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post #1 of (permalink) Old 08-25-2004, 07:49 PM
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4.2 question

On an 89 4.2, what vacuum hoses and switches be disconnected and removed? The motor is in an 87 wrangler. I will be installing a posilock unit so I know I will be eliminating all of those vacuum lines. My goal is to elliminate all except the dist. and pvc system. Also can I disconect the egr without harming the motor.

Any help would be great THANKS!!!!!!
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post #2 of (permalink) Old 08-29-2004, 04:17 AM
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Re: 4.2 question

If you want to improve the way it runs....then you don't want to remove the vacuum lines...it will only run worse. Contrary to backyard belief, disconnecting all the vacuum lines does not help....in fact, most of the stuff is there to improve driveability......and they do not hurt your performance or gas mileage.....take them all off and it will most likely run worse and spit out more emissions.

For example....the fresh air pulse system. Take off those lines and you will most likely start getting back firing. Leave it on, no back fire and the exhaust is a little cleaner.

No doubt it gets really cold where you live....change things and you can expect your morning warm ups to take a lot longer.....assuming that it starts at all.

Do you like the smell of raw gas? Disconnect the vacuum lines to the charcol canister and you will get plenty of raw gas smell. Leave it hooked up properly and you might get just a slight increase in MPG as you burn off the trapped raw gas. One thing is for sure, it does not take away any power.

About the only item that you can disconnect without serious repercussions is the EGR.....that is if you like the smell of exhaust fumes....
post #3 of (permalink) Old 08-29-2004, 01:47 PM
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Re: 4.2 question

I've been on hiatus from jeeps for a while and I'm just getting back into it, so excuse me if I'm confused but I believe what you want to perform is a nutter bypass. This eliminated the computer and some of the vacuum lines. do a search on the board for nutter bypass and see if it helps.

Again, I might be confused cause it's been a couple years
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post #4 of (permalink) Old 08-29-2004, 09:25 PM
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Re: 4.2 question

Between the Nutter bypass and installing a Webber carburater, I've been able to eliminate everything except the vacuum advance and the PCV. BUT, I live in an area that doed not have smog testing.

Good luck
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post #5 of (permalink) Old 08-30-2004, 01:55 PM
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Re: 4.2 question

The YJ in Nuttered. It did get 5mpg and it was all you could to to keep it running. there was a lot of inconsistancies at idle as well. Now it get 12mpg and runs better than ever. (with exeption of a bad choke). We also do not smog testing.

I installed a new CAT and it does not spurt out foul smelling exhaust. I also do not have raw gas smell. This is hands down the best imporvment I have done to the YJ. Now it just needs something besides that Carter carb in the intake....
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