K-jet metering head strip down and rebuild thread

Fuel hose swap will narrow the search down too All worth a look at. I will look at checking the air flap height to ensure it pushes on the centre pin to shut off fuel.
Watch this space

 

Had another go this morning. Swapped the hoses over and still nothing coming out of no2 distributor port. Atleast that points to the main unit. I even removed the filter but this made no difference, so off the car it will come.
What confuses me is I thought there would be no fuel spraying with the air flap closed, so i was expecting to control that by lifting the flap..
Although more thinking has me realising that fuel has to flow for the engine to run at tick over with the air flap closed. Does that sound understandable.? It messed with my head that I have the ignition lights on and it works due to doing the relay swap, when in reality it won't work like that!!....
Anyway, time to take this apart and see what I have done wrong

 

Stripped the regulator down, quick rebuild and I had no flow.... realised that the centre pin notch was 180° out and I had a slight weep.
Quick stripdown again with a thorough and methodical clean and seal then refit. I also adjusted the CO Allen screw to drop the air plate.
Power on, and no fuel flowing.....lifted the airplate and I have fuel out of 4 injectors, nice conical spray pattern, result.
So I spent another hour faffing to try and get the quantities roughly the same for now. I really need a cc measuring jar to pour them into and compare, but that can wait. Now we have fuel I need to test the actual system pressure and then fine tune the flow I think
No weepage from the injectors afterwards
What a day. And relax
Have I missed anything?

 

Excellent work... going to have to get you to explain 'the centre pin notch was 180° out' in more detail, sounds like something I'll have to be aware of when the time comes.

Again, great stuff!

 

For what it's worth, the German VAG Workshop manual for the KR suggests testing the cold enrichment valve as follows:

"CHECK PRESSURE JUMP SWITCH

Disconnect the plug from the pressure jump switch (F39)
Start the engine and let it idle.
- Measure resistance between contacts. Set value : resistance should measure infinity
- Increase engine speed by quickly opening the throttle valve. Resistance must drop momentarily and then rise again to infinity."

It was translated using Google Translate so the language structure isn't perfect, but you get the idea.

 

Thought I would add to this as I am about ready to start the car.
Checking the flow rates needs a specific VW tool to hold open the air flap to simulate idle and then full throttle. And I can't find this anywhere so have had to best guess.
The fuel distributor really is adjustable in getting massive flow rates, so I have tried to set it as the Bentley states
80ml in 40 secs max 8ml difference FULL THROTTLE
20ml in 2 mins max 2ml difference IDLE
I've managed to get 81,81,81,80 so happy with full throttle
Yet 18,18,18,12 at my idle guess
So as you see, injector 4 is considerably lower. Yet when I turn this up it massively affects the full throttle. For now I shall see how it goes. Reading what others have done and everyone seems to have measured full throttle, but nobody seems to mention their idle readings for me to check against.
I intend on checking the fuel pressure so need to sort making this up. I'm sure it will run like a pig as the CO is going to need adjusting as well.
Any tips for where to set things are always appreciated

 

I have rebuilt many of these an flow tested more, idle is hard to get right from experience, the metering heads will flow 200+ cc/min if required, my own 16v is at 195cc/min currently.

On the flip side the more you add at max the more you get at idle which then plays havoc when setting idle CO%

Also I have yet to find any difference internally with the metering heads be that 16v, 8v, Volvo, Porker etc

The only difference found is the Mk1 1.6 metering head but that is only different in the way of the fuel pin centre portion being a different size thus letting more fuel.

All body's I've seen all have identical 0.2mm wide slits also.

 

Also for C02% I have a gunson tester but to be fair it's not the best and can be accurate vs mot tester or wildly off. I use wide band LC-2 as it's more accurate.

Here is a C02% - AFR conversation chart

 

How did you get them out. I'm going to replace mine and any tips gratefully received

 

Carefully!

... and this (Size M5).

 

Top tip, thanks. How are your cars doing?

 

Probably going to SORN them at the end of the month, started out well in the Spring / Summer, put quite a few miles on them both, but not been out in 6-8 weeks what with one thing then another.

MK1 turned 40 last week-end, no more MOT's to have to aim for or work around.

Trouble is it's still a shell plus dozens of boxes of bits so that's not much use to me at the moment, it also becomes tax exempt in April next year... pretty confident it'll be moving under its own steam by then.

Engine etc. is back and built (read that as mocked) up, couple of elusive bits we need to get it 100%, then hopefully I'll be picking your brains when it inevitably won't play ball.

 

My bad... it's M4.

 

A quick update in that I had sent my broken unit off to KMI. 16 weeks later ( earlier than promised) it has returned and looks great.
I had just had enough of messing with it. I shall post up how it runs when fitted.