Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: JamesHigdon on June 21, 2016, 17:35:31
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So I've been doing my due-diligence as a new member of the Pagoda world and have a question related to the cold start valve.
In http://www.sl113.org/wiki/Engine/ColdStartValve (http://www.sl113.org/wiki/Engine/ColdStartValve) it states The CSV is fed by a fuel line from the high pressure fuel pump.
in one section and Remove the small bolt (marked by the arrow in the component view photo) and turn on the ignition. There should be NO fuel leaking out with the fuel pump activated.
in another section which I take to mean the system is fed by the electric fuel pump as having the ignition turned to on obviously wouldn't activate the mechanical pump.
I can see the obvious fuel feed line running from the high-pressure pump to the CSV but does the electric fuel pump (as noted here http://www.sl113.org/wiki/Fuel/Pump (http://www.sl113.org/wiki/Fuel/Pump)) push fuel past the injection pump to drive the CSV even before the high pressure pump is running? If so THIS may explain my cold start issues as I don't get any CSV flow until the engine is spinning.
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If you look closely at the fuel line as it comes out of the fuel filter (the one at the front of the car) there is a tee. The line from the top of the tee goes over to the CSV, the other side of the tee goes into the injection pump. The fuel pump at the rear of the car is what supplies the fuel to the CSV, not the injection pump.
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To clarify your second screen grab the small plug is removed and IF the engine is warm there should be no flow with the key in the crank position. If the engine is cold and you turn the key to the crank position you should see flow for a few seconds. I Think the plug is between the solenoid and the nozzle so just because you have flow at the plug it does not mean it is reaching the inside if the intake as the nozzle may be clogged.
There are a bunch of things at work during a cold start but maybe you can narrow it down by doing the following in order:
Verify fuel pressure at the cold start valve or inlet of the Injection pump(Forward fitting) if memory serves it should be around 10 pounds.
Connect a test light across the cold start valve and see if the light glows for a few seconds then goes out when you turn the key to the crank position with the engine cold. If the light lights correctly move on to the next item.
Check the solenoid operation by removing the plug and see if fuel flows out when you turn the key to the crank position(again cold engine)
Unbolt the cold start and pull it away from the manifold and see if fuel actually sprays from the nozzle when the key is turned to the crank position again with the engine cold.
You need to leave at least a half hour of so between the "Cold Engine" tests as the switch that controls the cold start injector(Thermo time switch) is electrically heated so if you do the tests back to back you may get false readings.
The fun thing about cold start issues is the measurements take minutes but letting the engine/thermo time switch to cool down can take hours.
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Your question confuses me. Both the injection pump and the CSV are fed by the pressure output from the electric fuel pump (which in this thread seems to be called the high pressure fuel pump - odd). The electric fuel pump is next to the gas tank under the car on the driver side. It IS higher pressure than most electric fuel pumps, but that isn't terribly relevant to your question. There is no mechanical fuel pump, unless you are using that term to refer to the injection pump itself, which probably is best not called a mechanical fuel pump.
Whenever the ignition is on, the electric fuel pump is on and it is pumping gas to the injection pump and CSV (which is normally closed) and then there is a return fuel line that goes back to the tank. So if you just turn the ignition to on, the fuel will just circulate.
The CSV opens for a few seconds when you start the car and it is cold. The diagrams and other posts that you reference probably discuss that enough.
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Your question confuses me. Both the injection pump and the CSV are fed by the pressure output from the electric fuel pump (which in this thread seems to be called the high pressure fuel pump - odd). The electric fuel pump is next to the gas tank under the car on the driver side. It IS higher pressure than most electric fuel pumps, but that isn't terribly relevant to your question. There is no mechanical fuel pump, unless you are using that term to refer to the injection pump itself, which probably is best not called a mechanical fuel pump.
Whenever the ignition is on, the electric fuel pump is on and it is pumping gas to the injection pump and CSV (which is normally closed) and then there is a return fuel line that goes back to the tank. So if you just turn the ignition to on, the fuel will just circulate.
The CSV opens for a few seconds when you start the car and it is cold. The diagrams and other posts that you reference probably discuss that enough.
I missed that the line going to the CSV actually ran from the T that feeds the high pressure/mechanical/injection pump. I understand how the CSV works at this juncture, how it is supposed to work and why it should work. It works great now thank to the help of people here.
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James,
What was the root cause and solution to your CSV cold start issue?
Thanks,
Mark
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There hasn't been one yet; if I unhook the CSV when the car is hot and give it 1/3 throttle it starts every time. The CSV is actuating no matter the engine temp and flooding it; I suspect there's an electrical issue somewhere.
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James, If everything is wired correctly then most likely the thermal time switch is internally shorted. This would explain the CSV being energized with a hot engine.