Fuel starvation?

[CliveChafer]

I tried to accelerate up a hill yesterday and the car just started to die. You could feel it pulling back. When I got to the top, I was able to let off the accelerator, and then it seemed fine when I needed to accelerate again. But then it happened a second time, and when I arrived at my destination 5 miles later, I revved the engine, and as it got above about 3000, it started to die: the more welly I gave it, the nearer it came to stalling. I let off the accelerator, and it recovered. I took out the tank when I got home, and it looks really clean, with the only foreign body being the chain that anchors the filler cap! I checked the float chamber, and there is some black sediment in the recesses at either side of the outlet. I've had the carb out several times recently, so it was very clean a couple of weeks ago. Where do you think the problem lies? There's a filter in the tank (looks clean), and the fuel pump has a fine gauze filter, so nothing should get beyond that. But this sediment in the float chamber does look very fine indeed. Suggestions?

[KeithL]

Have you checked the filter in the fuel pump to see if there is anything collecting there and to check the gauze filter has not been damaged in any way and is letting fine muck through?

Your starvation problem sounds similar to one I had. It turns out the nearly new fuel pump wasn't pumping properly and it became most noticeable at high revs or under load. Disconnect the fuel pipe to the carburettor, put it in a jar (a large coffee jar with a hole in the lid works well for this) and turn the ignition on. The fuel pump should click regularly and pump fuel into the jar in an even way. If it doesn't then the fuel pump may be the cause of your fuel starvation. Unfortunately I can't remember the figure for how quickly the fuel should pump. We ended up swapping the fuel pump again, but this time we went for an electronic one and so far no problems.

Please take suitable precautions to prevent a fire when doing this.

[mobylette]

I believe bmcecosse stated a pint a minute would be a good flow rate.

[CliveChafer]

Thanks, guys. I know it pumps quite a lot, because I did take the line off the carb and put it in a glass jar and let it run, and it clicked away merrily and filled the jar. But I didn't do anything scientific like measuring the amount over time. I'll try that as soon as I get the tank back in. And I'll check the filter for splits and gunk. I did this a while ago and it was ok then, but clearly something is getting through to the carb. I don't have an air line, so it's hard to get a good jet of air through the fuel line or carb ports, but I'll do what I can to make sure they're clear. Any further suggestions gratefully received!

[palacebear]

Have you got a flexible pipe between pump and carb? If so, is it starting to perish internally?

[les]

It might be a faulty plug, if you've got a spare set try them. I had a similar issue pushing hard up a hill, easing off it was fine. New plugs sorted it.

[CliveChafer]

The car broke down completely last weekend, had to get towed. The tow truck driver thought he could see sparking in the distributor (not at the points). I went for it and changed the car's polarity and put in an Accuspark electronic ignition distributor. The misfire has finally disappeared and the car is running great – EXCEPT it keeps stalling. If I'm in stop-start traffic, it stalls every time I have to stop. The idle speed is set higher than it should be, but the revs still drop to zero when I have to slow to a stop. When you start it again, it idles fine (if a bit rough). Any ideas?

[oliver90owner]

Have you checked for any leakage into the manifold. At high vacuum and low flow, the fuel/air ratio may be weakened. Fuel level in the carb may be another posdibility. There may be other causes. Dash pot full? Need a decoke or valve grind?

[liammonty]

Another thing that springs to mind is the timing, given that you’ve just changed the distributor. Are you confident you’ve got it set right? Glad you’ve nearly got to the bottom of your problem, by the way - did you figure out what part of the distributor it was causing the trouble? I’m not surprised it wasn’t the carb - they are generally more reliable than the ignition system!