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  • Car starting and idle problems

    Had some fun and games with the frost this morning. I couldn’t get the key into the lock on the driver’s door, and was only able to get in through the passenger door.

    I then was able to open the driver’s door with some difficulty from the inside, but not able to close the door as the mechanism froze.

    So I started the car and went to get some warm water to de-ice the windows.

    Unaware the door mechanism was frozen and thinking it was broken I proceeded to strip the door trim off to have a look. While doing this I switched the engine off as it was chugging away blowing out loads of fumes.

    On discovering that the door was not broken I used a screw driver to lever the mechanism back into the correct position so I could close the door. Feeling quite pleased with myself for solving the problem I went to start the engine again.

    The engine wouldn’t start. Despite turning over it wouldn’t fire. This was the first time since 1992 it hasn’t started. On that occasional I had called the AA out and the mechanic showed me a little trick where he unscrewed the dashpot plunger on the carb, and by pushing it in and out while turning the engine over was able to get it to fire. Lucklily this technique worked this morning.

    The mechanic said whenever Maestros or Montegos don’t start it was always this problem and this same solution.

    The problem for my car however, seems to be as follows:

    Despite hearing the stepper motor working, I couldn’t see the rod moving. Now the idle has been very rough when cold for a while and uneven when warmed up and fuel consumption has shot up. Sometimes the car ‘kangaroos’ on light throttle when cold. The two rubber O rings were replaced with viton O rings 80,000 miles ago. I fairly sure the vacuum hoses and connectors are in good shape. The orfco valve was disconnected a few years ago. Where else should I investigate?

    One thing is for certain, I was late for work, and if the car is to continue as the primary source of transport (i.e. kept out the scrapyard), this cannot happen again!
    Burgundy 1987 Maestro 1.6L
    173,000 miles.

  • #2
    Hi,

    Check the vacuum switch diaphragm on the side of the carb. 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.

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    • #3
      I've just checked the vacuum switch this lunchtime and I think I can suck through the single hole for the vacuum hose connector. I didn't stay out too long as it was too cold. Thanks GForce, spot on as usual.
      Burgundy 1987 Maestro 1.6L
      173,000 miles.

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      • #4
        Oops, Rimmer Bros want £53 plus VAT for a new vacuum switch. Can anyone suggest another supplier?

        Update. Theres one in the club spares page. Will enquire tonight.
        Burgundy 1987 Maestro 1.6L
        173,000 miles.

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        • #5
          Originally posted by D813YBB View Post
          I've just checked the vacuum switch this lunchtime and I think I can suck through the single hole for the vacuum hose connector. .
          Hi.

          If that is the case, then until you get a new vac switch the best thing to do is to remove the vacuum pipe from the switch and plug it up with something suitable. (Plug the vacuum pipe not the vacuum switch its self ).

          This won't fix the problem, but as long as the CO has not been reset whilst the diaphragm was split, it should improve things until you get a replacement switch. If you get any problems just let us know

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          • #6
            Just one further question if I may.

            I’ve checked the EPC which lists five types of vacuum switch. Some types are used depending on the carburettor model. My car did have a carburettor change early in its life, so I’m not sure which model is fitted.

            There are vacuum switches ‘K’ and ‘yellow spot’ listed on Ebay, and I’m unsure which one to order. Does it make any difference?

            Mine is fitted with the auto choke.
            Burgundy 1987 Maestro 1.6L
            173,000 miles.

            Comment


            • #7
              Originally posted by D813YBB View Post

              There are vacuum switches ‘K’ and ‘yellow spot’ listed on Ebay, and I’m unsure which one to order. Does it make any difference?
              Hi,

              The correct one for your car is LZX2292. as this is the modified vac switch for all 1.6 carbs, when they came out they were stamped Z and had a black dot. Of course any of the others is better than a faulty vac switch but they are all different and will have effect on how the car runs whilst it is on choke, all will cause the engine to run slightly over rich on idle during warm up and some will be too lean under acceleration during warm up.

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              • #8
                Thank you G Force.
                Burgundy 1987 Maestro 1.6L
                173,000 miles.

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                • #9
                  Here you go

                  http://cgi.ebay.co.uk/Austin-Maestro...item19b5140a8e

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                  • #10
                    Good News

                    The new vacuum switch has been fitted and I now have a super smooth fast idle. The standard idle is also much improved but may need some fine tuning of the idle and mixture screws.

                    However the chugging, kangaroo-ing and vibration of the past few months have all been banished.

                    I would like to thank G Force for his advice.
                    Burgundy 1987 Maestro 1.6L
                    173,000 miles.

                    Comment


                    • #11
                      Originally posted by D813YBB View Post
                      Good News

                      The new vacuum switch has been fitted and I now have a super smooth fast idle. The standard idle is also much improved but may need some fine tuning of the idle and mixture screws.

                      However the chugging, kangaroo-ing and vibration of the past few months have all been banished.

                      I would like to thank G Force for his advice.
                      Hi D813YBB,

                      You are more than welcome, glad you have had a good outcome. If any fine tuning of the carb is needed you can find plenty of info in my S series tuning guide in the FAQ Section.

                      Cheers, G Force

                      Comment


                      • #12
                        Originally posted by D813YBB View Post
                        Good News...

                        I would like to thank G Force for his advice.
                        In honour of Gary's always-spot-on advice I've had an idea for a new website. I'm going to call it 'BeerPal' - and the idea is that basically you can send beer to anyone with an email address. It's the beginning of an entirely new currency on the Internet!

                        I think it's a fantastic and completely original idea ;-)

                        Seriously though, I'm glad the maestro's fixed - another fine detective job by Gary
                        You can contact me by clicking here.
                        Owner of E760 DRY - Mk. 2 Shantung Gold Maestro Vanden Plas 2.0 EFi

                        If the world should blow itself up, the last audible voice would be that of an expert saying it can't be done. - Sir Peter Ustinov.

                        Comment


                        • #13
                          Send Gary a stomach pump in readiness
                          Regards
                          John Orrell

                          MG Maestro Turbos 396 and 502
                          MG ZT190+ (53 plate)

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