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  • 1.6 Auto issues

    Hi All, I’m having some issues with my 1.6 Automatic. It’s a 1991 Clubman Auto, it was on an Auto choke but this was converted to manual choke some years ago.
    In the last 12 months I’ve had the carburettor rebuilt 3 times and it professionally tuned twice.
    for some time I’ve had a fuel smell, this has been thoroughly investigated, including having the fuel system pressure tested, and there are absolutely no leaks.
    when starting the car from cold it’s a bit temperamental. I have to pull the choke all the way out (it’s incredibly stiff) then the car will start but after a second will run very lumpy so I have to push the choke in a little but put my foot on the gas to keep the revs up. I have to sit like this for about 5 mins until the car has started to warm up. Once warm it drives beautifully and smooth.
    im wondering if the fuel smell is basically flooding and it’s running too much on choke and the normal idle is too low (does this make sense). Within the last couple of weeks I’ve noticed the car will run on for a few seconds after the ignition is off. If this happens when I come to restart it’s reluctant, as if starting a car once it’s flooded. It does always fire up though.

    a separate issue I’ve noticed in the last few weeks too is that it’s slow to change down through the gears. It changes up perfectly and smoothly but when slowing the engine will sometimes sound as though it’s about to stall just as it changed down a gear. Could this just be kick down cable adjustment?

    All advice is welcome!

    Thanks

  • #2
    The choke cable should not be stiff but easy to operate, it's also overfuelling quickly, once started the choke should only need to be halfway so you need to address the cable stiffness. The petrol smell, is it coming from the front or rear? As for the gearbox, it might just need draining and fresh oil put in it due to the cold weather
    1958 Ford Consul Convertible, new hood on
    1965 Ford Zodiac Executive. Back under cover
    1984 MG Montego EFi in black. Digital dash and bring worked on
    1984 MG Montego EFI in red. Digital dash and being worked on
    2004 MGZT cdti. Great workhorse
    2004 MGZT V8. Heater out as leaking

    Comment


    • #3
      Hi, thanks for the reply!
      I’ll have a look at the choke cable over the weekend. After about 5 mins I can push the choke in to the half way point but it takes some patients to get it going properly when it’s cold for sure!
      The fuel smell was in a couple of places, I originally had a leaking carb and a dodgy fuel cap, these have now been rectified but I still smell fuel. I think it’s most noticeable by the drivers door and I get “wafts” inside the car. I’m struggling to tell if it’s fuel or fumes now. Other people still comment on the fuel smell if they walk past the car when it’s parked.

      The car was serviced not long ago and I had the gearbox oil changed. I went out yesterday and I didn’t have any issues at all with it changing down.
      mot did “run on” both times I stopped though, it’s becoming much more regular now.

      Comment


      • #4
        Have you looked at the vent pipe and fuel filler pipe to ensure no leaks there? I would also jack the car up, start it up and have a long look under the car, cleaning the fuel pipe underneath as you go to the front of the car following the pipe to the pump and then behind the carb
        1958 Ford Consul Convertible, new hood on
        1965 Ford Zodiac Executive. Back under cover
        1984 MG Montego EFi in black. Digital dash and bring worked on
        1984 MG Montego EFI in red. Digital dash and being worked on
        2004 MGZT cdti. Great workhorse
        2004 MGZT V8. Heater out as leaking

        Comment


        • #5
          I would suggest there is a fuel leak somewhere between the filler cap and the engine. So many possible places on a Maestro! fuel filler neck is an obvious, but the tank itself or fuel gauge sender and the fuel lines are common. Also as someone said, a breather pipe might be blocked.

          I had a fuel smell for a long time. Found a leak on the fuel sender joint, fixed, still smelt. found a leak on the fuel filler pipe, replaced it. Still smelt. Replaced all the metal fuel line running under the car, and finally no petrol smell! I am amazed it didn't catch fire!

          Comment


          • #6
            Thanks both.
            I’m somewhat limited due to disability and using a wheelchair so I can’t get under the car myself.
            the fuel filler neck is fine, it was replaced a few years ago with aluminium.
            ive sent the car to 4 different mechanics to be checked and no one can find a leak. It’s had the tank/ filler neck/ fuel lines etc removed and checked. The carb has been thoroughly checked including under acceleration. The fuel pump has been replaced too. I also replaced the fuel cap to ensure a tight fit.
            I’m really struggling with it as I don’t have anyone to help me investigate myself, it’s also my main car.
            I’m not sure what step to take next. Everything has been checked over and over. I can only think it stems from the carb somehow.
            I drove the car last night and it drove beautifully, there wasn’t much of a fuel smell but it did run on, it seems to do that every time I turn it off now.

