Help 502 EFI stalls out
09-08-2014, 09:47 PM
#11
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Location: Rapid City SD
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Having been through this whole ordeal-
1) Check your mechanical pump for output pressure. Its port are 1/4" NPT so round up a 0-15psi gauge and see what it produces, it should be around 7psi IIRC.
If it does not have adequate flow or pressure it won't be able to keep the electric pump's sump full. http://www.northerntool.com/shop/too...FaY-Mgodzl0AJg
2) Next time it stalls remove the brass plug and see what happens. If it's vents a lot of pressure the mechanical pump may not be able to push fuel into the system. If it's empty I'd suspect the mechanical pump's foot was wearing to nothing, you'll know it when you see it. Carter/Airtex #60932 is a good replacement pump. http://www.offshoreonly.com/forums/d...fuel-pump.html
3) Check the fuel pressure at speed from the electric pump. Your local auto parts store should have everything you need for rent/free. You need 36-38 psi with the engine off idle. If your pump does not produce that, I'd look to replacing the regulator. http://www.cpperformance.com/p-13316...regulator.aspx
4) Look into the VST diaphragm issue, but I don't have any experience with that.
Eddie Young has a pretty good thread on here about helping to cure the vaporlock. In short, plug the VST return port and route the hose back to the fuel tank. You'll need some hose and fittings. The VST sump uses 5/8-18 inverted flare, and from there I'd use -6 push-on fittings back to the tank.
1) Check your mechanical pump for output pressure. Its port are 1/4" NPT so round up a 0-15psi gauge and see what it produces, it should be around 7psi IIRC.
If it does not have adequate flow or pressure it won't be able to keep the electric pump's sump full. http://www.northerntool.com/shop/too...FaY-Mgodzl0AJg
2) Next time it stalls remove the brass plug and see what happens. If it's vents a lot of pressure the mechanical pump may not be able to push fuel into the system. If it's empty I'd suspect the mechanical pump's foot was wearing to nothing, you'll know it when you see it. Carter/Airtex #60932 is a good replacement pump. http://www.offshoreonly.com/forums/d...fuel-pump.html
3) Check the fuel pressure at speed from the electric pump. Your local auto parts store should have everything you need for rent/free. You need 36-38 psi with the engine off idle. If your pump does not produce that, I'd look to replacing the regulator. http://www.cpperformance.com/p-13316...regulator.aspx
4) Look into the VST diaphragm issue, but I don't have any experience with that.
Eddie Young has a pretty good thread on here about helping to cure the vaporlock. In short, plug the VST return port and route the hose back to the fuel tank. You'll need some hose and fittings. The VST sump uses 5/8-18 inverted flare, and from there I'd use -6 push-on fittings back to the tank.
