9 replies to this topic

[Tucker SP]

Hi people,

Please ignor the post with Doc I need an apointmant.

Right my baby was running rough and then she cut out, I took off the air filter and checked inside the float chamber and she was empty. do you think it could be a dodgy fuel pump?

if so, which one shall I get, stage one with 998.

Help needed.

Cheers
Tucker

[dklawson]

Don't assume it's the pump yet. Is your current pump electric or mechanical?

If electric, disconnect the fuel line from the bowl cover, and have an assistant aim the hose into a container. Switch on the ignition. Watch for fuel and listen for the pump. If you have fuel, assume that somehow the float valve on top of the bowl is stuck or plugged. If you hear the pump but don't see fuel... is there any chance you have a plugged fuel filter? Filters can be added anywhere between the tank and the front of the car. You could also have a plugged fuel strainer IN the tank. Check all of this before you go looking for a new pump.

If your existing pump is mechanical you have to check the same things but it is a lot more work and harder on the car as you have to crank the engine to operate the pump. This is best done by pulling the spark plugs so the starter doesn't have to work so hard.

As for what pump to buy, the most common replacement I'm familiar with is the little square Facet pump which can mount on the rear subframe. Make sure you buy the low pressure one. These will flow more than enough fuel for a normal Mini. It might be questionable if you were running on the track all the time.

EDIT:
I just read your other post about this. Check your fuel filters first. Your symptoms are similar to what a car of mine did when it's fuel filter completely plugged up. It was more prone to do it under load... but it also would do it downhill (if I wasn't coasting) as debris would slosh around and block the last remaining part of the filter that was clear. Filters are a lot cheaper than pumps you know!

[adam c]

I presume you'll have a mechanical pump in which case;
When i was fitting a fuel filter and took the outlet pipe off the pump the petrol continually ran from the tank so i pressume it must be lower than the tank so this may be a good way to check if fuel is coming from the tank. You could also take off the inlet to the pump and fuel should run through by gravity, otherwise if you want to risk it blow in the tank through the filler cap to force the fuel through (I've done this many times on old diesel tractors and it works but the diesel will burn your face if you don't get off pretty quickly hence why i wouldn't recommend it unless your as stupid as I am!)
There is also a pipe accesable from the back subframe held onto the tank feed by a jubilee clip. If you remove this it will show if a filter in the tank is blocked but also spill a lot of petrol if your not careful.
Airlines always come in handy for jobs like this (if you have one) and are great for cleaning filters, fuel lines, float bowls etc.
Good luck with whatever it is...

[Tucker SP]

Thanks chaps,

Its a mechanical pump, it has some sort of filter king on, inline from the pump to the float chamber, when she was running ok I took the fule pipe off the float chamber and cranked her over and she was pumping on the floor (fuel) but seemed a bit feeble. I have NOT done the same test when she cuts out, I only took the top of the float chamber and she was empty at the side of the road, an A road so quite busy. The float looks in good nick and it all looked clan inside the chamber. i could not see inside the filter king as its alloy with green letters on (might help to see what fliter it is as I could not read the letters but can just make out King).

So what I should do is:

take her out for a spin and wait till she cuts out, pull over and take the pipe from the fule pump to the chamber off and crank her over and see what happens.

thinking about it, I will also take the king off and see the differance in the squirt with it on and off.

I will also check the flow from the tank to the pump by takeing off the pipe to the pump. Never knew there was a filter in the tank will look at that to but i think its going to be one hell of a job on the side of the road :gasp:

I will put on a normal filter on as well, as I have one in my tool box.

Do ya think the above sounds like a good idear???

I will not spark up a cigg at the same time :cheese:

Cheers
Tucker

[dklawson]

It sounds like a good plan to me... just don't put yourself in danger.

The thing in the tank is only a screen on the pickup pipe. It's coarse, but if your tank has a fair amount of rust in the bottom it can get sloshed around and plug the intake. Adam's idea of using compressed air to blow back through the lines sounds good. However, don't blow backward through what you're calling a "filter king".

I don't know what a filter king is but I assume its a nice aftermarket filter. There are aftermarket, transparent, disposable inline filters for use with the air-cooled Volkswagons. You may wish to try a fuel flow test with the filter king (open ended hose pumping into a container), then repeat the same test after replacing the filter king with the cheap disposable filter. If you observe more fuel flow leave the cheap filter in place. Of course... this may also help you determine if it's the pump itself. Your manual may give some indication of what an acceptable flow rate is. You do have a manual don't you?

The mechanical pumps should flow fuel in spurts. There should be a good gush of fuel each time the cam lobe actuates the pump then nothing. The fuel pump is driven by the cam which runs at 1/2 engine speed. For every 2 revs of the engine you'll get one pulse.

[cowboy]

something else to have a look at is the needle valve ontop of the float in the carb float chamber, if this is sticking then you won't get any more fuel into the carb, so when the float chamber is empty, the car cuts out :wales:

[Tucker SP]

Thanks people,

Not yet had a look but will do this weekend :cheese:

Went to a car boot yesterday and got me a fuel pump for a total amount of £0.50 :gasp: Bargin if you ask me.

I have got a manual so will be checking what it says about the flow :cheese:

I did have a look at the needle in the carb and oil did look to be a bit low, I only topped it up a month or two ago. will give it a nother top up, How full should it be?

Cheers
Tucker

[dklawson]

When you check the oil in the carb you are checking the dashpot, not the needle. The needle is on the bottom side of the piston that holds the dashpot oil. Some needles are spring loaded and rub against the fixed jet in the carb, others operate down the center of the jet tube and do not touch. Regardless, fill the oil in the dashpot to about 6mm below the top of the steel tube in the top of the carb. This is actually a little too much but the overflow will get sucked into the engine burned up very quickly... leaving the maximum amount of oil behind.

The needle Cowboy is talking about is on the float chamber. It is a valve that shuts off the supply to the float bowl. The level of fuel in an open float bowl will vary by carb type. Your maintenance manual will tell you how to set the float level by inverting the cover and measuring the gap between the float and the bowl cover using a drill bit or steel rod. You really need to check your manual for this measurement.

[Tucker SP]

A while back when I toped up the dash pot I toped it up to the rim, put the needle back in and moped up the oil that over spilled. Now I cant see any oil so I take it it should be the right right level???? I have noticed a spring on the bottom of the carb with some sort of adjuster on and have wondered what it was, Should I be playing with this or not?

Cheers
Tucker

[dklawson]

My experience has always been with the "HS" series carbs. If your carb is something different you'll need to refer to your manual for specifics. On the HS carb the spring on the "bottom" is used as part of the jet adjustment. Don't mess with this unless you want to change your car's tuning. Adjusting carbs isn't hard but it does require patience if you don't have meters. There is also a spring inside the carb that is used to resist the upward motion of the carb piston that lifts the needle. Under no circumstances should you mess with this spring apart from cleaning it. You won't know that spring is even there unless you take your carb apart.

EDIT: As for the oil level.... If you over filled it then drove the car for a while, you should be able to remove the dashpot and see the oil about 3/8" [10mm] down the inside of the tube. If its below this you should top it up again.