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Old 30-09-2009, 02:55 AM
RICE RACING RICE RACING is offline
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Join Date: Oct 2003
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Quote:
Originally Posted by Richard L
You are right, the FJO didn't seem to switch to peak and hold at around ~4 A. I am not sure of the peak can only be triggered above two mS, even the current is allowed to creep pass the 4A threshold.

However, it shouldn't any affect on your idle and light cruise unless the injectors are over heating. If this is the case, it might create local vapuor lock. When you open your throttle, the higher fuel flow may take away the heat from the injector winding.
The funny thing about all this is that it gets better when the engine gets hotter and the intake manifold and fuel rail heats up (all AFR's and timing staying constant). It is perplexing to me as I dont understand why it is doing what it is. This morning I set the injector lag time to 0.750 milliseconds and it is much better (re trimmed the fuel mapping so that was constant) than the 0.550 millisecond value.

Do you think I should eliminate the FJO and go to good old resistors and see who things function? I just cant figure out why the engine wants to stop if I have spark and fuel and the injector opening timings are fully visible on the scope :? I always seem to come up with these odd ball problems.

Here is what FJO had to say about the capture I gave them.

Peter,

The reason the injector current rises in a slope is because it is an inductor. Current through an inductor does not turn on/off instantly, that is the electrical properties of an inductor. This will also vary depending on the inductance and resistance of the injector as well as the supply voltage. The box is connected to the ground side of the injector and controls the current at that end so the voltage is irrelevant. However, you will see some voltage at the ground because there is always some ground resistance. With 4A and 1.4v you have a ground resistance of 0.35 ohms. This includes the ground resistance where the driver is grounded. The current measurement depends on how you are measuring it. The only accurate method is by using a fast response inductive pickup on the ground-side of a single injector. What is the injector pulse width during these random lean spikes?

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