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K-Jet Experts - please help (latest update Pg 6!!)

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Tried to fire up the car there after 6 years of restoration. It’s a 1983 tin top GTi with original DX engine. Car is turning over fine, but won’t fire.
1. checked for spark by pulling a plug and turning over and seems fine
2. pulled numbers 1& 2 injectors and I’m getting no fuel at all
3. cracked the 5th injector and I’m getting fuel there ok
4. I have fuel supply to the metering head
5. pulled the fuel distributor and the plunger is moving freely & looks like new (the distributor was not disturbed during resto, just removed as a complete unit for cleaning/painting).
6. I read a few posts on here that said the air flap might be sticking, just checked that & it’s super smooth & free moving.

I also seem to have a bit of fuel in the air filter. When I push in the plunger in the distributor I’m getting some fuel leaking out at the plunger, is this normal?

i guess my next step is to lift the flap manually while attempting to start to see if I get fuel at the injectors? If this works, what is wrong?

thanks in advance
Peter
 

Last edit: by Pistol

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Quick update, I jumpered across the fuel pump relay terminals to get pump running, and while manually lifting the air flap I got plenty of fuel flow from injectors.

Could this be an ignition related fault?  I'm wondering if I have a bad earth somewhere, as my VDO gauges are now going full scale when ignition live, and the indicators are not working and the green dash light is lit.  Hazards are clicking the relay, but only drivers rear is operating.  Teething troubles!!

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Rocker earth does the green light as does dodgy hazard switch... had to do this on Monday.

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spark amplifier maybe

Do not know a lot but willing to help if possible

1989 Sapphire Blue Mk1 Cabriolet KR
1985 Atlas Grey Mk2 GTI 2.0 ABF

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I'm getting a good spark when the engine turns over, but no fuel at the injector 1. Could the WUR control pressure be too high and preventing the plunger moving up to allow the fuel to pass to injectors on start up? It's an Audi 2.2 WUR to match the throttle body.

When I try to lift the airflow plate while cranking engine, the resistance is quite strong against the pressure pushing down on the plunger. It's not the plunger sticking cos that's freely moving & so is the air flap when the fuel pump isn't running.

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I bought a pressure test kit off eBay sometime ago, it was sold as a K-jet test kit but it only has banjo fittings on the ends to connect into the return line from the WUR to the fuel distributor, rather than the supply line from distributor to WUR. Anyway, with the fuel pump running by linking across the relay, and the valve closed, I'm getting 3 bar coming back from WUR. This might not be accurate as the banjo was leaking so had to abort test.

It seems a pressure test kit specific to K-jet is not readily available in the UK, but would something like this work? I've just realised it doesn't have a valve, and may not have long enough hose.
https://www.ebay.co.uk/itm/303469743242?_trksid=p2047675.m570.l5998&_trkparms=gh1g%3DI303469743242.N35.S2.typeBID_ITEM_ENDING_SOON.R1.TR3

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no point buying a pressure kit if you have no fuel
would still fire or attempt of the cold start injector
surely

Do not know a lot but willing to help if possible

1989 Sapphire Blue Mk1 Cabriolet KR
1985 Atlas Grey Mk2 GTI 2.0 ABF

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That's a bummer Pete! Just when you think you are there.
Watched this the other day, pretty decent vid on pressure testing k-jet K-Jet Fuel Pressure Testing - YouTube
Looks like he made his own tester. Can't tell if the one on ebay will have the right bits, but for 20 quid it's worth a punt even if you then have to buy a couple of the correct adaptors.
I'm not sure what the right system and control pressures are for a different WUR or whether you are supposed to set them to std (for a dx) as they will be wrong on that WUR. Do you still have the original WUR? You could swap that in to see if that solves the problem. At least then you know the culprit.
I'll think on and see if I come up with any better ideas.

