Fuel Injector Questions
09-29-2004, 12:05 PM
#1
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Fuel Injector Questions
1. Is it possible for a fuel injectors performance to degrade as it heats up (if it even heats up) or rather the longer the car is running the worse it's performance gets??
2. If a fuel injector isn't putting out a good spray pattern, more like a stream, this would obviously cause less than perfect atomization. BUT, would it cause the mixture to not burn all the fuel showing a rich condition on a data logger??
3. Could a high RPM leaning out condition cause damage to injectors. The A/F ratio didn't go past 14.0 from 13.0.
2. If a fuel injector isn't putting out a good spray pattern, more like a stream, this would obviously cause less than perfect atomization. BUT, would it cause the mixture to not burn all the fuel showing a rich condition on a data logger??
3. Could a high RPM leaning out condition cause damage to injectors. The A/F ratio didn't go past 14.0 from 13.0.
09-29-2004, 01:25 PM
#2
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Re: Fuel Injector Questions
1. The injectors are basically "solenoids".... current passes through a wire coil and the magnet pulls the injector open. Heat could affect the injector electrically, if the insulation is breaking down at high temps, or mechanically if the plunger is getting crudded up with deposits. Yes, they heat up, and heat can affect them.
2. Your "batch fire" 93 is going to be less sensitive to injector spray pattern than the 94 and newer "sequential" injector setups. Your injectors fire once each crank revolution, whether the valve is open or not. As a result, there usually isn't any air being pulled in the runner, and the fuel just sprays against the back of a HOT, closed intake valve, and evaporates. Probably evaporate faster and more uniformly if its in small, atomized droplets, but it wouldn't be affected as much as a sequential injection setup, where there is air flow moving into the open intake valve along with the atomized fuel. Of course when the duty cycle gets high, even the sequential injector is going to be firing against a closed valve.
3. I don't see how the A/F ratio could hurt the injector. The biggest problem with an injector is the heat that pours up out of any open intake valves when you shut the engine off. That will carbonize the fuel on the tip of the injector.
2. Your "batch fire" 93 is going to be less sensitive to injector spray pattern than the 94 and newer "sequential" injector setups. Your injectors fire once each crank revolution, whether the valve is open or not. As a result, there usually isn't any air being pulled in the runner, and the fuel just sprays against the back of a HOT, closed intake valve, and evaporates. Probably evaporate faster and more uniformly if its in small, atomized droplets, but it wouldn't be affected as much as a sequential injection setup, where there is air flow moving into the open intake valve along with the atomized fuel. Of course when the duty cycle gets high, even the sequential injector is going to be firing against a closed valve.
3. I don't see how the A/F ratio could hurt the injector. The biggest problem with an injector is the heat that pours up out of any open intake valves when you shut the engine off. That will carbonize the fuel on the tip of the injector.
09-29-2004, 01:39 PM
#4
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Re: Fuel Injector Questions
Ok, just wanted to clear that stuff up. Still trying to track down my problem, and since I don't seem to have a leaky injector, I doubt those are my problem.
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