GTi cabby fuel injectors and brake servo valve

Hi

Trying to get engine running right - my first issue was leaky fuel lines so they are now replaced and car now starts sometimes, but dies when try to rev.
Getting spark ok so guessing fuel is still the issue.

I bought car few months ago and she has been off the road for over 11 years so as a starter thinking of putting new injectors in as guessing old ones might be a bit gummed up. Plan to do spray pattern test once figure out exactly how to do it - is there a guide anyone? Read few posts about putting jumper wire in place of relay to power pump and manually moving the airflow plunger - is that all need to do?

There appears to be 2 types of Bosch injectors, the early one being 0437502047 and later ones 0437502032 so wondering if they are interchangeable as can get a set of 4 of the older ones for around £70. Later ones would be more than double that.
Classic-vw 0437502047 listing states ' Direct replacement for all M12 threaded K-jet injectors' which implies they are interchangeable.

Onto my other issue - when struggling to remove the old injectors I managed to break the small vacuum nipples off the brake servo check valve.
I'm struggling to find replacement online - mine has 2 inlets whereas ones online only have 1. Photo below - 2 small nipples missing as snapped off.
Anyone know the part number and suitable supplier?
Also struggling removing the valve from the hard plastic line to servo - any tips? Tried heat but no joy.

Thanks
John

You might try a mk3 check valve as the a/c delco one that I knew of is NLA.



You would probably have to cut the new ones pipes off to get it to fit… but I don't know the diameter of the hose connections.

pn for it should be 1H2612041N
https://www.volkswagen-classic-parts.de/udruckrohr-5ad02c.html

Thanks Brian that's similar to others I've seen but one on my car has 2 inlets as in one to servo and also tee off to left

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Photo shows 2 inlets

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Oh Automatic.

You can get that check valve, and place it in line.  Use a plug to plug off the spare port, and then insert a Barbed "T" fitting prior to the check valve to attach the Automatics Venturi to.

Yes a tee with that valve would work. You've lost me on automatic venturi. What's that?
I'm thinking of trying drilling out existing valve and bonding in short lengths of brake pipe to replace existing nipples

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The gray thing in the middle is the Kickdown Venturi for the Automatic.

Yep that's confused me as my car is a manual
Does that mean my engine setup is for an automatic?
If yes what other differences might there be?
And would I need to remove/ correct etc?

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Yes you could do away with that….
But you would need to Plug off the hoses.

It sounds as if your car had a engine/transmission swap
as I have only seen that on the Automatics, (I own 2), and not on my Manual Rabbits/Golf's or Cabriolets.

www.cabby-info.com has the routing of Vacuum hoses for the Auto, and non-auto cars, and would make getting the Vacuum Check valve easier.

Thanks Brian
I googled gti engine bays and ones I found seem to have same setup as mine and have clutch cables. So if disconnecting just plug the port? Just for my info what does the venturi do and any harm being connected on a manual?

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All UK cars from 1985 ish with K-jet fuel injection system has the same set up as you.  So don't worry about if your car was once an Auto and now a manual gearbox as I expect it was a manual as VW only sold a Auto box on a carb car and never on a GTi in the UK.

Briano1234 is from the USA and they seem to have a different set up over there, perhaps its to do with emissions as alot of cars over there are fitted with CATs.

The valve is no longer available, when you could buy it you bought the whole length from the brake servo to the valve, used to be about £15 for a new part as I broke a couple over the years so I'm on my 3rd pipe. I'm much more careful now removing the pipes!

You may need to look around scrap yards for a VAG car with a similar valve and somehow remove and refit the new valve. Try looking at Mk4 golfs I managed to find one from one, just cut the pipe either side of the valve and not attempted to remove it yet as it's just a spare till I break another pipe!

My set up on a 1988 Gti cabriolet, manual gearbox.
White pipe goes to the MFA to show your MPG, Yellow hose goes to a valve which enriches the mixture if you floor it when cold (never a good idea).




    

thanks Mark, that's re-assuring to hear - was wondering if poor running/hard to start was due to incorrect setup from prior owner.
Bought as a non-runner and no MOT since 2006, so bit blind on history on auto box etc. Tax book says manual though.
So to get running in mean time, I'm guessing can blank off the 2 broken ports. MPG display not bothered about and other I'm guessing not going to affect basic running of engine. Just checked and assuming its a vacuum switch, its open with no vacuum so assume leaving switch open with engine running not a major issue? Do you know how it enriches the mixture? Maybe powers cold start valve, although thought that was just purely for cold start?

 

Plug up the holes for now as the car will not like the air leaks, the car will run fine without those hoses connected untill you find a replacement valve.
Not sure how the enrichment valve works, it's next to the airbox so perhaps it does something with the metering head, early cars do not have this valve.

was curious - appears enrichment valve does enable cold start injector as believe the metering head is purely hydro mechanical (no electrics) - found old post:

https://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=electrics_2%2Faccellerator-enrichment

which states:
The throttle valve switch is for cold enrichment when first accelerating. The thermo time switch should work in line with the throttle switch and cold start vacuum switch so when you first accelerate when cold the 5th injector puts some fuel in also to help with the cold manifold and give a nice power level. only for 0.4 secs though. When the engine or thermo time switch is over 35 degrees the cold acceleration does not work as the thermo time switch goes to open circuit, stopping any 12v supply to the 5th injector.

Tried injector test earlier - no fuel from injectors with pump on and air flow plunger lifted
Cold start valve seeing enough pressure to allow bit of fuel into engine to start, but dies when times out.
Checked fuel pick pump in tank - its dead and both pressure and return hoses rotten/collapsed.
Main fuel pump making lots of noise as guessing being starved of fuel
Both pumps ordered along with filter and fingers crossed that will sort it as MOT booked for next Friday!

mk2 golf all have the same check valve as you, but replacing it is tricky the hard plastic is very tough to stretch.

have a read:
http://www.vwgolfmk2.co.uk/forum/viewtopic.php?f=37&t=25972

with fuel injectors you have coarse and fine thread, plus air shrouded and non-shrouded types.  they all flow the same, with yours being late you probably have the shrouding system on it with fine thread injectors.

if you end up with non-shrouded and your head is shrouded, block the nipple off on the back between injectors 3 & 4 else you end up with an air leak. alternatively if you're carful you can sometimes swap the top hats over from the old injectors, just make sure they are secure dont want em falling off.

other way round just pull the top hats off the new injectors and away you go.

you can swap between coarse and fine thread injectors if you get the fuel lines to match