J

My rebuild thread I will try and keep up to date: here

K-Jet fuel pressure test guage How-To

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It's a while since I did any work om the Mk1 but I'm fairly sure that if your pressure gauge is in the return  with the gauge on the WUR side of the closed tap then you are reading system pressure and 3 bar is low, from memory that is not high enough to open the injectors.
I've got a gauge that a local hydraulic workshop made up, the ends are not metric and not a perfect fit but it does the job, I'll take a picture later on.

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Cheers for all the advice so far. I am going to stick the original WUR back on and see if I can at least get her started, then once I have the proper pressure test kit I can see what's going on as the Audi WUR is adjustable & I have read about people needing to reduce the control pressure to get them running. Fingers crossed.

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Pete,
did a search and stumbled across this:
"If your system pressure is low - or if your WUR isn't working properly, it won't run right. On mine, the WUR was completely blocked, so the control pressure was the same as the system pressure - 4.5 bar of pressure pushing down on the plunger, which makes it harder for the plunger to lift and let fuel to the injectors. "

Good way to search the forum is to use goggle like so:
site:vwgolfmk1.org.uk control pressure

I've noticed that rubjonny (aka John Newman) has some useful doc's in his collection - he has a link in his signature.

Good luck!

My rebuild thread I will try and keep up to date: here

K-Jet fuel pressure test guage How-To

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Something else although this won't prevent it starting, if your Audi WUR has full throttle enrichment you must connect the vacuum pipe.
Sorry if this is stating the obvious.

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OK so a bit more progress.  Looks like I might have an issue with the thermo time switch as I'm getting fuel to the 5th injector banjo but when I crank the engine there is no fuel spray from the injector (with the injector removed and directed into a container while I crank engine over).  I believe I should have 12V across the TTS plug terminals for 3-10 seconds during cranking, but I have nothing.  Haynes says this points to a faulty fuel pump relay?  Since re-connecting the battery I do have a few minor electrical gremlins, and I'm starting to wonder if this all linked.  My VDO gauges are going full scale on ignition live, and the front indicators are not working at all (rears operated but at high speed), same for hazard lights which operated the flasher on the rears only.  Could any of these electrical problems be linked to not starting?  I can certainly hear the fuel pump priming on ignition live.

And I put the original WUR back on, but still not starting.  Everything else is original apart from the throttle body itself and the uprated cylinder head, so I'm a bit stumped.

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Most faults are simple, it's finding them.
 If you can connect your pressure tester as before but with no leaks and the gauge is on the WUR side of the tap you can read system pressure with the tap closed, if you only have 3 bar that will be your problem or part of it
From memory the four main injectors need about 3.5 bar to open.
 

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It's not the TTS after all, found another post from Rubjonny and when I connect between red/black wire & ground while cranking I'm getting voltage. But the CSV is still not delivering any fuel, so I'm back to fuel pressure testing so will wait til I get correct kit together. I also wondered if it was fuel pump relay but frigged across the terminals to make pump run continuously and it still wouldn't start.

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Just thinking ahead of myself, if it turns out my supply pressure or system pressure is low, what would be the cause if everything is as new.

New Bosch 0580464126 5bar fuel pump
New Crazyquiffs flexi fuel lines
Injectors ultrasonic cleaned and bench tested
New HEL braided injection lines
Airflow metering head assembly has not been touched apart  from cosmetically
New Bosch fuel filter
Fuel tank internals are spotless, new fuel used from a new fuel container.



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If it's supply pressure, then it could only be something before the metering head - so not the HEL lines or the injectors.
No kinks in the fuel lines?
How long has the metering head been sat? Not sure if they can gum up, but I'd figure that because injectors can, so could the metering head.
You can remove the plunger from the metering head without disturbing the magic inside, but as you say that is moving freely, I'm not sure if you'd see anything untoward.

My rebuild thread I will try and keep up to date: here

K-Jet fuel pressure test guage How-To

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There's a pressure regulator in the metering head, you could take that out and clean it and make sure it's moving freely, if it's not seating properly that could be your trouble.

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cedar said


I've just spent 10 mins looking at shiny parts that I want (but may not need!).

My rebuild thread I will try and keep up to date: here

K-Jet fuel pressure test guage How-To
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