Random hard start and dying 94 4.0 - JeepForum.com
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post #1 of 4 Old 04-05-2006, 02:21 PM Thread Starter
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Location: Dallas,TX
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Random hard start and dying 94 4.0

I just picked up this 94 GC with a 4.0 in it. Every now and then it will crank and crank and not start. Then when I am driving down the road, it will act like it is shifting really hard like it missed a gear, but the tach sweeps towatrds 0 for just a split second.
I replaced the coil the first time it did it with one from Napa. After I replaced it, it strated right up, but I think it was coincidence.
I also have a problem with fuel leaking at the rear of the truck when the tank is topped off. Could these two be related? The PO said he replaced the fuel pump right before I bought it.

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post #2 of 4 Old 04-10-2006, 10:39 AM Thread Starter
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no love for my problem?
weaksauce is offline  
post #3 of 4 Old 04-10-2006, 05:52 PM
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did you change the spark plugs and wires? that could play a big factor in the start up.

how many miles does it have??

also if it is shifting irratically then check the tranny fluid level, if that is fine then check the linkage to the transmission to and from the computer and also any other mechanically linkage

1995 ZJ 4X4
command-trac (NP231) with SYE
K&N FIPK intake
RE 6.5in lift with 33X12.5 BFG MT and no Rear Sway bar
4.56 gears--axle swap soon
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post #4 of 4 Old 04-10-2006, 06:01 PM
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I vote for a bad Crank Position Sensor (CPS). This sensor located on the upper driver side of the transmission bell housing tells the engine when to fire the spark plugs. They have a tendancy to go bad and when they do you either get hard starts, no starts, or the engine dying.


Traded 8/9/07

Black 94 ZJ Laredo 4.0L 42RE/NP231 Command Trac
Sylvania Silverstars, Alpine CD Head Unit, Pioneer 3-Ways in the Doors, Blacked Out Grill, Kolak Exhaust, Clear Corners, Bilstein Shocks, Gas Tank Skid, Rear Hitch, Hitch Wiring, TC Skid, Hellwig RSB, Military FSB, Brembo Front Rotors, OME SS, B&M Supercooler, RE Tie Rod, Limited Power Leather Seats, 30x9.5 Toyo Open Country ATs, Optima Red Top

Next Mods: Upgrade Battery Cables, Sliders, Black Steelies, 3" Lift, Rear Locker, Bumper, HO Alternator, Winch, Driving Lights
dpierson is offline  

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