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Discussion Starter · #1 ·
I own an 86 CJ-7. My Brother has a 84 CJ-7. He told me about a high altitude ground that should be grounded if you run your jeep above 5,000 ft. I live in Colorado an was wondering if any one else has heard of this and if they could tell me where I could find it, my Brother does not know. Just thought someone else might. Thanks

NeverSummer
86 CJ-7

 
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Discussion Starter · #2 ·
I have a 86 AMC EAgle that has the same wire,on mine it is hanging near firewall on oil filter side of engine,its black and has a eye
on it,connected to nothing..I never tried using it since i am below that altitude,and cant now that i did a computer bypass anyway

 
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Discussion Starter · #3 ·
Maybe living at a high altitude has starved my brain for oxygen, but I can't for the life of me figure out why your ground should be any different at any altitude. /wwwthreads_images/icons/shocked.gif

Brad (from the 4 Wheeling center of the universe, 4 corners USA)
 

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/wwwthreads_images/icons/tongue.gif Now, Brad....you KNOW what the actual reason for the wire is, don't you? At a higher altitude, you get crocked easier, and the ground wire makes the headlights work better so you can find your way home./wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/laugh.gif/wwwthreads_images/icons/crazy.gif

CJDave
 
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Discussion Starter · #5 ·
Brad,
You are supposed to wait until 'after' new years before you start responding you posts.....we have all heard how you like to party....

FYI....Grounding a wire is a very common way to send signals to a computer...ungrounded...the signal to the computer is high because of a pull up resistor on the input...so the computer does one thing...ground the input (or wire) and the signal is low...computer does something else. Whats safe about it is that you can tie it to 12 volts or ground and it won't hurt the ole puter...confuse it maybe.....but not hurt....

John......southern CA
84CJ7, 3"lift, 32"BFG, 4.10's, ARB Locker, Solid Axle's, Durabak
 
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Discussion Starter · #6 ·
Sounds like the brother is having some 'high altitude' fun. Would he happen to be an older brother by any chance?
sln
P.S.
Or does this have any thing to do with a heavy duty ground which protects the 'puter from voltage spikes in a lightning strike...this IS more likely to occur at high altitude since you are closer to the clouds and are generally on more dense ground, ie. mountains and rocks, and the voltage potential is therefore much more likely to be vectored in to a higher realm and does the brother also give advice on the potentiometric values of the sincopated rectoverter and what to do about sychronization of the diverter valve on the read high only pin of the central processing unit?
sln


 
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Discussion Starter · #7 ·
It's all perfectly clear to me now, a Jeep with a lightning rod. Great idea, where can I buy one?/wwwthreads_images/icons/laugh.gif

Brad (from the 4 Wheeling center of the universe, 4 corners USA)
 

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You should be able to get one at any farm supply store. Just make sure it is a "High Altitude" model if you are going to hook it to that little black wire./wwwthreads_images/icons/crazy.gif

Mike H.
1983 CJ-7 Laredo
1999 Dakota 4x4
/wwwthreads_images/icons/cool.gifo[[[[o
 
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Discussion Starter · #9 ·
Yes there is a high altitude jumper wire, it should be grounded for operation above 4000 ft. It should be located near your MCU penetration on the firewall and next to the coil. I don't know what it actually does, but it goes to your MCU and has something to do with emission controls. My guess is that it leans out the fuel mixture for high altitude operation. I have heard that some people who live in Denver, who frequently drive from high to low altitudes have this wire connected to a toggle switch on the dash, so they can easily switch back and forth. It is in the wiring diagrams of all the service manuals that I have. Hope this helps. CTjeepnut

 
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Discussion Starter · #10 ·
I connected the H.A. wires on both my CJs when I moved from sea level to 8000ft. The wire is taped inside the wiring harness described in the post above, within a few inches of the coil. The wire has a loop to attach to engine block ground. I know for sure it doesn't change the timing, I did that myself to about 15degrees BTDC. It is likely that it leans out the fuel mixture.

 

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As some of the posts eluded to above there is a wire that was put into the system for high altitude use to create a leaner mixture above 5000 ft. Back in the dinosour days, I was a heavy line mechanic for Jeep in Flagstaff AZ (7000ft) all the Jeeps had this wire connected and we had lots of customers that were snow birds, a common term here put to the people that lived in snow country in the summer and migrated to the desert in AZ during the winter. We had people that would bring thier Jeeps to us each summer, the ones that live in Phoenix and come to the high country to stay out the summers, (Who bought the Jeeps in Phoenix), to get them set up for the altitude. All we would do was hook up this wire in most cases to get the proper mixture, these carbs were referred to as "barometrics" and they were and are a pain in the you know what to work on a get set right. This was around 82 and I'm sure the later models were very similar.
GP'n

 
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Discussion Starter · #12 ·
Gentlemen -
I will be dipped in feathers. I profusely apologize for my tongue in cheek blithering. There really is such a thing, huh? Dave, did you know?
sln

 
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Discussion Starter · #13 ·
this was common with early computer controlled carbs. most did not have any form of barometric control (usually performed by a MAP sensor). so the engineers just added an extra algorithm to the prom that is activated by a ground wire or switch.

as a side note, remember the extremely large vacuum modulators used on th350s? those actually had an altitude compensator built into them.

dan

/wwwthreads_images/icons/smile.giflet it snow/wwwthreads_images/icons/smile.gif
 

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/wwwthreads_images/icons/crazy.gif Hey....stop that gloating!/wwwthreads_images/icons/crazy.gif It's OK to be right, but NO GLOATING!/wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless I've made 'em up myself.
 
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Discussion Starter · #17 ·
Oh come on,im not right very often,cant i least have a moment of glory? sheesh !
course this is all in fun.Isnt it?i think it is,course i could be wrong,naww im right , i think..

 
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Discussion Starter · #18 ·
Does this mean I don't get the Jeep with a lightning rod? /wwwthreads_images/icons/laugh.gif

Brad (from the 4 Wheeling center of the universe, 4 corners USA)
 
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Discussion Starter · #19 ·
I just moved to a portion of Colorado where the elevation is now 8000ft. plus and my 89 Wrangler usually runs like sh*%#! So I just finished installing a newly rebuilt Carter BBD and now it atleast idles but still hesitates a bit. Would this high elevation wire be on a Wrangler as late as 89 or not?

 
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Discussion Starter · #20 ·
Yes there is a wire on an '89 but it's up under the dash near the computer wires [sort of between the radio area and the glove box if I remember correctly]. It has a grey plastic "connector" on it and you need to put a jumper across the two wires in the connector. One wire goes to ground and the other goes to the computer so when you jump the connection w/a wire you are completing the ground to the computer. If you look at a wiring diagram from a factory manual youl see the wire and the exact pin terminal # at the computer harness. You will also need to advance your timing about 7 degrees.
 
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