Fuel pump prime without prime pulse.

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Six_Shooter
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Fuel pump prime without prime pulse.

Post by Six_Shooter »

Is there an easy way, in software to eliminate the injector pulse prime at key on, but still have the fuel pump prime?

I know I could use a programmable output that also triggers the fuel pump relay, and just shut the priming pulses off, but that feels like a hack-around. I looked around the settings for fuel pump and prime pules but there seems to be no way to unlink them, in settings. I'm hoping I missed something here.

For myself this is mostly going to apply to MS3 and MS2 and MS3Pro.

For those wondering why I'd want to do this, there are times when the key could be turned on and off repeatedly in a short period of time for reasons other than the EFI setup/testing and with multiple priming pulses the engine could get flooded. It may not always be possible to go into the ECU and disable the the priming pulses, or that the person working on the vehicle even know about this and disable the fuel pump in some other way. I'd rather have the fuel pump pressurize the system without a priming pulse anyway.
Tha Toy: 1973 Datsun 240Z Turbocharged, and loads of fun, now MS'd
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DaveEFI
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Re: Fuel pump prime without prime pulse.

Post by DaveEFI »

Reduce the priming pulse to near zero? Think making it zero disables the pump prime too.
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billr
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Re: Fuel pump prime without prime pulse.

Post by billr »

I, too, think the shortest pulse the FW will take should do it for you. But does it really matter? If you have an FP sensor, check to see how fast does the FP comes up once cranking is detected. For me it is 700 msec, and that is just a few extra cranking revolutions. I kind of like it to do that, to get oil pressure up a bit before it fires.
turbo conversion
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Re: Fuel pump prime without prime pulse.

Post by turbo conversion »

Set the priming pulse to 0.1 and you can cycle the switch several times and not flood the engine.

David
1976 Datsun 280Z L28ET Garrett GT35R T3-T04E stage3 50 trim 63 A/R housing custom grind cam 2000-6000 rpm 440cc injectors intercooled 18 lbs. boost
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