will it start first time?

Know how you feel AL. took mine off at leat 3 times yesterday. I'm pretty much certain that's the problem with mine (fingers crossed)..

would like to give some advice with your problem but haven't got the experience with VW engines yet  ops:

you getting the right amount of fuel to the injectors? (Stab in the dark  :wink: )

Phill, looked into replacement metering head cost for my 1.6. Bosch service centre said they could recon mine for about ?170, Eurocar Parts said they did one for ?350 plus mine in exchange 8O  - didn't check VW. Is a breaker near Chelmsford doing 1.8 ones for ?40. Seems quite expensive to replace, not sure if a 1800 one willl work on a 1600 engine - different parts codes?

You may already have a copy, but I have a Bosch fuel injection manual which I could e-mail you. Much better than the Haynes. The valve on the side governs the fuel pressure in the metering head, not sure how easy to remove and refit without effecting set-up. Have you checked the sensor plate set-up, gapping and movement?

Are you using Prowlers injector test method to test fuel flow? If not how are you checking the system?

Cheers

I am going to do a flow test - possibly tonight…
Will also give me a chance to properly check the spray patterns.

Can someone tell me…
How much fuel should I get (from the injectors, not directly from the pump) and over how long (litres/minutes???)

markwon said

not sure if a 1800 one willl work on a 1600 engine - different parts codes?

They are different Part No's. I checked while looking for another to try on mine.
Mk1 1.8 and Mk2 1.8 8valves are the same however…

AL.

Hi Al, would have thought no probs with metering head if you have swappped it 8 times - unless all are dodgy :? . Use Prowlers injector test method. Not sure about how much you should expect as this is down to where you hold the sensor plate. Perhaps Prowler can confirm? When carrying out the test you should move the sensor plate back and forth through its travel looking for flats sport or inconsistent fuelling form the injectors. There should be smooth, progressive delivery as plate is lifted

From my own experience and reading ChrisB posts you really need a pressure testing kit to properly test compenants such as the metering head, unless you can swap over with ones you know definetly work.

Cheers

markwon said

When carrying out the test you should move the sensor plate back and forth through its travel looking for flats sport or inconsistent fuelling form the injectors.

Ah right - will do then…

As for swapping the metering head - I haven't actuall tried 8 on the car LOL… I have just had 3 on and off (Cleaning etc) a lot!!!!

Forgot to mention - apparent metering head problems may not mean anything wrong with the metering head. Its movement is governed by the below sensor plate, and sticky or incorrectly set up plate can be the culprit, bear in mind in operatoin the plate has to be free moving enough to be lifted by engine induction.

Cheers

markwon said

sticky or incorrectly set up plate can be the culprit, bear in mind in operatoin the plate has to be free moving enough to be lifted by engine induction.

Plate is free moving and nice and clean too!

in total I managed to get a VERY slow trickle of fuel from the injector fuel line (took no.1 injector line off the top of the injector inself)

this is all getting quite complicated and possibly expensive!

not sure on how much fuel over what time but as Markwon's suggested Prowlers test shows that when one injector reaches 100ml of fuel, the others should be AT LEAST 85, I think it would take about a year to get that much fuel through my injectors at the moment  :cry:

Oh I forgot to Mention Markwon… HOW MUCH!!  8O

think I'll see if I can get my mates off him for nothing as a spare and try to fix mine!

Can't say exactly, but from my testing would have thought injectors would take 20 secs or so to produce 100ml each. So yours aren't good (the output you quote is with the sensor plate fully lifted?). Unlikely, but just to confirm - have you tried adjusting the mixture screw between the metering head and sensorplate (clockwise to richen)?

Apologies if you have already done this, but have you checked the delivery rate from the fuel pump by disconnecting at the fuel filter and measuring output into a bucket over 30 secs? If all ok, then metering head is failing to pressurise properly. This might not mean the heads damaged, but possibly the main valve has been messed up by removal and needs setting up again? To do this you need a pressure testing kit - ?40 from the USA.

Probably stating the obvious here :roll: quickest and easiest way to eliminate metering head is to swap for one you know will work.

Cheers

I didn't try lifting the sensor plate manually, just put it all back together after checking the 0.10mm gap all around it.

there's definately good pressure (not sure on the delivery rate though) from the fuel supply before and after the filter, to and from the warm up regulator, to the 5th injector and to the fuel return pipe.

haven't touched the mixture screw either  :?

when you say the main valve do you mean the one at the bottom of the metering head? this did have a stiff point so i stripped it out, cleaned it with new fuel and replaced it which done the trick until I tried firing the car up where it went stiff again!

Is there some sort of small valve on each of the outlets to the injectors? I get no pressure on the outlet to injector 1, and very little pressure on the rest

If any of that makes sense!

The plunger in the middle of the metering head is the valve that controls the fuel to the injectors.

Do prowlers injector test manually lifting the air flap - If fuel now comes out of the injectors (assuming injectors are not blocked) then the plunger is sticking not allowing the air flap to rise.  If it still no fuel from injectors it is likely the metering head is gummed up and the orifices are blocked.  Only way to sort is to dismantle and clean or replace!

Underneath the allen head bolts next to each outlet there is a kind of valve, though as has already been said, I don't think you should be touching these.

FYI…
I looked at them on mine. I totally removed one of them and then realised "What if it wasn't all of the way in in the first place - I won't know how far to screw it back…"
On checking the rest, they were all 2 and a quarter turns out from the fully seated position.

good idea there, I'll see if manually lifting it lets fuel through.

i did take one of the allen key caps off (the rest where on so tight I couldn't move them) but didn't touch the one inside it

If that doesn't work I'll strip it all down, clean and see if it's fixed it.. hopefully my mate's going to dig out his tonight for me.. can't let things like that go to waste  :wink:

Bosch manual refers to the four valves as 'differential pressure valves' and control the pressure for each injector. Doesn't say if they are adjustable - you would need a fuel injection pressure gauge to make any adjusment anyway.

Best way to test the system is follow Prowlers method. Without lifting the sensor plate you can't really assess fuel delivery. Is also best and safest to test without engine running and with switch wired into fusebox. Makes testing a lot easier and safer 8O .

Cheers

If this helps anyone, I can confirm that I've used a 1.6 head on a DX (1.8 ) engine without problems, and set it up without doing anything to the settings other than setting the CO (mixture) with a Gunson's CO meter.

The nature of the K-Jetronic system is such that a healthy VW-intended system will work on almost any engine size from 1.5 to about 2.1 litres, because the amount of air flowing in (and the resulting porportion of fuel that is delivered) is directly dependent on the capacity of the engine, so the system is fairly self-adjusting…

Well, 2 cigarette's and a cup of tea later I now have another metering unit    I'll put this one this afternoon and see if it fixes the problem..

Is there any Bosch specialist's or the like I could take the original to to get repaired? going by the prices a new unit is it would be good to have a good spare.

I'll let you know how it goes

Phill, my local Bosch agent quoted rebuilds at around ?170. Should be able to find your local agent here' . Found mine to be very good, some Bosch parts cheaper than at GSF or ECP, plus they have the know-how. Also did a bag of copper washers (80+) to do the fuel injection componants twice over for ?3. At Halfruads you might get 10 mismatched washers for that :roll:

Cheers

Ah.. cheers for that Markwon, not sure I'm willing to part with that much just yet to have a working spare (know one day I'll regret saying that!)

lets just hope it solves the problem this afternoon!