Fueling issue

Hi all, 

Apologies for re-posting this, I posted the issue in General a few days ago but I have a theory id like to ask opinions…

I'm having a fuelling issue after cleaning my fuel tank out, I have cleaned the gauze filter in the tank and the tank itself, which was full of gunk.

When I start the car now it runs for approx 1 min the struggles for fuel, splutters and stops..

if I leave it for  2 mins switched off, then Re start, it will repeat the above.

I was thinking if this could be a blocked fuel filter, basically the pressurised side of the filter is pushing fuel through at a reduced rate when the car is switched off, and fills the lines which will allow it to run for the 1 min.. Then when the fuel is demanded, it can't pass enough through.

Filter was changed not so long ago, but not since the tank clean.

Thanks in advance

Mike.

What car do you have, fuel injection or carb and what year is it?

Sorry, my bad…

It's a 1982 1.8 gti cabriolet with fuel injection.

Has a strapped tank if that makes any difference? 

Mike

I would stick a new fuel filter on just to be sure, there is also a little gauze on the fuel pump.
I guess you just have the main fuel pump underneath the car and not a lift pump inside the fuel tank?

Why did you have to clean the fuel tank out?
Was the car standing for a long time or was it a rusty fuel filler neck?

I cleaned the tank as when under 1/2 a tank, it would cut out on corners and kangaroo with any movement of fuel in the tank.

There was a lot of seddement in the tank underneath the gauze filter inside the tank, I managed to get most of it out by pumping and a magnet, I suspect it was the rusty filler neck, which was replaced a few months ago.

The accumulator and the gauze filter in the pump were cleaned to no avail..

Mike

Try a new filter then if no better you may have to look into cleaning out fuel lines, meter head and injectors.
There is a guide in the Haynes manual on checking the injectors spray pattern and measuring the amount of fuel which should come out.
There is also a thread in the fuel section on testing the injections which may be helpful.

Thankyou for the advice.

I'll order a new filter in the morning.

My theory on why it may be the filter as the car runs fine for a minute or so on startup, if it was a blocked metering head / injectors would the performance be bad all the time?

Mike

It may be it's running on the 5th injector as that spray extra fuel in on start up, if you unplug it (remove the electrical connector) you may find it won''t run at all?
5th injector on the side of the inlet manifold.

so this morning i looked into the 5th injector, unplugged and the car worked fine…

I've also checked the injectors and they are all outputting..

replaced the fuel filter, to no avail…. still the car runs one for a minute or 2 then cuts out spluttering…

its very frustrating..

who said owning an old car would be fun

when you checked for fuel at the injectors, did they only spray when flap lifted and not at rest?

I've experienced something similar with my 1989 GTi with "K" …. Adjusting the slow running (air) screw on the back of the plenum chamber. The car would do exactly as you've described, starting immediately from cold then sputtering to a stall … Starting on the extra air valve then as it closed … it would stall. I also discovered the air flap sticking inside the metering unit. Did you know you can loosen the securing bolt for the flap, turn the flap and "adjust" its position ? I do, now …..

Ok Ok since my last posting on here I've finally got to the "bottom" of my fueling problem and I suspect if the original "poster" tries this tip he may well have a cure too.

I fitted a new fuel filter too, this improved matters slightly, for a while …. But some times the little "cursed car"  just WOULDN'T start no WAY …. From hot or warming up. Narrowed down to certain fueling issues (low pressure ?)

IF I left the car to "cool down" maybe 20 minutes this recent hot weather it would fire immediately … If I could get it back to operating temperature with out stalling I'd be fine for the rest of the journey.

Sometimes I'd start the car from cold and leave it running "just to see" … It would fire instantly settling down to a fast idle (whilst the extra air valve was operating) then as the valve closed the engine began to "hunt" just like my old Escort used to do on a winters morning if I'd left the choke out. Though this was in my instance because of not enough fuel instead of too much. If it stalled during warm up it wouldn't restart until the engine cooled again …..

To cut a very very long story short I have now "adjusted" the "warm up regulator" how to do that is all over the internet … With no pressure gauge I was a little concerned, but with a sick car I thought I'd be really very unlucky to make it WORSE. I started the engine and began listening for the onset of the "hunting" (rough running) miraculously within a few seconds I'd transformed the engine note completely.

Switching off and re-starting is a cinch (just how it should be) and on the road …. ITS A DIFFERENT Car performance is now neck jerking …. ALL DONE WITH A HAMMER ! Regards to the Forum