[Benchai]

Wondering if there's any likely problems with my 1L before I start a wild goose chase.

Cruising along today at highway speed when engine dies. Taking foot of throttle and re-applying gently and it comes back to life. Press hard and it dies again. No cough or splutter, just dies then comes back running smooth. Will build revs to a point before cutting out, but if I give it some then it dies straight away. Say it cuts out at 4000 in second, pulling into 3rd it will run no problems until 3500 when it dies, then the same into 4th.

I have replaced the fuel filter and checked/cleaned what I can get to on the carby without removing completely. It seems to me to be either the fuel cut off valve or even an ignition problem given how it doesn't starve for fuel - it's either off or on. It seems to run fine for the first 5 k's or so then plays up consistently.

Engine is standard except for an electronic dizzy out of 1.3

Any ideas I'd be very grateful.

[atari4x4]

could it be a lazy fuel pump?

[Benchai]

I guess it's possible. It pumps ok on idle but that doesn't say it's not struggling with the volume of sustained higher revs. Explains why it would run from startup ok for 5 k's or so then start to play up.

[joe5701]

what atari said or maybe a bit of shit in the float valve and the bowl aint filling quick enough? or the choke stuck on?

[mrw82]

check the fuel filter for air bubbles when the engines running. I had it once in my zook and the flared pipe at the tank had a crack and the fuel pump was sucking air.
I spent ages trying to pinpoint what was causing it, replace plugs, leads, points, fuel pump, filter, drained tank and put fresh fuel in. I got to a point where I was running directly off a jerry can straight to the fuel pump and it would rev out past 6 grand no problem, reconnected to the fuel tank and it wouldn't go past about 4 grand unless I built the revs slowly. it was then I looked at the fuel filter WITH ENGINE RUNNING and noticed air bubbling in...... I was then able to trace it back to the flared pipe.

[Benchai]

mrw82 wrote:

check the fuel filter for air bubbles when the engines running. I had it once in my zook and the flared pipe at the tank had a crack and the fuel pump was sucking air.
I spent ages trying to pinpoint what was causing it, replace plugs, leads, points, fuel pump, filter, drained tank and put fresh fuel in. I got to a point where I was running directly off a jerry can straight to the fuel pump and it would rev out past 6 grand no problem, reconnected to the fuel tank and it wouldn't go past about 4 grand unless I built the revs slowly. it was then I looked at the fuel filter WITH ENGINE RUNNING and noticed air bubbling in...... I was then able to trace it back to the flared pipe.

Sounds exactly like what mine is doing. Shall check out the filter tomorrow, and if it looks good I'll get a new fuel pump and see how that goes

[mrw82]

along the lines of what I suggested, it could be a leak in the line anywhere up to the fuel pump and it would suck air, after the pump it's pressurised so will leak out, but before the pump it's suction.
check all the flexible hoses and maybe try running it off a jerry can straight to the pump, bypassing the whole fuel line and tank etc before spending the money on a new fuel pump

[woo603]

I think it is an air leak as well. I had the same problem in one of my old cars, the leak was on the exit side of the fuel filter near the tank, just a small cut in the hose.

I only found it because the dust around it was wet, as the other guys have said this is probably an air leak you just have to find it( can be a pain in the arse)

Hope this helps

[Benchai]

So I now have new flexible fuel lines, a new fuel pump and a clean carby. I know the fuel shut off valve/circuit is ok, as is vacuum advance. I still have my problem though. Tomorrow night out comes the fuel tank and I'll pressurise the suction side of the fuel line to make sure there aren't cracks or leaks there. I'm fairly certain the problem is with fuel, as if I switch off during a dying phase the tacho drops, so I assume there is power to the coil. It's not so bad as long as I don't go over 3500 rpm. With a 1l though that's bad enough!! Thanks everybody for suggestions. I'll keep you posted and hopefully find a cure

[mrw82]

another idea could be a blocked tank breather. if the tank can't breathe then after sucking fuel for a while it will either stop the flow of fuel or suck the tank in on itself. try running the engine/going for a drive with the fuel cap off.

[Benchai]

I now have a very clean fuel tank, and no leaks on the suction side of the fuel pump. All breathers etc are clear, and I have swapped the coil with still no change. AAAAAGH

[royce]

Are you able to get it to a point where it dies and you can clutch it and turn it off straight away and pull over to check if the float bowl is empty?

I had a drama once where youd take off or go from any point of no throttle to a lot and it would die and do nothing then pick up and go, was like there was accel enrichment, went through it all trying to figure it out, 4 new plugs and problem solved!

[Benchai]

royce wrote:

Are you able to get it to a point where it dies and you can clutch it and turn it off straight away and pull over to check if the float bowl is empty?

I'll give that a go in tomorrow's daylight.

I hooked up a timing light to eliminate spark from the equation, and sure enough, engine is dying but still has spark. Tonight before I go home I'll blow the fuel line backward and if that doesn't make a change I'll put a line into a jerry can. It's so weird because it's so consistent, and it just happened, no warning or gradual deterioration.

I keep hoping that it broke all on it's own, so maybe it will fix itself too

Can't complain though, this is the first grief it's given me

[Benchai]

Thank you all for your advice. After all that, I can say that my fuel tank is clean, the piece of garden hose that annoyed the shit out of me rolling around when it got down to half full has been evicted. I have new fuel lines, new fuel filter, and a clean carby. What was causing all this grief was the rubber boot between the carby and air box.

Go figure

Now I can get back onto my winch bar

[joe5701]

[quote="joe5701"]what atari said or maybe a bit of shit in the float valve and the bowl aint filling quick enough? or the choke stuck on?[/quote]
yeah thats what I ment

[neofitou]

Benchai wrote:

Thank you all for your advice. After all that, I can say that my fuel tank is clean, the piece of garden hose that annoyed the shit out of me rolling around when it got down to half full has been evicted. I have new fuel lines, new fuel filter, and a clean carby. What was causing all this grief was the rubber boot between the carby and air box.

Go figure

Now I can get back onto my winch bar

Oo

I just remembered reading this I had the exact same issue on my 1l.
Sorry I didn't remember when I read your original post!

[Benchai]

I was only half right. What I found today was a big arse mud wasp nest in the silver hose that goes from the air box through the inner guard. It had corrugations on about half the lump, so while it was in place air could get past, but for some reason it came loose and more fully blocked the pipe. That bastard has stayed put coming on and off during the build and now decides to dislodge. Lucky I saw it, if I put the new air cleaner back together and the piece of conduit to keep the rubber boot open and then still had the same problem I would have been tearing more hair out......