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Old 07-16-2023, 03:06 PM   #1
littlemanjoe
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Default 2 step & pressure switch

Has anyone ever had an issue with your 2 step not turning off clean during the launch?

I have developed a studder during the launch.

It shows the O2's going rich almost like it's a ignition thing.
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Old 07-16-2023, 06:29 PM   #2
Willyracer
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Default Re: 2 step & pressure switch

I assume you have a data recorder in the car. We bring the
12v signal from the pressure switch / 2 step into a digital input
Then you can see the 12 v drop and rpm increase. Our O2 sensor goes
rich on the hit also.I assumed it has to do with the vacuum secondary
in the carb
David
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Old 07-17-2023, 10:46 AM   #3
SDT1DYI
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Default Re: 2 step & pressure switch

Quote:
Originally Posted by littlemanjoe View Post
Has anyone ever had an issue with your 2 step not turning off clean during the launch?

I have developed a studder during the launch.

It shows the O2's going rich almost like it's a ignition thing.
Yes, a bad Pressure switch can cause this. I would change it out .

Steve Teeter. Stk/SS 620
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Old 07-17-2023, 11:21 AM   #4
littlemanjoe
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Default Re: 2 step & pressure switch

David, I do have a Racepak. I will order the 12 volt event sensor.


Steve, good point. I will change it out while I'm at it.

Thanks,
Mike
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Old 07-17-2023, 03:42 PM   #5
Plyguy63
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Default Re: 2 step & pressure switch

Quote:
Originally Posted by littlemanjoe View Post
David, I do have a Racepak. I will order the 12 volt event sensor.


Steve, good point. I will change it out while I'm at it.

Thanks,
Mike
Some pressure switches have buna type o-rings or wetted parts. Buna rubber is not compatible with brake fluid. EPDM rubber is compatible with brake fluid. Virtually all brake o-rings, seals, etc are edpm rubber. Not sure as to what extent that has with the switch, but I know one person who had a switch go bad and his had buna rubber parts.
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Old 07-19-2023, 06:29 PM   #6
B Parker
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Default Re: 2 step & pressure switch

I get your using brake pressure switch but are you using one in conjunction with a button on the brake pedal. If you are that's the first thing I would get rid of.
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Old 07-24-2023, 10:04 AM   #7
Coleydog
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Default Re: 2 step & pressure switch

What is the switch to buy?
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Old 07-24-2023, 03:28 PM   #8
Plyguy63
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Default Re: 2 step & pressure switch

I was doing research on switches and most have buna rubber. I think there is a place on the east coast that has epdm rubber pressure switches. I think that it is saved on my work computer. I will check and see.
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Old 07-24-2023, 11:22 PM   #9
littlemanjoe
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Default Re: 2 step & pressure switch

If someone could share what brand pressure switch they have had good results with it would be greatly appreciated!
Thanks,
Mike
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Old 07-25-2023, 11:16 AM   #10
weedburner
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Default Re: 2 step & pressure switch

I use a Harley brake lite switch, no problem in the 5 years it's been in place.
I've also used Napa SL147 and SL143, both VW brake lite switches.

Grant
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