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I adjusted the AF screw to full lean (CCW until a firm stop), and the fuel injectors still fire when I run system pressure (measured between the WUR and center of fuel dizzy) to 60 psi. Pressure holds well afterwards, but peaks at 60psi. Is something wrong with my fuel distributor?
I adjusted the AF screw to full lean (CCW until a firm stop), and the fuel injectors still fire when I run system pressure (measured between the WUR and center of fuel dizzy) to 60 psi. Pressure holds well afterwards, but peaks at 60psi. Is something wrong with my fuel distributor?
your FD plunger might be stuck “up” .. with no fuel pressure it should fall by gravity. With fuel pressure it should be held down against the sensor plate. There should be no slack, when pushing down the sensor plate, between the sensor plate and the plunger. I had one do this to me today .. the plunger was hanging up a little causing injector flow.
you'll want to change your oil if the injectors have been spraying without the engine running.
The gauge pressure increases when I push down on the air flow paddle, and there’s no apparent free travel in the movement of the paddle. So, I think the plunger is moving smoothly.
Could I have created a leak path in the FD allowing fuel to flow too easily?
Or, since this issue came up after I split the air guide to replace the gasket, maybe something is wrong with the AF adjuster. How can I check the air guide assembly for proper adjustment?
This video shows pressure rising with the fuel pump after sitting overnight. The engine is off and I'm using a jumper switch. You can hear the pump start, see fuel pressure rise, and then the injectors sing.
This video shows what happens when I press on the air flow paddle with fuel control pressure present. The gauge pressure pumps up with the fuel gauge valve open, but doesn't shift with the valve closed. The valve is between the gauge and the FD.
This video shows what happens when I press on the air flow paddle with fuel control pressure present. The gauge pressure pumps up with the fuel gauge valve open, but doesn't shift with the valve closed. The valve is between the gauge and the FD.
The valve on the gauge is supposed to be between the gauge and the WUR. When you close the valve you are eliminating the WUR control pressure circuit, the gauge shows system pressure with the valve closed, and control pressure with the valve open. With the gauge valve in the wrong place the readings will be kind of kooky.
I moved the ball valve to between the WUR and gauge, and got up to 68psi with the valve open and with it closed. The injectors were blowing off any time the pressure got above 40psi.
I moved the ball valve to between the WUR and gauge, and got up to 68psi with the valve open and with it closed. The injectors were blowing off any time the pressure got above 40psi.
I think there’s an issue with my FD.
Who rebuilt your stuff?
There's a multitude of issues:
No pressure changes usually means your WUR circuit is completely blocked. When the gauge valve is open it allows the WUR circuit to lower system pressure supplied to it down to the control pressure required to counter-balence the action of the plunger.
I know you mentioned rebuilt WUR, but you also mentioned dirt in the system.. this is all it takes. The WUR typically WILL NOT pass dirt.. its usually the blockage point. Dirt in the rebuilt WUR will require it to be pulled apart. See this Ferrari write up it has good instructions: http://www.ferrari400parts.com/Warmu...atorrepair.php
The injectors spraying above 40 PSI system pressure is FD or sensor plate related.
drooman, I rebuilt everything myself. I'll dig back into the WUR again after I get my FD fixed up again, but I did verify that it is not clogged when I took it apart again a few weeks ago. Thanks for the link to the hard lines, and I'll double check those later this week too.
I removed the FD tonight and found that three of the 8 rubber rings on the tube with the circular filter were damaged. One was completely cut through with a small piece dislodged and free to move around. I found all of the rubber pieces, but need to buy new o-rings now. That should explain why I was hearing injectors blow down, and also why I thought I only heard a few blowing down. After I get the FD fixed back up I'll do another pressure test. Does anyone know where I can source those o-rings without buying a full rebuild kit? FYI, I've had that FD apart a few times, and this is the first time I've torn those rings. I found a good trick on how to hold them in place with a rubber band (or similar) while installing, so I'll do that next time.
Also, do I need to replace the orange ring in one of the attached pics? I don't remember getting a replacement for it in the Salvox kit I got.
You demonstrate the persistence required to sort these systems! The split o-rings can also allow system pressure to cross into the control pressure side of the system. The new o-rings may resolve your lack of any control pressure action as well.
If you don’t have one already, get this book...best technical and operational theory explainations of the system available:
Be careful testing the system. When you can hear your injectors you have fuel going into the cylinders, which will leak down into the crankcase. At minimum you will want to change your oil before you run it much. If you have a silicon pan gasket you will want to be even more careful as fuel in the oil we eat the silicon.
For future reference I think I got my o-rings from McMaster. Make sure to get viton.
12-29-2018, 08:24 PM
Fuel injectors “sing” with AF full CCW
