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Unread 06-07-2013, 10:49 AM   #1
SHUVLHEAD
Registered User
1987 YJ Wrangler 
 
Join Date: Mar 2013
Location: PALM CITY, FL
Posts: 5
1987 YJ crank but no start

Driving down the road, jeep just shut off. Will crank with a weak spark. Not enough to start. Replaced the Coil, still weak spark.
Recently Nuttered, new Cap, Roter, wires and plugs.
Was running perfect since i nuttered it, maybe loading up alittle. Which i think it needs smaller jets in the refurb MC2100 carb i put on it.
Other than that, running great. Checked for loose wires/grounds and nothing.
Any help would be greatly appreciated.

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Unread 06-07-2013, 11:07 AM   #2
Prspallone
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1982 CJ7 
 
Join Date: Oct 2011
Location: elgin, Illinois
Posts: 200
This could be many things. It's always a good idea to start by checking the batteries charge though. Could be something wrong with the fuel pump or lines, it's very possibly something with the carburetor though. While you wait for more people to respond take a quick search of old threads with similar issues, you probably will find your answer. Sorry I can't be of more help, but good luck, wacky stuff happens to my jeep all the time. Sometimes the problem takes care of it's self though!
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Unread 06-07-2013, 11:41 AM   #3
Old4X
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1990 CJ7 
 
Join Date: Nov 2008
Location: Ga
Posts: 4,963
Time for diagnostics.

Check compression

Check timing, timing mark vs. physical TDC on #1 piston.

Check for erratic timing esp abofe 1500 rpms.

Check vacuum reading, should be 21" MSL, adjust for your height above MSL.

Check vacuum needle at idle, should be steady or all but steady.

Pull spark plugs and "read " them for what is going on in combustion chamber.

Check timing chain for slack. Over 7 degrees, replace chain and both gears.

Check fuel pressure at carb with engine running.

Check for restricted exhaust

Did you add a dedicated ground to the black wire (3 wire harness) from the distributor?


Let us know what you find
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418 miles on 19 gallons of gas. Can't beat the BBD !
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Unread 06-07-2013, 11:45 AM   #4
Old4X
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1990 CJ7 
 
Join Date: Nov 2008
Location: Ga
Posts: 4,963
As you are nuttered, you can wire in a GM ICM in about 5 minutes to check if you have a bad ICM. Just the 2 nutter wires, a hot, a ground, and a wire to the neg post of the coil
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418 miles on 19 gallons of gas. Can't beat the BBD !
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Unread 06-27-2013, 10:39 AM   #5
SHUVLHEAD
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1987 YJ Wrangler 
 
Join Date: Mar 2013
Location: PALM CITY, FL
Posts: 5
Got tired of banging my head and took it MEAN MAX. New HEI ignition and the thing runs like a scalded ape.
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