fixed leaky fuel injectors
Elder User
Joined: Dec 2006
Posts: 830
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From: Kitchener,Ontario,Canada
Originally Posted by xlt4wd90
Aeroman,
You have some great ideas. However, there are a couple of problems.
I don't know if there are laws covering this, but it is very dangerous to route pressurized gasoline into the cabin of a car. I would do it only for as long as it takes to see if the fuel pressure is maintained by the pump under the heaviest load and flow.
For the enthusiasts who must know what their fuel pressure is at all times, they get an isolated tubing setup made specifically for this purpose. The fuel pressure side pushes against a sealed diaphragm of some sort, which pushed against a second tube filled with antifreeze, which leads into the cabin and fed into a liquid pressure gauge. Most of the guys who have tried to set up this device found it very difficult, and very unreliable.
I would try something a little different if I wanted to monitor the pressure as a regular part of my instrumentation. I would find an adapter to attach one of those electrical oil pressure sensors onto the fuel rail fitting, run the sensor wire to an electrical oil pressure gauge in the cabin, and monitor it like oil pressure. Most oil pressure sensors have about 80 psi capacity, which is about twice as high as the normal pressure of an EFI fuel system, so there is little chance of the sensor rupturing.
I was also toying with the idea of putting a T fitting in the hose to connect the pressure gauge and the spray cleaner at the same time. Unfortunately, that plastic hose that came with the inflate-a-tire is starting to deteriorate from all that Berryman B12.
You have some great ideas. However, there are a couple of problems.
I don't know if there are laws covering this, but it is very dangerous to route pressurized gasoline into the cabin of a car. I would do it only for as long as it takes to see if the fuel pressure is maintained by the pump under the heaviest load and flow.
For the enthusiasts who must know what their fuel pressure is at all times, they get an isolated tubing setup made specifically for this purpose. The fuel pressure side pushes against a sealed diaphragm of some sort, which pushed against a second tube filled with antifreeze, which leads into the cabin and fed into a liquid pressure gauge. Most of the guys who have tried to set up this device found it very difficult, and very unreliable.
I would try something a little different if I wanted to monitor the pressure as a regular part of my instrumentation. I would find an adapter to attach one of those electrical oil pressure sensors onto the fuel rail fitting, run the sensor wire to an electrical oil pressure gauge in the cabin, and monitor it like oil pressure. Most oil pressure sensors have about 80 psi capacity, which is about twice as high as the normal pressure of an EFI fuel system, so there is little chance of the sensor rupturing.
I was also toying with the idea of putting a T fitting in the hose to connect the pressure gauge and the spray cleaner at the same time. Unfortunately, that plastic hose that came with the inflate-a-tire is starting to deteriorate from all that Berryman B12.
Yes , I agree, dont recommend feeding pressurised fuel line into the inside of the vehicle at all !!
Pablos idea sounds just the ticket!
Aeroman
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Joined: Sep 2003
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From: SoCal
I'm sure I'm not the first to think of using the oil pressure sensor to monitor fuel pressure. I don't have access to the kind of machining equipment needed to make the necessary fittings, or I would have made one by now. But I'm not sure why no one has ever talked about this in any of the auto rags here in the US. Liability or litigation problems?
Big disclaimer: DO NOT TRY THIS AT HOME, KIDS. Fuel spraying in the engine compartment can be just as dangerous as in the cabin; there are lots of hot parts that can more readily ignite it.
No, I would splice a T fitting into another part of the fuel rail, and install real pipe connections, instead of using the Schrader valve.
Big disclaimer: DO NOT TRY THIS AT HOME, KIDS. Fuel spraying in the engine compartment can be just as dangerous as in the cabin; there are lots of hot parts that can more readily ignite it.
No, I would splice a T fitting into another part of the fuel rail, and install real pipe connections, instead of using the Schrader valve.
Elder User
Joined: Dec 2006
Posts: 830
Likes: 0
From: Kitchener,Ontario,Canada
Fuel Pressure
Originally Posted by Pablo-UA
Some years ago I had leakage from Schrader valve. Fixed with valve replacement.
It is interesting to see, how fuel pressure variates on run. More gas, more pressure (pessure depends on MAP)
It is interesting to see, how fuel pressure variates on run. More gas, more pressure (pessure depends on MAP)
Really? I had it in mind that pressure would be maintained almost constant with the pressure return system valve at about 40 PSI (whats that called?). With the mixture of gas/air being controlled by injector pulse time lenght verses air flow measured from the MAF or MAP.
Aeroman
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Joined: Nov 2004
Posts: 4,901
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From: Salt Lake City, Utah
Have you ever noticed that that fuel pressure regulator is connected to a vacuum line? The pressure it regulates at is inversely proportional to the engine vacuum so as vacuum drops, as it does under WOT or under heavy load, the fuel pressure to the injectors increases.
