It's broken and I need help!!
Discussion
Hello. Not been round these parts long so I shall give a little introduction ...
Car nut farm boy studying away in italy needs help fixing his shopping trolley so he can go to Sardinia in it to see the WRC in 10 days (and drive home in 3 weeks). Any help greatly appreciated as I'm proper stumped on this one. For more details read on.
The car is a 92 Pug 106 1.0l petrol. TU series engine with carb and manual choke, good ol' distrbutor on the end of the camshaft and breakerless points. Not standard fare round here, granted, but a car nonetheless.
The problem is an intermittent lack of go. As in the engine stops. First appeared half way up a mountain the other day and initially put it down to a lack of fuel due to a combination of empty(ish) fuel tank and successive hairpins. Anyhoo, full tank didn't help. The reason I thought it was a fuel problem was that the engine died, then 10 seconds later, more often than not it came back to life again and was fine until the next time I accelerated - just like when the carb got clogged up on the Mini. Sometimes it was 20 seconds and I'd rolled to a stop but it always came back to life. Problem continued on the flat bit back to town kangerooing along, sometimes violently (which pointed to an ignition problem), but only after accelerating (which to me sounds like a lack of fuel).
Back home we had a look at the fuel filter and although not spanky clean, was still flowing freely as far as I can see. Dismmantling the carb uncovered the expected amount of gumph but none of the jets was blocked, nor was the filter at the fuel inlet. There is a little plastic petrol bottle (for want of a better, more accurate word), mounted on the inlet manifold. It has fuel in from (mechanical) pump and fuel out to the carb and a return to the tank. Not sure of its function but this is always full of fuel when the bonnet is open so I'm assuming there is plenty of petrol getting to the carb. Carb went back together, problem not solved.
Just for s**ts and giggles I tried it with no (extremely filthy looking air filter). Unsurprisingly no different.
When I started learning about these things, father alway used to say sparks first then fuel then it'll probably work (so what did I do - straight for the fuel!!):
If it was an ignition problem, it would have packed up properly by now, and wouldn't happen so regularly under acceleration. The only possibility I can think of is poor distributor arm/cover contact, but is seems just too intermittent for that, or anything else I can think of in the sparks department.
Which leaves fuel. The instant when the engine cuts seems very sudden, not like running out of petrol at all. But the way it happens after acceleration and then comes back to life does seem like a fuel shortage. Correct me if I'm wrong but mechanical diaphragm fuel pumps either work or they don't - there's no middle ground.
What am I missing? Is there a secret blocked filter somewhere? Have I got a special half working fuel pump? Is there a lift pump somewhere that has packed up?
Or is it just because its a French car within 500 miles of cracking 100k??
Sorry, long post I know, but if you got this far, I would be very grateful of hearing any thoughts you have - including any bits of relevant Italian vocabulary...
Car nut farm boy studying away in italy needs help fixing his shopping trolley so he can go to Sardinia in it to see the WRC in 10 days (and drive home in 3 weeks). Any help greatly appreciated as I'm proper stumped on this one. For more details read on.
The car is a 92 Pug 106 1.0l petrol. TU series engine with carb and manual choke, good ol' distrbutor on the end of the camshaft and breakerless points. Not standard fare round here, granted, but a car nonetheless.
The problem is an intermittent lack of go. As in the engine stops. First appeared half way up a mountain the other day and initially put it down to a lack of fuel due to a combination of empty(ish) fuel tank and successive hairpins. Anyhoo, full tank didn't help. The reason I thought it was a fuel problem was that the engine died, then 10 seconds later, more often than not it came back to life again and was fine until the next time I accelerated - just like when the carb got clogged up on the Mini. Sometimes it was 20 seconds and I'd rolled to a stop but it always came back to life. Problem continued on the flat bit back to town kangerooing along, sometimes violently (which pointed to an ignition problem), but only after accelerating (which to me sounds like a lack of fuel).
Back home we had a look at the fuel filter and although not spanky clean, was still flowing freely as far as I can see. Dismmantling the carb uncovered the expected amount of gumph but none of the jets was blocked, nor was the filter at the fuel inlet. There is a little plastic petrol bottle (for want of a better, more accurate word), mounted on the inlet manifold. It has fuel in from (mechanical) pump and fuel out to the carb and a return to the tank. Not sure of its function but this is always full of fuel when the bonnet is open so I'm assuming there is plenty of petrol getting to the carb. Carb went back together, problem not solved.
Just for s**ts and giggles I tried it with no (extremely filthy looking air filter). Unsurprisingly no different.
When I started learning about these things, father alway used to say sparks first then fuel then it'll probably work (so what did I do - straight for the fuel!!):
If it was an ignition problem, it would have packed up properly by now, and wouldn't happen so regularly under acceleration. The only possibility I can think of is poor distributor arm/cover contact, but is seems just too intermittent for that, or anything else I can think of in the sparks department.
Which leaves fuel. The instant when the engine cuts seems very sudden, not like running out of petrol at all. But the way it happens after acceleration and then comes back to life does seem like a fuel shortage. Correct me if I'm wrong but mechanical diaphragm fuel pumps either work or they don't - there's no middle ground.
What am I missing? Is there a secret blocked filter somewhere? Have I got a special half working fuel pump? Is there a lift pump somewhere that has packed up?
Or is it just because its a French car within 500 miles of cracking 100k??
Sorry, long post I know, but if you got this far, I would be very grateful of hearing any thoughts you have - including any bits of relevant Italian vocabulary...
There is a rod that operates the diaphragm, it is in turn operated by a cam or whatever on the crankshaft. That rod can wear and cause the diaphragm only to move through a fraction of it's normal travel.
If you have checked and cleaned the distributor cap / rotor arm, I would check the connections to the HT coil and ignition amplifier. Both those can fail if they overheat too.
If you have checked and cleaned the distributor cap / rotor arm, I would check the connections to the HT coil and ignition amplifier. Both those can fail if they overheat too.
Thanks everyone.
Not expecting HT failure as they were new 4000 miles ago...but they were pattern parts so its always a possibility.
Distributor cap and fuel pump will be off next and I shall let you know what I find. If that gives nothing, I shall have to find out what the Italian for strobe light is. Back to front I know but I don't really want to be buying something else I've already got!!
Keep em coming if you suddenly have a brainwave.
Not expecting HT failure as they were new 4000 miles ago...but they were pattern parts so its always a possibility.
Distributor cap and fuel pump will be off next and I shall let you know what I find. If that gives nothing, I shall have to find out what the Italian for strobe light is. Back to front I know but I don't really want to be buying something else I've already got!!
Keep em coming if you suddenly have a brainwave.
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