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post #1 of (permalink) Old 03-07-2001, 10:10 PM
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Vac Switch

I am no longer using the stepper motor on the back of the carb. My question is... do I still need the 2 vac switches on the fire wall that monitor engine vac for the computer? My understanding is that they act like a full trottle switch, but the carb already has one. Also, with the stepper out of the picture, isn't the computer basicly out of the picture making the switches useless?
I need to use one of them for my 4x4 light because that one died and just want to make sure I don't need them.Thanx

'88 Sahara, 4.2, auto.
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post #2 of (permalink) Old 03-07-2001, 10:59 PM
 
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Re: Vac Switch

I'm a little confused as to why you need a vacuum source for the YJ's 4x4 light. The vacuum for the light switch needs to come from the vacuum disconnect circuit, the shift motor on the axle itself. If you look at the shift motor from behind the axle, the port that faces the passenger tire is the 2wd port, the one on the can part of the motor is the 4wd. The remaining port on the left is where the line to the vac switch goes. When the collar slides into the 4wd position, the action opens the pathway from the 4wd port to the switch port. [img]/wwwthreads_images/icons/smile.gif[/img]

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post #3 of (permalink) Old 03-08-2001, 03:05 AM
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Re: Vac Switch

That 3rd vac line from the axle ggoes to a vacuum actuated switch mounted on the fire wall just to the right of the battery on some YJ's. The switch on the fire wall is toasted so my light doesn't work. I wanted to remove all the vac lines I don't need anyhow and just realized today that the 4x4 light switch was the same as the two that tell the computer what's going on. With the stepper unhooked anyway, is there any reason to leave these switches connected?

'88 Sahara, 4.2, auto.
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post #4 of (permalink) Old 03-08-2001, 08:55 AM
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Re: Vac Switch

If you did the "Nutter bypass" you could eliminate them. The computer still has a small, 4 or 6 degree, timing retard based on the 3 and 10 inch switches. This is why the data tag tells you to disconnect them when you set base timing. If you are not sure, just unplug them and go an a test drive and see if you get pinging.

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post #5 of (permalink) Old 03-08-2001, 12:12 PM
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Re: Vac Switch

Thanx Dorfs, I'll give her a try.


'88 Sahara, 4.2, auto.
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