HOW TO: Set System & WUR fuel pressure

OK, to set your fuel pressure correctly, you will need a fuel pressure gauge with stop taps on it and a 6 mm metal drill bit and drill. - good place for the gauge setup is here -
https://www.glencoeltd.co.uk/catalogsearch/result/index/?cat=26&q=pressure+gauge

NOTE - This is not as accurate as having it set up by stealth or other professionals as you really need a rolling road to test it against as some cars may need slightly different pressures to find there best, but this is pretty accurate.

Also this the first draft, i will be adding more pics and info when i get them

Preparing the WUR

1) - First - disconnect the fuel unions going to the WUR (Warm Up Regulator), put an old towel below the WUR and use a small jug to catch any fuel, about a table spoon comes out!

2) - Then undo the WUR by the two allen key bolts, and remove!

3) - Then shake any excess fuel out of the WUR and leave upside down - fuel inlet and outlets down side on to a cloth to make sure all fuel is out, you can leave this for about half an hour to be sure.

4) - Then put the WUR on to a work bench and secure it, making sure the brass cap (back of the WUR) is facing upward. Then using your 6mm drill bit slowly drill into the centre of the brass cap, do this very slowly as it's not that thick, ideal you do not want to hit the hidden allen key on the other side.

5) - You should now see the allen key screw, make sure you can easily fit an allen key into it, but don't turn it yet! you can mark it with some tipex on the screw and the side of the WUR, as if it all goes wrong you know where it was to begin with.

6) - Re-attach the fuel lines to the WUR, but leave the WUR securing bolts off for now!

Fuel pressure gauge

1) - Connect the fuel pressure gauge up between the metering head supply to the WUR and the WUR line. Make sure all the connection are tight! and the shutoff valves are open.

2) - Now start the car (may take a few turns to get the fuel flowing again) and the pressure should start to rise on the gauge.

3) - Watch the the gauge rise, if your WUR is working it should steadily rise smoothly, no jumps! after about a minute/minute 20 secs it should stop rising - note the pressure.

4) - Now to see the system pressure - turn off the shut off valve closest to the WUR side. The pressure should rise further, once it has stop and the car is at full temp, this is your system pressure.

5) - Also check the fuel pump is getting the correct healthy supply of battery voltage! this can effect the system pressure!

Ideal system pressure is around 5 bar!

6) - If it is higher or lower you can adjust this by taking the shims out of the valve (see B below), I never needed to adjust mine, and i found it was impossible to get hold of different thickness shims, a scrap-yard would be your best bet.

A 0.5mm shim (depending on the spring condition) should give you .75 bar pressure increase.

A 0.1mm shim should give you about 0.15bar increase.

For shims M5 washers fit..if your desperate you can look through your spares for thick and thin ones....or sand em down to suit

7) - Now turn off the engine and keep an eye on the gauge, the pressure should not drop below 2 bar after 20 minutes, this indicates that your fuel accumulator is doing it's job and holding pressure.

8) - Once you have set the correct system pressure, re-open the shut off valve on the gauge, and the pressure will drop to give you the control pressure from the WUR, you are ideally looking for 3.4 bar (48psi).

9) - Now set the pressure by turning the allen key screw on the back of the WUR until you reach 3.4 bar.

10) - Now turn engine off and remove the gauge and tighten up all the connections.

11) - Then re-attach the WUR to the engine.

12) - As the control pressure has been changed, you now need to set the C0 (mixture) as this will be affected, follow this guide here - https://clubgti.com/forums/index.php?threads/124949/ or take it to an MOT testing station, chuck em a fiver and ask to put it on there gas machine and set it to 2% (red lead disconnected and breather pipe, air-box end removed and air-box blocked).


Job done

Credits:

Ade.Mk1 - for lending the gauge!
Gareth83 - for talking me through the set up!
Golden
philip walker
PaulM
Stu

If i missed anyone just shout

If anyone wants to add to this, just pm me and i'll add your bits or change anything! the more info we get in here the better for everyone!

 

can I have a mention?? pleeeese

 

Good stuff, I recognise that gauge, helped sort my car out too!

 

Just updated the credits anything i missed guyz?

 

don't think it was Ade.mk1 it was 150pdgti or something like that

 

Good thread mate, handy.

The link to my 16valvestall page will be dead, I need to get that page back on line.
Edited by: GVK

 

Gareth83 - he changed his user name


GVK - Thanks - oops, i never checked it! i can host the page if if you want?

 

make this a sticky

 

I can host it, it's just that I had that page hosted on BT but then stopped using the account, so all the stuff was lost ( including the pics ) [:^(]

I think the info is on here somewhere maybe in FAQs

 

I see no worries! I'll go and have a look

 

Would some kind mod stick this in the FAQ's please?

 

This thread would be better if the pictures worked

 

piccies still dont work.

 

well it is a year and a half old lol

 

thought id just add this with pics as ive just set mine,gotta do it again as ive replaced bits since then,

fuel pressure gauges { bosch-k-jet guages with all the right adapters}


fit adapter to one side of the guage


fit the other side of the guage { with no adapters} to the centre fuel metering head .



fit the adapter end to the fuel line u just took off,


hang guage vertical, and purge trapped air,


make sure gauge is open and start engine ,


this is control pressure,


close gauge,


this is ur system pressure,

mines 5.5 bar as i already added shim, gonna take it out weekend back to 5 bar.

drill slowly,light pressure { thin metal} to reveal allen screw. { drilled slightly to the left so had to open out with snips}


adjust make to 48psi


realease fuel pressure,

unscrew gauge and re fit fuel lines.

as u adjusted pressure u need to set co back to 2% , i used the handy co machine

 

I spent ages trying to find a source for a Bosch K-Jet gauge kit but I couldn't find anything. Where did you obtain yours from?


Edit: Oh hang on - think this is what you have, isn't it?

http://www.etoolcart.com/browseproducts/CIS-K-jet-Fuel-Injector-Tester-TA33865.HTML

 

yep thats the ones, from the states, the only place that i could find any, sealey do a kit for just the gauges at 200 then u have to buy the cis k-jet adapters for another 150. ouch

took 29 days to get here due to email communication, had to pay a futher 20 for extra delivery, plus 27 for customs duty, and in that was 11 for the company over on the island who deliverd from mainland held it untill i payed the 27 , { as they payed the duty} in total came to bout 150 but worth it as i can now tune the car and do all the k-jet tests, found out that my residue pressure dropped major when turned off, { hence hot start probs}

 

just make your own kit for about 30

good write up by the way!!

 

Care to elaborate gareth?

 

Also what engines can you do this on. I have a mk2 Modified 9A 16v and my mate has a standard 1.8 8v K-jet. Can i do this mod on both using the same settings?