Too much fuel

Hello although i've owned my golf gti (1983) for around 7 years its never actually made it onto the road, so I thought its about time it did!

But the problem i'm having at the moment is to much fuel entering the engine, so much infact it mixed with the engine oil. So I followed a test precedure I found on the site for testing the injectors. (using a switch from the fuseboard and the jars etc) and I've fould no matter where I have the flap on the air box fuel streams out of the injectors. Now the test says that with the fuel flap down no fuel should flow, so does this mean something is wrong with the metering head or does it point to something else. I did disconnect the return pipe but this made no difference.

Any help would be much appreciated.

Thanks Rob

does sound like the metering head is toast. take it off the air flapper assembly, there are 3 screws on the top. then underneath you'll see a pin, this should move in and out smoothly without binding, if its jkammed in place you will probably need a new one!  I have 2 MK1 metering heads that are like this

I have taken that off and the pin does seem to move freely.

I even operated the pin with my hand- holding it in and letting it push out to try and change the rate of fuel through the injectors. With no joy.
There was alot of pressure there enough to actually blow the pin out like a dart, and it was differcult to hold it in by hand. But I just thought this would be right as it does operate at pressure?

Thanks

yeah that is correct, fuel pressure will push it out if the pump is running. check the height of the air flap next, it should be level with the narrowest point in the cone if that makes sence?

Yeh the flap sits at the bottom of the cone.

I've now bought another metering head which will hopefully be with me soon. So it will either fix it or rule out the metering head

cool, if not the metering head the next place i would look is the warm up regulator on the front of the head, this is responsible for controlling the fuel delivery to the injectors.  My guess is the metering head has an internal blockage or a problem with the pressure relif valve causing the internal pressure to be too high.

Ideally you need access to a fuel pressure gauge this will help track down the cause of the fault if neither of the above help

Ok cheers i'll see how I get on with the new metering head.
I have swapped the warm up regulator with another one I have but this made no difference, but theres always a chance there both faulty? I looked on euro car parts site at the price  8O  why are they ?195!
How does the regulator actually adjust the fuel pressure?

The warm up regulator sets the control pressure, this acts upon the top of the lever in the metering head. So, a low pressure - air flap lifts more, more fuel is delivered to injectors. As the control pressure rises, this restricts the air flap from rising so much and also means less fuel is delivered for a given airflow.

It works by having an internal restrictor/valve which is acted upon by a bimetallic strip (applies a force which varies with temperature). The heat comes from the conduction from the block and a heating element and electrical connection.

what it does is regulate the fuel pressure in the top half of the metering head, above the pin.  This changes the force required to move the metering pin, which changes the angle of the air flap for any given volume of air being drawn in.  This changes the amount of fuel delivered for any given air volume drawn in by the engine.

The pressure at the top of the metering head actually increases as the engine warms up, which means it takes more force to lift the metering pin as the temperature increases. Therefore when cold the metering pin moves up further for any given air volume than it does when hot, hence making mixture richer when cold

inside the WUR is a bimetalic spring which reduces the amount of fuel allowed to flow thru the wur as it warms up from engine heat. there is also a heater inside it powered by a fuel pump feed, which makes it come 'off choke' quicker.  16v wur has an additional vacuum feed which allows it to control the mixture based on engine load as well as temperature.

I hope all that made sence  

ah bugger it, too slow. oh well!

Good news………..

Fitted the new metering head and had it running

awesome  8)