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Thread: Bogging down

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    Bogging down

    Hi all, got a series 3 petrol that hasn't run in years. Runs fine now but when I put it in any gear and attempt to move it bogs down and stalls. It felt like a slipping clutch so checked that, not great so replaced. Also changed leaky slave and old flexi hose. Still does it, almost like the brakes are binding but they aren't. Got it on stands and all works great but any load and it plays up. Clutch is engaging well. Pedal feels good, bleeding was no problem. Any ideas????

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    JDNSW's Avatar
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    If you have established on stands that the transmission and all wheels are moving freely, this suggests that the engine is not capable of producing a reasonable amount of power when it is required. (possible the handbrake is not always releasing fully)

    Assuming it is a four cylinder engine, likely problems are -

    Throttle is not opening fully

    Incorrect timing, ignition more likely, but valve timing possible. Distributor automatic advance perhaps seized.

    Poor fuel delivery - air leak on suction side of pump, faulty pump, restriction between pump and carburettor, blocked jet etc

    Intake manifold air leak

    Ignition issues - points gap too small, faulty capacitor, faulty coil, broken earth wire inside the distributor that breaks the connection when the automatic advance operates (this more or less hidden)

    That is about what I can think of at the moment.
    John

    JDNSW
    1986 110 County 3.9 diesel
    1970 2a 109 2.25 petrol

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    Quote Originally Posted by JDNSW View Post
    If you have established on stands that the transmission and all wheels are moving freely, this suggests that the engine is not capable of producing a reasonable amount of power when it is required. (possible the handbrake is not always releasing fully)

    Assuming it is a four cylinder engine, likely problems are -

    Throttle is not opening fully

    Incorrect timing, ignition more likely, but valve timing possible. Distributor automatic advance perhaps seized.

    Poor fuel delivery - air leak on suction side of pump, faulty pump, restriction between pump and carburettor, blocked jet etc

    Intake manifold air leak

    Ignition issues - points gap too small, faulty capacitor, faulty coil, broken earth wire inside the distributor that breaks the connection when the automatic advance operates (this more or less hidden)

    That is about what I can think of at the moment.
    Thanks for your input. I have done a compression test and it wasn't too bad. I believe the tune isn't the problem here. It starts well and runs smoothly, revs fine, etc. The handbrake operation is fine as are all the wheels. This seems to be something harsher that revs just won't overcome. As mentioned it felt like the brakes were binding, though they aren't. This is all on a flat, clean surface at the moment, not game enough to try a slope. If the clutch was knackered I would say it was slipping and not putting the power through to the driveline, but it does. Am I missing a basic LR thing here re hi/low, transfer case? Thanks again

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    JDNSW's Avatar
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    If the vehicle is on a level hard surface it should be possible to push it by hand, although it is heavy. If it is a slipping clutch, the engine will rev without moving rather than "bog down".

    One possibility is that if you can spin each wheel freely with the wheel jacked up, but the wheel bearing is loose, putting weight on the wheel may effectively apply the brakes. In this case, obviously the wheel bearing need adjusting.

    Is it by any chance fitted with an overdrive? If this is the case, and you are trying to start off with the overdrive engaged, performance will be very poor. (and using overdrive in first or second gear risks damage to it.

    There is no "Am I missing a basic LR thing " that I can think of, although it does need to be pointed out that by modern standards this is very low powered for the weight of the vehicle. Have you tried operating in low range? This should enable you to move it, and even a short distance should show signs of warming on any brake drums that are dragging.
    John

    JDNSW
    1986 110 County 3.9 diesel
    1970 2a 109 2.25 petrol

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    Quote Originally Posted by JDNSW View Post
    If the vehicle is on a level hard surface it should be possible to push it by hand, although it is heavy. If it is a slipping clutch, the engine will rev without moving rather than "bog down".

    One possibility is that if you can spin each wheel freely with the wheel jacked up, but the wheel bearing is loose, putting weight on the wheel may effectively apply the brakes. In this case, obviously the wheel bearing need adjusting.

    Is it by any chance fitted with an overdrive? If this is the case, and you are trying to start off with the overdrive engaged, performance will be very poor. (and using overdrive in first or second gear risks damage to it.

    There is no "Am I missing a basic LR thing " that I can think of, although it does need to be pointed out that by modern standards this is very low powered for the weight of the vehicle. Have you tried operating in low range? This should enable you to move it, and even a short distance should show signs of warming on any brake drums that are dragging.
    Hi JDNSW, thanks again for your help. I can push the car so am inclined to think the wheel bearings are not affecting it. There is no overdrive fitted and I am only trying this in low range 2wd. Back to basics now. Despite starting and running well I thought I'd look at the actual tune. Points were very poor so have replaced them, condenser and plugs. Have had to order rotor, cap and leads. It has been running very rich so will adjust mixture and timing when it goes back together. Will check, again, for vac leaks but there is a manifold vac gauge fitted and it reads well. Will let you know but I hope this is it otherwise I'm stuck. Cheers

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    JDNSW's Avatar
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    I should point out that low range is always four wheel drive - or did you mean with free wheel hubs disengaged?
    John

    JDNSW
    1986 110 County 3.9 diesel
    1970 2a 109 2.25 petrol

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    Quote Originally Posted by JDNSW View Post
    I should point out that low range is always four wheel drive - or did you mean with free wheel hubs disengaged?
    Yellow lever up, red lever forward, front hubs set to 2wd

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    That is high range 2wd.
    John

    JDNSW
    1986 110 County 3.9 diesel
    1970 2a 109 2.25 petrol

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    Quote Originally Posted by JDNSW View Post
    That is high range 2wd.
    For normal driving, no load. Correct?

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    Yes. My point was, try low range to get the vehicle to actually move enough to warm up any dragging brakes.

    But my suspicion is that the engine is way down on power for some reason.
    John

    JDNSW
    1986 110 County 3.9 diesel
    1970 2a 109 2.25 petrol

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