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Struggling fulvia

  • 19-03-2018 9:24pm
    #1
    Registered Users Posts: 4,358 ✭✭✭ kev1.3s


    So I've been struggling to get this fulvia running right and have done a compression test about a month ago. Basically she has been running pretty rough which was diagnosed as an issue with the drstributer so I replaced it.
    Now it's running much better but there is no ignition from cylinder no.3 I've taken the plug out and I am getting a spark but after cleaning them off and replacing it I still get no detonation but backfire through the carb. I know the obvious answer is a stuck valve but as I've said I did have compression a very short time ago, I will do another test to make sure when I get a chance.
    Is there any other reasons why it won't fire?


Comments

  • Registered Users Posts: 4,472 ✭✭✭ Seweryn


    Try to put a new spark plug in. It may be sparking when taken out, but not when back in the engine head.


  • Registered Users Posts: 4,358 ✭✭✭ kev1.3s


    Seweryn wrote: »
    Try to put a new spark plug in. It may be sparking when taken out, but not when back in the engine head.

    I will try a new set of plugs but I took out plug no1 and swapped it with plug no3 and it's the same story.


  • Registered Users Posts: 4,358 ✭✭✭ kev1.3s


    I think it has to be the obvious really.


  • Registered Users Posts: 663 ✭✭✭ Tazio


    Hi Kev... spent a few month working on a twin carb Nord engine fun fun fun.

    Backfire tru the carb(s) may be timing or lean mix.. but if is only on one cyl then I wonder if there is a vacuum leak to that cylinder on the carb side? ie lean mix etc. Do you have a 'carbtune' or vacuum gauge to connect to the carb(s)?

    https://www.carbtune.com/carbdtls.html

    I found this tool very handy..


  • Registered Users Posts: 4,358 ✭✭✭ kev1.3s


    Tazio wrote: »
    Hi Kev... spent a few month working on a twin carb Nord engine fun fun fun.

    Backfire tru the carb(s) may be timing or lean mix.. but if is only on one cyl then I wonder if there is a vacuum leak to that cylinder on the carb side? ie lean mix etc. Do you have a 'carbtune' or vacuum gauge to connect to the carb(s)?

    https://www.carbtune.com/carbdtls.html

    I found this tool very handy..

    The fulvia has two twin barel solex's so it could be a lean mix on one of the fuel mix screws, which is what I'm hoping but would a lean mix wet the plug?


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  • Closed Accounts Posts: 8,600 jca


    It’s hardly a cracked distributor cap. I’d concentrate on the ignition side first until I was satisfied there was a good spark at the correct time at that cylinder.


  • Registered Users Posts: 4,358 ✭✭✭ kev1.3s


    jca wrote: »
    It’s hardly a cracked distributor cap. I’d concentrate on the ignition side first until I was satisfied there was a good spark at the correct time at that cylinder.

    That taught had crossed my mind, I don't particularly want to give omicron £120 for one to find out. Might borrow one from another fulvia owner to find out before I take the plunge.


  • Closed Accounts Posts: 8,600 jca


    kev1.3s wrote: »
    That taught had crossed my mind, I don't particularly want to give omicron £120 for one to find out. Might borrow one from another fulvia owner to find out before I take the plunge.

    That’s fairly scaldy for a cap alright. Are the segments in good nick? A close check under a strong light with a magnifying glass should show any tracking between the segments or between no.3 and earth. Is there any excess slack in the shaft at the rotor arm?


  • Registered Users Posts: 663 ✭✭✭ Tazio


    a
    kev1.3s wrote: »
    The fulvia has two twin barel solex's so it could be a lean mix on one of the fuel mix screws, which is what I'm hoping but would a lean mix wet the plug?


    Hello again Kev... ah yes. My nord has twin Solex ADDHE C40's... good fun playing with them. Without being able to check the vacuum on each barrel it can be difficult to diagnose (Well for me anyway being an amature). I've read of some experts listening using a rubber hose. There are default settings you can set the carbs to to just get the car running; ie close all screws and back off by 2.5 turns etc.. but I'd leave the carbs for now and check the electrical stuff for now... once you start messing with carb setting you're down a long road... ask me how I know... :pac:

    A wet spark plug would be a rich mix or no spark at all... Do you have a timing gun with the pick up clamp? while the engine is running move the clamp along each of the four leads to see if each lead is actually firing with the spark plug in place. (watch for electrical shock and keep your spare hand off the bodywork). What does the spark plug in the offending cylinder look like? check the spark gap... you could slightly close it as an experiment to see if that helps,

    Also your distributor: are the points new /set up ok? the distributor itself is it in ok condition? ie the timing lobe not worn etc...

    as said above the cap itself might have some arc tracking to the 'bad' plug. if it were my cap I'd spray the inside & outside of it with a can of electrical contact cleaner (not WD40 etc) and clean out the inside and leave to dry overnight in the house... then fire up the next morning..... e130 for a new cap is sore!


  • Registered Users Posts: 4,358 ✭✭✭ kev1.3s


    So I did a compression test today and got 130 psi on cylinder 1 and 2, 101 psi on cylinder 3 ( the troublesome one ) and 108 on cylinder 4.
    It seems to me that it should fire up on 101 psi if cylinder 4 runs on 108.


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  • Registered Users Posts: 4,358 ✭✭✭ kev1.3s


    So I replaced the distributer cap and whilst I still have some issues with tuning I do at least have a 4 cylinder fulvia.
    Thanks for any help it was appreciated.


  • Closed Accounts Posts: 8,600 jca


    That's good you're getting somewhere. If you could get your hands on a colortune plug it would help with sorting the mixture.


  • Registered Users Posts: 4,358 ✭✭✭ kev1.3s


    jca wrote: »
    That's good you're getting somewhere. If you could get your hands on a colortune plug it would help with sorting the mixture.

    That's. my next port of call.


  • Registered Users Posts: 663 ✭✭✭ Tazio


    Great to hear there is progress!
    Points and timing would be good to check and set now...

    Best of luck.


  • Registered Users Posts: 4,358 ✭✭✭ kev1.3s


    Tazio wrote: »
    Great to hear there is progress!
    Points and timing would be good to check and set now...

    Best of luck.

    I have put in a pertronix ignition system so I've no points but I will get the timing right before I go at the carburettor.


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