Fuel leaking from nozzle air bleed hole

[Merryknees]

Hi Guys
I am a complete novice to Enderle fuel injection and have a problem which I hope you can advise me on
After shutting the fuel off the motor shuts down as expected but methanol runs out of the air bleed hole on the injector nozzles. I have cleaned and checked for blockages in the injectors [all clear] and stripped the check valve which again is clean and functioning. It's a 2-3 psi as recommended by Good vibes.
I have not been able to check the leakdown As I am waiting on a tester arriving.

Topolino build by Ian Merryweather, on Flickr

[dreracecar]

Does the fuel come out after the run during shut down or at from idle in the pits?? Plumbing looks correct however the vent in the cap (if thats all you are using) is too small for blown alch. and should be 1/2"

[Merryknees]

Only leaks when the engine stops after it has shutdown in the pits. There is an air pressure type hissing noise for a short while after the engine stops which corresponds with the fuel expelled from the air bleed holes. Fuel cap is the only vent I am using.
Car only has 2 runs on it as yet.

[ricardo1967]

Good looking mill!

[dreracecar]

Are you shutting down the engine by pulling the fuel "shut-off" and letting the engine starve and run out of fuel before hitting the mag switch??? or are you killing the engine with just the magneto???

 You will have to change the vent system to at least a -8 line for blown alc, that little vent in the cap is way way too small

[Merryknees]

Yeah shutting down by pulling the fuel shut off. I have ordered a tip over valve and fittings to sort venting issue you pointed out.

[dreracecar]

Very strange that you would still have pressure in the lines to expell fuel from the air bleeds.
turning off the valve directs fuel back to tank, engine now pulls fuel via the vacuum of the blower to drain the top lines and distirbution block, so there is no positive pressure left in the system to push fuel back thru the AB's. Is the secondary idle check going the right direction (point of the poppet should be pointed up)?? and if you can, fire it up again but leave the fuel cap off the tank and see if it does the same or different.

[Merryknees]

Thanks for the advise Dreracecar.
I plan to pull the blue blanking plug out of the top of the tank and run an AN8 hose line from there to the rear of the car. Could you please advise the best way to do this. ie loops, height out of tank.
My plan was to come up from the tank then down to the lower chassis rail using s/steel hose, then connect to ali pipeline following the lower rail up to the rear of the car and out. The reason being I only have a some amount of AN8 s/steel hose.
Can you advise what I should do/use to prevent fuel entering the line and how should I cap the open end at the rear.

Your advise would be much appreciated as I am away to our first meeting with the car this weekend and only have a short time to modify the set up.
I live on the Isle of Man so we're on the first ferry over to the UK mainland Friday morning.

Hopefully the breather setup is where the problem lies however if not there will be plenty of racers who I am sure will lend a hand at the track

https://www.flickr.com/photos/86222253@N00/

[dreracecar]

simular deal except that an extra fitting was welded to the tank when new. Drill and tap the cap for a straight NPT to AN-8 and either bend a hard line or use a hose end and line and go straight down with it. Would not worry about tip-overs or going to the back of the frame with your deal--- 99% of the racecars out there just have a line out in the open when running alcohol, gas is a different issue when its a door car with the tank in the trunk---keep it simple

[Draw 3D]

Are you getting a small weep from the nozzles after the motor dies or are you getting a stream?


Mine weeps a couple of drops or so and that's because the amount it weeps was not enough to keep the motor running so it weeps out. A quick test would be to have someone feed the motor with the squirt bottle for a few seconds after you shut off the fuel. The motor should scavenge the remaining fuel in the lines so there shouldn't be any weeping afterwards.


Good luck

[Merryknees]

dreracecar, I checked all the fuel lines and pump operation last night, all found to be OK. As a test I blew into the tank through the cap breather which has a small tip over valve in there. When the tank pressure was positive, pressure was trying to escape from wherever it could. In this case with no fuel in the system the air was coming out of the AB's on the nozzles. Thinking about it if positive pressure builds in the tank the idle check will not be able to open either.
Can't understand how positive pressure would come about but hey, will sort the breather first and see.
I haven't had time to run the motor up without the cap installed yet but to be honest our trip is paid for so going to do the mods here at home then test in the pits and track
Looking at your pic the breather appears to just loop out of the tank and point down to the ground, is that correct?

Draw 3D, more than a weep. Fuel runs out for approx 4-5 seconds on two to three nozzles and you can here pressure escaping whilst the fuel is running out.

Thanks guys

[Paul New]

I had a flapper valve vent on my last tank and in the sun the tank would actually build pressure and if the fuel shutoff is in the open position it would actually put fuel into the engine.
If you pull your shutoff and the engine revs up a little and dies without t kilometers by the mag does it still drip for 4-5 seconds? My question than is, have you verified your fuel shutoff goes all the way closed?

[dreracecar]

Yes it does, Off the rear tank mount bolt I have a tab that holds the other end of the breather hose. Since the hose opening is below the tank, if the car gets turned over the fuel level is below the hose end, and on its side the vacuum lock because of lack of any other vent will keep fuel spillage to a very minimum and that is why any roll-over check valve in the system is not needed

[Merryknees]

Latest, fitted an AN8 tank vent and ran the motor, still dribbling much like myself at the moment 
Motor sounding good, shut fuel off and the motor picked up as it run out of fuel, kept gas bottle at 45deg to centre butterfly, all shut down normally then fuel dribbling out of nozzle air bleeds for approx 4-5 seconds 
One thing that did not happen which was there before - the hissing/pressure release noise has gone, so the obvious answer it must have been the small tank vent sucking air in.
So now venting good thanks dreracecar.
But still dribbling

[dreracecar]

OK lets ask this now--- the air bleed holes on the nozzle bodies are pointed up? or are they pointed down?
they should be pointed up and any residual fuel from the nozzles tiny hole would seek the path of least resistence thru the large hole down lenght of the nozzle body and not to the top of nozzle hex.

 Dont care for the vent placement as you have it, since it is below the highest part of the tank and on the back side, with a full tank under hard acceleration , fuel climbing the back of the tank will seek and find the vent line and exit the tank, with the fitting in the cap or a seperate (new fitting) at the top of the tank, fuel climbing the tank will not affect the venting