Author Topic: Jeep dies  (Read 2028 times)

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Offline jfrabat

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Jeep dies
« on: August 20, 2009, 09:21:22 AM »
OK, so after I put the new timing chain and camshaft in, the Jeep runs fine.  But if I run on the highway for some time, and then run it a low RPM's (or idle), it dies on me (no sputtering or anything, it just dies).  If I try to restart it either by popping the clutch or using the starter (without turning it off) it does not start, but if I switch the ignition off and then started, it comes right back to life.  Any ideas as to why this may be happening?  By the way, the serpentine belt is a bit loose, so I am thinking maybe the alternator is sliping (I have to adjust it tonight, as the Jeep is shipping tomorrow!), but could that be the cause?
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline sharpxmen

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Re: Jeep dies
« Reply #1 on: August 20, 2009, 10:10:04 AM »
OK, so after I put the new timing chain and camshaft in, the Jeep runs fine.  But if I run on the highway for some time, and then run it a low RPM's (or idle), it dies on me (no sputtering or anything, it just dies).  If I try to restart it either by popping the clutch or using the starter (without turning it off) it does not start, but if I switch the ignition off and then started, it comes right back to life.  Any ideas as to why this may be happening?  By the way, the serpentine belt is a bit loose, so I am thinking maybe the alternator is sliping (I have to adjust it tonight, as the Jeep is shipping tomorrow!), but could that be the cause?
it won't die b/c the alternator is slipping.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline jfrabat

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Re: Jeep dies
« Reply #2 on: August 20, 2009, 11:55:40 AM »
Well, it just died on me 3 more times today; honestly speaking, it feels like the ignition is failing, because it does not sputter or anything.  I have another coil at home; I'll try replacing the coil (and plugs, to reduce the gap back to .035) and see how that goes.  I'll probably change the ECU just for good measure (I have another at home as well).  Let's see if that cures it, but if it IS the coil, I have to find out what the heck is going on, as I aready had a coil die on me about 3 or 4 months ago, so something is causing the coils to burn up (again, if it IS the coil).
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline sharpxmen

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Re: Jeep dies
« Reply #3 on: August 20, 2009, 11:59:47 AM »
do you have an aftermarket ignition? just wondering since you said you want to reduce the gap back to .35 - what are you running now?
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline neale_rs

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Re: Jeep dies
« Reply #4 on: August 20, 2009, 12:20:36 PM »
Sounds like the crankshaft position sensor is going bad.
'95 YJ, 33 x 12.5 mud tires, RE 4.5 ED lift, Atlas 4 speed, rear D44, ARBs front and rear, 4.56 gears, 8000# winch

Offline Jeffy

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Re: Jeep dies
« Reply #5 on: August 20, 2009, 12:28:16 PM »
I doubt it's the spark plugs.  If it's unable to jump the gap, you will get misfires.  My guess is it's the Camshaft Position Sensor since the cam was replaced.  An unplugged or bad CPS will cause intermittent stalling and dying.
« Last Edit: August 20, 2009, 12:31:31 PM by Jeffy »
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Offline jfrabat

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Re: Jeep dies
« Reply #6 on: August 20, 2009, 12:36:01 PM »
Sounds like the crankshaft position sensor is going bad.

I replaced it about a year ago or so...  Could it be bad AGAIN?
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline neale_rs

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Re: Jeep dies
« Reply #7 on: August 20, 2009, 12:46:00 PM »
It could be the CPS connectors or wiring too ...
'95 YJ, 33 x 12.5 mud tires, RE 4.5 ED lift, Atlas 4 speed, rear D44, ARBs front and rear, 4.56 gears, 8000# winch

Offline jfrabat

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Re: Jeep dies
« Reply #8 on: August 20, 2009, 12:47:20 PM »
Well, I only have tonight to get it fixed, so I think I'll replace it as well...
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline neale_rs

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Re: Jeep dies
« Reply #9 on: August 20, 2009, 01:01:02 PM »
Good luck.  Working under pressure like that is not much fun.

'95 YJ, 33 x 12.5 mud tires, RE 4.5 ED lift, Atlas 4 speed, rear D44, ARBs front and rear, 4.56 gears, 8000# winch

Offline jfrabat

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Re: Jeep dies
« Reply #10 on: August 20, 2009, 09:27:25 PM »
Good luck.  Working under pressure like that is not much fun.



Yeah, it was not fun, but looks like it was either the CPS or the ECU.  I am leaning more towards the ECU.

I replaced mine ('94) with one I got a while back ('95), and I noticed 2 differences between them: (1) the '95 uses screws to keep it shut, while the '94 uses plastic tabs, and (2) the '95 had a HUGE heatsink inside the computer which the '94 lacked.  Upon looking closer inside the old ECU, I noticed that the computer does have the tabs to install the heat sink, so I am thinking someone played with this ECU before I bought the Jeep.

Anyway, with the new ECU, the first change was immidiate; idle was about 200 RPM's lower than before.  I also took the Jeep for a spin (about 40 miles)and there were no problems.  I guess tomorrow will be the definitive test.  I doid not change the coil (which would mean changing plugs again to reduce the gap), but if it fails again, I will change this (got a coil and 4 plugs sitting in the garage).

Felipe
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline jfrabat

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Re: Jeep dies
« Reply #11 on: August 21, 2009, 06:49:20 AM »
Drove to the office today; still no issues.  Fingers still crossed!
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline neale_rs

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Re: Jeep dies
« Reply #12 on: August 21, 2009, 08:10:10 AM »
Glad to know it's working again.  Here in Mexico a lot of auto electric shops fix ECUs.  They say it is usually just some capacitors that need to be replaced.  I have no idea how long these repairs last but it could be something like that was done to yours.
'95 YJ, 33 x 12.5 mud tires, RE 4.5 ED lift, Atlas 4 speed, rear D44, ARBs front and rear, 4.56 gears, 8000# winch

Offline jfrabat

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Re: Jeep dies
« Reply #13 on: August 21, 2009, 05:48:17 PM »
Glad to know it's working again.

Well, I spoke too soon.  The Jeep died today, and it's not ignition; it's fuel.  There is no fuel at all at the rail, so I'm having it checked.  What sucked the most was that it was running fine all day, but on the way to the port, DEAD!  I missed the boat, and now I have to ship it next week (which will be a VERY busy week for me!)
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline chardrc

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Re: Jeep dies
« Reply #14 on: August 21, 2009, 06:26:33 PM »
the jeep just doesn't want to leave home :'(... hope you can get it figured out.. it sucks being under pressure and have stuff fail.
1990 YJ 4cly, ax5, 2.5 inch BDS lift, 31 MTr\'s,  Powertrax-lockers all around, track-bars removed, boomerang shackles, warn m8000 winch, electric fan. [sold but not forgotten]

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