle, which when correctly set would be about 1100rpm (possibly 2000rpm if incorrectly set) The relay holds that rpm until one of three things happen. 1. The relay times out after about 15mins. 2. Oil temperature rises to a certain level. 3. Fast acceleration , on the road only. causes the 2 barrel butterflies to open sufficiently to trip a microswitch on its linkage. Thus the revs drop to the level held up by the decreasing rpm of the auto choke. Hence my comments above about taking car on road for a burst for at least 20 mins. As you can see it is not a simple system and requires a certain knowledge to check all functions. If you feel the above is a bit confusing (it took me a long time to get to understand it) I suggest you get someone to check it over with you, pity I am so far away!!! One other thing you should check is the condition of all the vacuum hoses from the manifold to the advance capsule on distributor and from there on to the two barrel actuator capsule then on to the solonoid valve, and back to the manifold. Any splits or leaks in those hoses can cause all sorts of problems. Hope this helps you.

John

Andy, Did you ever get to the bottom of your fast idle problem. I would be interested to know, and it might help someone else in the future. John

Yes, its fixed now

It was the fact the the linkages to the carbs were very stiff. A first, I didn't realise they were not supposed to be that stiff!

Just sprayed area with lots of WD40 and freed the linkages.

Thanks for your advice