            Comment


            • #7
              Hi

              The cold start problem is probably mostly related to the manual choke conversion. I aren’t a fan of manual choke conversions because they never give a progressive fast idle in relation to the amount of cold enrichment, due to the shape of the fast idle cam. Having said that you should be able to improve things with careful adjustment of the fast idle speed, whilst the engine is cold. There should be an adjustment screw that comes into contact with a cam shaped quadrant on the carburettor choke mechanism. The screw can be adjusted in order increase the engine RPM whilst running on choke. As already mentioned the choke cable shouldn’t be stiff, make sure the cable is long enough and it doesn’t have any tight kinks in the cable run, then try lubricating the cable and mechanism. It also goes without saying but the ignition components i.e. spark plugs, plug leads, distributor cap and rotor arm should be in very good condition, because faulty ignition components can cause the poor running during warm up.

              Fuel smell has always been an issue at times even when the cars were new. There was a modification on early cars that involved fitting a small one way valve in the heater drain outlet in the bulkhead, and fitting a small piece of absorbent, flame retardant tube to the end of the float chamber vent tube. The problem being fuel vapour from the float chamber condensed at the end of the vent pipe forming droplets of fuel, the smell of fuel vapour then got into the car through the heater drain because of its proximity to the float chamber vent tube. The one way valve prevented any fumes entering through the heater drain and the gauze tube was to stop the alarming fuel droplets forming on the metal vent tube. Have someone check yours because later cars should have had the modification already done. Check also that the metal vent pipe from carburettor hasn’t broken off half way down its length, it should exit under the vehicle.

              The kick down cable adjustment is a good place to start with the downshift problem because it has an influence on gearbox oil pressure, not absolutely sure but I,I,R.C. it should have full travel at full throttle on your gearbox.

              Running on when switched off is usually due to the engine idle speed set too fast. Other things could be engine overheating or excessive carbon build up in the combustion chambers. If you want you could try turning the engine off in D before returning the gear selector to P.

              Comment


              • #8
                Anything G force says, is likley to be correct!

                Comment


                • #9
                  Nice to see you back Gary
                  1958 Ford Consul Convertible, new hood on
                  1965 Ford Zodiac Executive. Back under cover
                  1984 MG Montego EFi in black. Digital dash and bring worked on
                  1984 MG Montego EFI in red. Digital dash and being worked on
                  2004 MGZT cdti. Great workhorse
                  2004 MGZT V8. Heater out as leaking

                  Comment


                  • #10
                    Thanks so much for that G Force, that’s some excellent information!
                    I shall work my way through the list when the weather improves and keep you posted!

                    Comment


                    • #11
                      I think there may be an issue with the fuel tank breather Hose after all. Every time I try to fill up with fuel it keeps clicking and trying to overflow. I’m not so sure the garage did check this after all. Another thing I will look at when the weather improves.

                      Comment


                      • #12
                        Hi guys, Cheers.
                        Just to say I can see it looks like I’m not around but I haven’t really been away. I might not always be logged in but I check the posts pretty regularly. It’s just that you guys do such a great job answering posts in the technical section I never have anything to add to the advice you all contribute.

                        Originally posted by Jez View Post
                        Anything G force says, is likley to be correct!
                        Not according to my missus.

                        To the OP good luck with Maestro and roll on summer.
                        Thanks, Gary



                        Comment


                        • #13
                          Originally posted by G Force View Post
                          Hi

                          The cold start problem is probably mostly related to the manual choke conversion. I aren’t a fan of manual choke conversions because they never give a progressive fast idle in relation to the amount of cold enrichment, due to the shape of the fast idle cam. Having said that you should be able to improve things with careful adjustment of the fast idle speed, whilst the engine is cold. There should be an adjustment screw that comes into contact with a cam shaped quadrant on the carburettor choke mechanism. The screw can be adjusted in order increase the engine RPM whilst running on choke. As already mentioned the choke cable shouldn’t be stiff, make sure the cable is long enough and it doesn’t have any tight kinks in the cable run, then try lubricating the cable and mechanism. It also goes without saying but the ignition components i.e. spark plugs, plug leads, distributor cap and rotor arm should be in very good condition, because faulty ignition components can cause the poor running during warm up.

