Automatic to Manual Choke Conversion

[G Force]

I am personally much happier now that I am in familiar territory and I have less electronics to go wrong!

Thanks for the advice,
Ben

Hi Ben.

Fair enough Ben Sorry we couldn't manage to "convert" you, but at least you're happy with your car now and it's another Maestro running well & on the road.

Cheers,

G Force

Well the vacuum switch seemed fine (I could not suck air through it) and the plunger in the ORFCO valve was free and created a seal when I sucked on it. I triple checked all the breather hoses and they were in perfect condition, yet the idle was still all over the place, so I decided to do the conversion. It now starts and idles lovely.

Sorry to have given up on the 'E' carb, but I am personally much happier now that I am in familiar territory and I have less electronics to go wrong!

Thanks for the advice,
Ben

Don't want to be a wet blanket but from my own very recent experience, one split in a vacuum hose could well be just the beginning. I thought I had sorted the poor running by fixing a split on the pipe from the ecu to the carburettor, where it plugs on to the ecu. Then I found the pipe from the 3-way connection on the back of the carb was split too, so replaced that. Then I found the 3-way itself was coming apart (perhaps because I'd just been waggling it) so had to make a replacement for that. Then, checking the results with the engine cold, I found the top of the petrol pump swimming with petrol, from a split in the input pipe. This was all within 24 hours. I suppose if all the pipes are the same age, when one perishes, the others are all ready to split in sympathy.
But, it runs much better now.

[TLC]

As someone who went from Auto to manual for 6months years ago then back again.!!!DONT do it its not wroth it and is far easyer to sort out the running problems which will the give you years of hic up free motoring

[G Force]

Are the two wires to cut the fuel supply after the ignition is turned off? If I removed them would it still cut the fuel supply on overrun? Thanks,
Ben

Hello Ben.

The valve was never used as an anti-run-on device when you turn off the ignition on the Maestro & Montego. It was tried to be used for this purpose by freight rover on sherpa vans but proved even more problematic than as an ORFCO device.

If you do remove the wires the overrun fuel cut off stops functioning yes. The valve was reputed to save 2 to 3mpg full urban cycle when the cars were new, in reallity the unreliabillity wasted more than it saved, not to mention the damage to the cars / systems reputation.

The automatic choke + vacuum switch in working order & properly maintained, for the average car user was more economical than compared to a manual choke.

[threelitre]

When my HIF44E had trouble it was always the electrical connection to the stepper motor. It either left the 'choke' out or did not do anything on a cold morning...

Regards,

Alexander

Are the two wires to cut the fuel supply after the ignition is turned off? If I removed them would it still cut the fuel supply on overrun? As that is the only feature of this carb that makes me want to keep it! I will test the valve asap (well probably whenever this rain decides to stop!) and post up the results.
Thanks,
Ben

[G Force]

Thanks for the replies. I take it the ORFCO valve is the thing with wires connected to it, on the opposite side of the carb to the stepper motor? How can I test it?.

Hello Ben.

Yes that is the ORFCO valve.

You need to make sure the ORFCO valve is not stuck open. To do this, remove the valve by undoing the three screws.

When you look at the valve body (the bit where the gasket goes) there is a small oval hole at the end furthest from solenoid (the bit that the two wires connect to). Suck on that hole to see if you can get it to stick to your tongue. (Yuk)

If you can suck air through then the valve is stuck open and you need to close it. To do that, unscrew the solenoid from the body and free the plunger with WD40 then refit the solenoid and recheck the hole is now sealed.

Once you have refitted the valve do NOT reconnect it, as they are a constant source of unreliability. The best way is to just tape up the wires with insulation tape to make sure they cannot short out on the engine, and just forget about them.

When I was investigating the other day I noticed one of those rubber hoses to the vacuum switch was completely split, I was hoping that would be the problem but I have replaced it and it made no difference.

Any leaks in these vacuum pipes will have a dramatic affect on how the engine runs whether hot or cold. You can sometimes find that vacuum pipes have been leaking for quite a while and gone unoticed, then someone has come along and tinkered with the carb mixture screw richening the mixture to try and improve the poor running. You then fix the leak in the vacuum pipe and the engine then runs too rich when hot & cold and runs just as bad.

A faulty vacuum switch + a vacuum leak would probably end up making the engine run a little worse when you fix the vacuum pipe leak, but I would still test it as a matter of illimination.

Thanks for the replies. I take it the ORFCO valve is the thing with wires connected to it, on the opposite side of the carb to the stepper motor? How can I test it?

When I was investigating the other day I noticed one of those rubber hoses to the vacuum switch was completely split, I was hoping that would be the problem but I have replaced it and it made no difference.

[G Force]

problems with the idle and cold starting, and I suspect it has somehting to do with the poor MPG.

Hello Ben

I couldn't agree more with the advice you have been given by Rich (austin rover) it is far better and easier to fix the old carb than go down the manual choke route.

As well as the ORFCO valve & stepper motor O rings, another componant on the carburettor that when it fails causes all 3 of your symptoms is the vacuum switch.

To check the vacuum switch first you need to move the air filter box out of your way.
1. Disconnect one end of cold air hose from air filter box or bonnet slam panel.

2. Remove one end of the large hot air hose that fits on the filter box & on the exhaust manifold hot air shroud.

3. Remove the 3 large screws from the air filter box, no need to remove the small posi screw that secures the lid.

4. Swing the air filter box out of your way; it will still be attached to the engine by a small vacuum pipe underneath. Note the rubber gasket on the air filter box around the air outlet to carb.

Once you can see the carb look for the vacuum switch it can be seen attached to carb on (The round device with a vacuum pipe connected, in the 3rd picture). Pull off the small vacuum hose then remove vacuum switch from the carb by prising it from the two rubber hoses with a suitable screwdriver. Test diaphragm for any air leaks by sucking on the small single vacuum port. (If you suck on the vacuum connection you should not be able to suck air through). If you can suck through the switch you need a new one LZX 2292 will be OK.

Test it and let us know what you find, if it is faulty we can offer advice on setting up the carb again once you fix the other faults.

Regards, G Force

[Austin-Rover]

Some reading for starters...

http://www.maestro.org.uk/forums/showthread.php?t=3102

[Austin-Rover]

Infact, having read your post again, if you're having problems with cold starting and idling then it's likely there's nothing at all wrong with the original carburettor and your problem lies with the ORFCO valve and the auto choke stepper motor.

The ORFCO valve can be disconnected and the O rings (the problem part) in the stepper motor replaced. Tending to both improves the reliability of the auto choke.

[Austin-Rover]

You can get yourself a carb overhaul set from Burlen Fuel Systems for £30 or so, and quite possibly avoid a lot of building and bodgeing getting parts from other cars to fit.

I'd be more tempted to do what i can with the original carb before embarking down the DIY route!

Hi everyone,
My maestro has a HIF44E on it at the moment, which I'm planning to get rid of as it's causing problems with the idle and cold starting, and I suspect it has somehting to do with the poor MPG. I have a metro HIF44 to put on it but I am having problems with where to mount the throttle cable. The mini/metro spacer plate bracket thing which the throttle and choke cables mount to would sit directly underneath the maestro air box, meaning I either need a new way of mounting the throttle cable or a different air box. I have ordered an Ital cable as the maestro/montego cable does not reach the front of the carb and the Ital one is 4 inches longer.

I suppose my questions are, is there another airbox I can use which doesn't interfere with the cables, and has anyone else done this conversion and know of any other problems I might encounter?

Regards,
Ben