Maestro 1.3 running problems

[SkyBlueSam]

My Maestro 1.3 has developed an annoying habit. It will be running fine for a couple of miles from cold or warm start and then decide to run erratically. It has always ran like a dog which I put down to the vacuum pipes. However it is now stopping completely when approching lights or a junction or roundabout . The engine will cut out completely when approaching a standstill and the battery light comes on. It will start on a turn of the key but will splutter for a bit then come to a standstill a moment later. I have noticed the engine is a lot noisier than it used to be when exceeding 45-50mph in fifth gear. It has done over 91k miles. I have tried the simple screwdriver fix by removing the rocker cover and turning the cross head mixture screw clockwise to increase revs. The engine sounds as if it over revving then dies completely. I suspect a faulty electronic control unit or the vacuum system and am hoping it will be a straightforward fix. Any ideas gratefully received. Cheers

[E_T_V]

Have a read of the tuning the A series FAQ and give it a tune up. Also might be worth checking the distributor cap and rotor arm. Also check that the distributor is clamped properly and so can't be turned by hand, (as that alters the timing).

[Guest]

My moneys on distributor cap and rotor arm. Let us know how you get on

maestro vans

[G Force]

It has always ran like a dog which I put down to the vacuum pipes.

Hi SkyBlueSam.

Have you now fixed the vacuum pipes or are they still needing to be fixed. If you have not fixed them and they are leaking they could be the cause of your running issues getting steadily worse.

[SkyBlueSam]

Many thanks for the suggestions. I have given it a quick tune and checked the distributor is firmly clamped to the engine. I have checked the vacuum pipes and there doesn't appear to be any leaks. What do I need to check on the distributor cap and rotor arm?

[G Force]

What do I need to check on the distributor cap and rotor arm?

Hi.

When checking the distributor cap, remove it and Mark the position of the leads relative to the cap and remove them. Check each turret and each lead for any signs of burning or white or green deposits. If there are any signs renew cap and the leads. Look for contamination / dirt inside and out, give it a good clean so you can check it properly.

The 4 contacts inside the cap should not be excessively burned that a light scrape with a suitable blunt blade wont remove any white deposit.

Check for any visible signs of cracking on the inside and outside.

Check the centre carbon brush for wear and signs of burning.

Check that the centre carbon brush can be pushed in a little and it should then spring back out on its own.

Remove the carbon bush by pulling it out of the cap and check the spring for signs of discolouration or burning, (if the spring stays in the cap remove it with a small screwdriver an reattach it to the brush). if ok give it a little stretch and refit it making sure the carbon is securely attached to the spring and that it still springs out when depressed.

If all looks ok the cap can be reused.

When checking the rotor arm if there are any white or green deposits on the rotor arm it should be renewed.

Check for excess carbon dust on the rotor arm if the rotor arm is covered in black dust renew both cap and rotor arm.

Check for any visible signs of cracking.

The brass contact of the rotor arm should be reasonably clean and the end of the rotor arm where the spark crosses to the 4 contacts of the cap should not be excessively burned that it cannot be cleaned by light rubbing on fine wet/dry paper.

If the rotor arm looks ok it can be checked for its insulating capacity by holding the loose end of the coil lead (with good insulated grips to prevent electric shock) 8mm to 10mm from the centre of the fitted rotor arm, with an assistant cranking the engine there should be no sparking to the rotor arm centre. If any sparking occurs the rotor arm should be renewed.

Other checks, Check the coil tower in the same way that you check the cap by removing the HT lead and examine the connection and lead for burning or white or green deposits.

Ensure the coil tower is clean and there are no visible cracks or carbon track marks.

Ensure the LT spade connections of the coil are clean and tight, rectify if necessary.

Check also the breather hose for blockages, splits or air leakage. A good check is to remove the breather pipe from the carburetter and the oil filler cap. Put your hand over the oil filler tube and then blow into the pipe, you should be able to build enough pressure to resist your breath, if you can do so remove your hand from the filler tube before you stop blowing. If you can blow freely listen to where the air is escaping, this will be an oil leak site or a hole somewhere.

A common air / oil leak point is the rocker cover gasket or the weld around the filler neck. The filler neck can be easily sealed with a smear of RTV around the outside joint. The rocker gasket will need renewing properly and retested before and after a run, as it is common for the gasket to suck in if not fitted correctly. A leaking rocker gasket will cause poor running symptoms at idle and slowing down.

You should check also the inlet manifold gasket for air leaks, by spraying a small amount of WD40 where the manifold meets the cylinder head with the engine running. If the engine note picks up or stumbles then suspect the gasket or further investigate the vacuum pipes.

Cheers.

Gary

[SkyBlueSam]

Gary, many thanks for that in depth explanation. I will let you know what I find. Cheers Craig

[SkyBlueSam]

A friend of mine who is a mechanic has had a look and puts the erratic running possibly down to it having an automatic choke and the carb being faulty. Anyone have any spare manual chokes or know where I can get one?

[E_T_V]

Usual problem with auto choke is the connections on the ECU. Unplug it and replug it in several times to clean the contacts and see if that improves things.

[G Force]

A friend of mine who is a mechanic has had a look and puts the erratic running possibly down to it having an automatic choke and the carb being faulty. Anyone have any spare manual chokes or know where I can get one?

Hi SkyBlueSam

People often wrongly suspect the carburetter and auto choke as causing a problem, then go to the trouble and expense of replacing the carb or converting to manual choke, only to find that the problem still exists.

There are two usual suspects that go faulty and cause the majority of running problems associated with the carb that can easily be diagnosed and fixed.

ORFCO valve sticking open.

The ORFCO valve is the solenoid valve on the side of the carb, 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 the wires, 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 block, and just forget about them.

The vacuum switch diaphragm leaking.

The vacuum switch is on the opposite side of the carb to the ORFCO valve, connected by three rubber pipes. 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. If you can’t source a valve straight away then leave the old valve on the carb but disconnect the vacuum pipe. Plug up the pipe so you do not to have a vacuum leak.

(In this condition the engine will run richer on choke than it should do but not as rich as it was with a faulty vac switch, it will run ok once warmed up.)

Check out these two items and if you find a fault with either then once you have fixed them you will need to reset the idle speed and mixture settings. If they are OK come back and I’m sure we will be able to help further.

Cheers

Gary

[SkyBlueSam]

"Usual problem with auto choke is the connections on the ECU. Unplug it and replug it in several times to clean the contacts and see if that improves things"

Gary, Dan thanks very much for the advice and tips. I will have a go at them and report back.

Cheers

Craig