autochoke

[ryncharlton]

Hi ,

as im sure some of you know , ive just bought a 1989 1.6 auto maestro.

its got a manual choke conversion on it , but it doesent seem to be very effective at all , starting from cold is quite poor and it doesent seem to give a fast idle on choke at all , same idle speed in all choke positions and when off.
I was wandering how difficult is it to get the autochoke working again, the carb seems to be the electronic type and also appears to have most of the vaucuum pipes still in tact.

thanks , ryan

[G Force]

Hi ,

I was wandering how difficult is it to get the autochoke working again, the carb seems to be the electronic type and also appears to have most of the vaucuum pipes still in tact.

thanks , ryan

Hi Ryan

It is well worth returning the car to auto choke in most cases. In the main people convert their carbs to manual choke to try and rectify faults that are usually nothing to do with the auto choke system.

The main causes of suspected auto choke problems are usually, either the vacuum switch diaphragm split or the ORFCO valve sticking open, or ignition related. It would be worth checking both the vacuum switch and orfco valve for problems before you start.

One other reason for converting from auto choke to manual is when the control unit ECU goes faulty. If you notice any tell tale signs of ecu problems such as the high temperature warning light illuminating as soon as you turn on the ignition when the engine is cold, or the gauge swinging up & down erratically then you may have a faulty ecu or coolant sensor / wiring problems. If you have noticed any of these issues then it is going to be less straight forward to convert back to a fully functional auto choke.

Once you’re happy that it is the right thing to do, all you should really need to convert it back to auto choke is a working stepper motor. Just replace the manual conversion with the stepper motor and plug it in. It should then work ok if you have eliminated any problems with the vacuum switch and orfco valve, and you have no ecu or wiring issues.

[G51 NAV]

In the main people convert their carbs to manual choke to try and rectify faults that are usually nothing to do with the auto choke system. I've been preaching that for years. Poor old autochoke gets blamed for a million and one maladies. Removing it or bypassing it is only masking the real fault elsewhere.

[ryncharlton]

ah excellent , thanks
now , where can i get a stepper motor from? ive had a quick look online and cant seem to find one

[ryncharlton]

Right , received the autochoke - but first i cleaned cleaned properly and checked it was closed - the orfco valve , then disconnected.

i then removed the manual choke , and fitted the new autochoke. but.. now my starting is even worse :banghead:, it will start first try , but idle very slowly and then splutter and die. if i start it and give it some throttle it will run for a bit longer but eventually die - and smells like the mixture is far far too rich. if i then unplug the autochoke - it will start and run but only if holding the accelorator slightly - but then after a while i can leave it to idle on its own - starting is actually better with it disconnected.

any ideas? i really need this sorted as sitting their for 10 minutes after a cold start untill it will idle enough just to get it into drive - its a auto , is very tedius.

thanks in advance
ryan

[ryncharlton]

Oh , also i forgot to mention

the stepper motor makes a noise - i assume its altering the mixture - but the pin doesent move, and i also appear to have a plug of some sort on the back of my air filter box - with nothing connected to it - what should go here?

[G Force]

Hi ryan.

Have you checked the vacuum switch diaphragm (if fitted, some 1.6 auto's were manufactured before 89 with vac switches still fitted).

It is important to check that the choke O rings are not, or have not got damaged when the stepper motor was refit.

Can you describe the spare plug or take a photo?

If the vac switch is ok, warm the engine to normal operating temperature, then once up to temp remove the coolant sensor plug. With the plug removed adjust the fast idle screw to achieve an engine speed of 1150rpm, then refit the coolant sensor plug. The engine speed should drop back to idle speed 850rpm.