                          Fuel smell has always been an issue at times even when the cars were new. There was a modification on early cars that involved fitting a small one way valve in the heater drain outlet in the bulkhead, and fitting a small piece of absorbent, flame retardant tube to the end of the float chamber vent tube. The problem being fuel vapour from the float chamber condensed at the end of the vent pipe forming droplets of fuel, the smell of fuel vapour then got into the car through the heater drain because of its proximity to the float chamber vent tube. The one way valve prevented any fumes entering through the heater drain and the gauze tube was to stop the alarming fuel droplets forming on the metal vent tube. Have someone check yours because later cars should have had the modification already done. Check also that the metal vent pipe from carburettor hasn’t broken off half way down its length, it should exit under the vehicle.

                          The kick down cable adjustment is a good place to start with the downshift problem because it has an influence on gearbox oil pressure, not absolutely sure but I,I,R.C. it should have full travel at full throttle on your gearbox.

                          Running on when switched off is usually due to the engine idle speed set too fast. Other things could be engine overheating or excessive carbon build up in the combustion chambers. If you want you could try turning the engine off in D before returning the gear selector to P.

                          I’ve been having a tinker with the car and managed to get the cold start much improved by adjusting the fast idle. Someone has managed to put the adjustment screw in upside down which hasn’t made things any easier!

                          turning the car off in ‘D’ has stopped the running on, for now anyway!

                          as regards the modification for the fuel smell it doesn’t seem to have been done on my car. Is there some “kit” that can be purchased to fit?

                          I have a stepper motor sitting in the garage and when the choke conversion was done all the cables were left so would this literally be a case of “plug and play” or am I opening myself up to a whole new loads of problems?

                          Thankyou all for your advise, it’s truly appreciated.

                          Comment


                          • #14
                            Hi

                            I found the heater drain check valve which was one part of the modifying kit on ebay (see link Below). If your car has been factory modified (I thought at 91MY it might have), then this valve won’t fit to your car. As for the gauze tube for the vent pipe someone with access to e.p.c. might be able to locate it?

                            If you can recall the reason that prompted you to do the conversion to manual choke that may help you decide whether it’s the way to go or not. Having said all that, you could potentially encounter quite a few problems going back to auto choke. Especially if there was an extensive problem with original system or the conversion involved any unorthodox modifying of the throttle linkage (read butchery). Everything is possible with time, money and patience and the original auto choke when it is working and setup correctly is definitely more drivable than an aftermarket manual choke conversion albeit more complex.
                            I don't know if this is really much help to you but let us know what you decide.


                            Cheers. Gary

                            https://www.ebay.co.uk/itm/362879147508

                            Comment


                            • #15
                              Originally posted by G Force View Post
                              Hi

                              I found the heater drain check valve which was one part of the modifying kit on ebay (see link Below). If your car has been factory modified (I thought at 91MY it might have), then this valve won’t fit to your car. As for the gauze tube for the vent pipe someone with access to e.p.c. might be able to locate it?

                              If you can recall the reason that prompted you to do the conversion to manual choke that may help you decide whether it’s the way to go or not. Having said all that, you could potentially encounter quite a few problems going back to auto choke. Especially if there was an extensive problem with original system or the conversion involved any unorthodox modifying of the throttle linkage (read butchery). Everything is possible with time, money and patience and the original auto choke when it is working and setup correctly is definitely more drivable than an aftermarket manual choke conversion albeit more complex.
                              I don't know if this is really much help to you but let us know what you decide.


                              Cheers. Gary

                              https://www.ebay.co.uk/itm/362879147508
                              Thanks for the reply.
                              I think I’ll have to find a decent mechanic to sort the heater drain valve and set up the auto choke for me, it seems a bit out of my depth!

                              The previous owner had the choke conversion done. There was nothing wrong with it but he just didn’t like auto chokes so he had my one and his Montego converted to manual choke. He still has his Montego which is a manual transmission so runs quite happily. Mine being an auto transmission it really would run better (I think) with its original set up.

                              Comment

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