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  1. #11
    Join Date
    Jan 2003
    Location
    PRESTON, LANCASHIRE, ENGLAND.
    Age
    62
    Posts
    136
    hi eggbert
    I have fit brand new plugs as a result of fitted ali heads because they have to be longer reach. the only things I havnt changed are the module and/or capacitor in the HEI dissy but I am convinced it has got something to do with fuel delivery. I am going to bypass the filter king tomoz to see if that makes a difference, if not I will strip the carb down again
    graham

  2. #12
    Join Date
    Mar 2006
    Location
    Oxfordshire
    Age
    66
    Posts
    1,303
    Graham,

    There should also be a fuel filter between the tank and the fuel pump - have you checked this is clear?

    My gut feel is that this is an ignition issue. I had exactly the same symptoms on one of my European tours. I'd just filled up with fuel, and when I got back onto the Autobahn it started hesitating on hard acceleration and when under load going uphill. I suspected bad fuel, bit it turned out to be the LT spade connector on the ignition coil. The connector was wrapped in insulating tape, and appeared to be sound. But when I removed the tape the connector fell off - the brass female terminal had snapped internally, and it was only the insulating tape holding it together!

    This caused an intermittent connection that appeared to work OK under light load, but failed under acceleration.

    If you have had several spitbacks through the carb, then if you have a vacuum advance canister on your distributor I suggest you check that too. In my case, the pressure of the spitback split the rubber diaphragm inside the canister - this resulted in a vacuum leak and much higher cruise fuel consumption. My fuel bill for that tour was much higher, and I now always carry a spare vacuum canister in case of a recurrence.

    Hope this helps.
    Alan

    CRC Thames Valley Regional Rep
    UK Rep for European Cobra Club
    Dax Tojeiro DeDion - Huddart SBC 383

  3. #13
    Join Date
    Jan 2003
    Location
    PRESTON, LANCASHIRE, ENGLAND.
    Age
    62
    Posts
    136
    hi conrod
    I have a filter between tank and pump which I have not checked but cant see it being that cus the bowl in the filter king which is between the pump and carb is always full, the car is ticking over ok and no probs when I rev it high, it just dies and coughs and sometimes backfires when I take it out for test drive and floor it that's why I am now thinking it could be something on the ignition side like the module or capacitor in the HEI dizzy, it seems to do it under heavy load
    graham

  4. #14
    Join Date
    Feb 2002
    Location
    Bradninch, Devon, U.K.
    Posts
    2,248
    Have a look inside the dizzy cap
    I recently replaced mine as the contacts had corroded over time
    Car now runs smooth as a smooth thing from smoothville
    CHRISC - SW REG REP - Cullompton DB No.46
    Expert on French Motoring Tribunals

  5. #15
    Join Date
    Jan 2003
    Location
    PRESTON, LANCASHIRE, ENGLAND.
    Age
    62
    Posts
    136
    cleaned dizzy cap contacts are fine, as I say car runs sweet as a nut on tickover and light acceleration, it just wont accelerate on hard throttle

  6. #16
    Join Date
    Jan 2003
    Location
    PRESTON, LANCASHIRE, ENGLAND.
    Age
    62
    Posts
    136
    it has been suggested to me that it could be the diaphram in the advance and retard canister on the dizzy that is the cause, been told to remove from carb, block off the holes and give it a try, any thoughts on this suggestion
    graham

  7. #17
    Join Date
    Mar 2006
    Location
    Oxfordshire
    Age
    66
    Posts
    1,303
    Graham,

    If the diaphragm is split, then although it will cause a vacuum leak and weak mixture at idle/cruise, it's unlikely to make any difference at all at WOT/heavy acceleration. You can easily check it by removing the vacuum pipe at the carb end and sucking or blowing on it - if you feel no resistance, then it's split. As I mentioned previously, the pressure wave from the spitting back through the carb my well have caused the diaphragm to split, but it would be a consequence of the underlying problem rather than a cause.

    Have you checked all the high and low tension ignition leads and connections, and your points and the condenser if you have them? I still suspect your problem lies in this area.
    Alan

    CRC Thames Valley Regional Rep
    UK Rep for European Cobra Club
    Dax Tojeiro DeDion - Huddart SBC 383

  8. #18
    Join Date
    Nov 2008
    Location
    Guildford
    Posts
    261
    I had some work done on my cobra recently and after picking the car up, it performed similar to yours. It ticked over fine, drove as normal when applying gentle throttle, but when putting the foot down, it really hesitated and coughed. Today, I had a look at the timing and I am guessing they set the timing with the Vac still connected as it was ticking over at 9 after tdc. (with vac disconnected) . I set the timing again to what it should have been and all good now.

  9. #19
    Join Date
    Jul 2012
    Location
    NW England
    Posts
    240
    Sounds very similar to an issue I had earlier this year, wax convinced it was ignition but turned out to be fuel. OK mine is EFi but to little fuel is too little fuel.
    I have a filter between the swirl pot and HP fuel pump and it seemed that wax getting blocked (think it's happening again too). Don't know how as it's already been through two filters prior to this.

  10. #20
    Join Date
    Feb 2007
    Location
    Bradford, West Yorkshire, England.
    Age
    61
    Posts
    2,264
    Have you checked your accelerator pump jets and diaphragm to check that the former aren't blocked and that the latter is not perforated or torn. 10 min job so worth checking. If you are bored with the Edelbrock I have a Race Demon Carb that I will be selling shortly although it may be a bit big for yours.

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