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Unread 02-08-2012, 10:58 PM   #1
Jared_bc
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ZJ 4.0 rebuild, Won't start, has spark, has fuel.

Alright, searched high and low and this topic never seems to get solved so I'll start my own.

1995 zj, just threw in a new motor. Turned her over and she fired up instantly. Ran it for 5-6 seconds and shut her down. Now she won't fire again.

Cranks over, fuel in the cylinder, and gets a good spark.

NOT the Crank position sensor, as it GETS spark and fuel. Unplugged and re connected PCM, relays, etc. also checked all fuses etc.

TIMING is also brought up often, but TDC on cylider 1 matched perfectly with the distributor.

I'm also using the same original "fly wheel". Going to check all grounds, vaccums and connections again. Going to try to dry the cylinders out and use dry/clean plugs.

Will get a code scanner tomorrow, as well get my fuel pressure checked ( high or low; should still burp or attempt to fire)

This has been hell, no idea what too do so please, questions and advice are welcome!!

I HAVE READ ALL TOPICS ON THE SITE HERE AND NONE OF THE METHODS OR IDEAS HAS PROVEN SUCCESSFUL; any ideas???

-Jared


Last edited by Jared_bc; 02-08-2012 at 11:29 PM..
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Unread 02-09-2012, 12:47 AM   #2
Oldfrog
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Just thinking out loud here...so if anything strikes a chord with you....try it.

You say you're getting fuel and spark. I would assume you're getting air, too.
I have to assume you are getting a hot enough and consistent spark. also.

You also think the timing is Ok.

That leaves one main thing to check:
It's flooding. ( duh...).. I'm wondering if it's getting too much fuel while trying to start ? If so....why? Injectors all stuck open? Doubtful. But depending upon what the TPS is telling the PCM, maybe it's possible. So I'd pull the TPS out and reinsert it...just in case.

I'd also hook a code checker up to it and see if it ran long enough to tell you anything.
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Unread 02-09-2012, 01:27 AM   #3
hdrocknroll
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I don,t think you really need a code checker for a 95
Did you check codes by turning key off and on?
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Unread 02-09-2012, 02:38 AM   #4
Jared_bc
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Hey guys,

Did the old "key in ignition" code read; got code 12 (batt was disconnected from pcm in last 50 starts) and 55 (End of History).

In the morning I will check TPS. As well put in the old plugs (dry and clean), old coil (was working fine but replaced with a newer-used unit).

Actually it has come down to a full on volt meter testing frenzy. There isn't a whole lot of electronics on this thing so I should be able to whip through the Engine control system.

Thanks for the ideas guys! I believe there is a solution, somewhere.
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Unread 02-09-2012, 09:15 AM   #5
pincheburro956
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this may be something simple, but will cause your engine to die after a few seconds.

have you disenaged the anti theft. put the key in the rear hatch and lock/unlock a few times. then try it.

just a thought.

edit: try disconnecting the battery, reconnecting and when/if your headlights start flashing, do ^^...
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Unread 02-09-2012, 03:20 PM   #6
Jared_bc
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Alright after many phone calls and hours staring into my computer screen, a few possibilities have surfaced.

Reset/discharge PCM and other circuits (Haha please correct me if I'm wrong - or the tech was wrong who told me this). Disconnect the (-) batt cable and using a screw driver connect (-) batt cable to the positive terminal for 10+ seconds---- I figured leaving the jeep unplugged for so long would be enough to reset anything. REASONING: The idea behind the is that the PCM is so out of wack from the Old motor and the hard life she had; resetting this would allow her to learn with a "fresh" mind. But is it possible that the PCM is actually "dumber" now?

Went over the vaccums, electricals, etc. All was good.

*Still need to Volt test my sensors, and Have the fuel pressure checked with a gauge. Also will move the Crank Shaft Postion Sensor around - touchy clearences.

The days attempted start: So, dry plugs, dry cylinders, everything checked okay. Putting the pedal to the floor for this start up (since the plugs were soaked in fuel when i took em out, as well the stench of raw fuel from the tail pipe; Maybe to rich/much fuel.) This basically kills the fuel delievery (anti flood??).
Turned the key, everything engaged (fuel pump etc), then pedal to the floor and holding it there I cranked it over. Couple sputters, and a stutter, and.... I let go the pedal, it goes to just cranking over BUT very weakly, as the battery finally decided it wants to be charged.

Yup basically says very little, about the problem or the progress.

And Luckly I don't have the anti theft.
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Unread 02-09-2012, 04:17 PM   #7
pincheburro956
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Try finding the yellow/purple wire in the drives side kick panel, and ground it. Maybe u do have the anti theft, just don't know it. I know my anti theft kicks in after a dead battery, and I have to deactivate it, or it won't start. Much like ur symptoms....
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Unread 02-09-2012, 06:20 PM   #8
Jared_bc
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Little update:

Battery charged so I decided to give it one little shot, Pedal to the floor cranked it for 6-7 seconds to make sure it was "fresh" and not flooded. She sputtered for a second, than just cranked. So I figured I'd feather the gas, Got a few stutters and than gave a little more. Stopped there as it was just a small test.

Fuel pressure was somewhere near 35ish +/- . So overall fuel system is good?.

Going to try to reposition the the distrib. as well rechecking timing, put on (old) but "known" working coil.

No luck finding the anti theft. Again I'm a 1995 Zj Laredo; didn't think I had anti theft other than a kill switch. Oh and a key fab strictly for the doors.
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Unread 02-09-2012, 10:35 PM   #9
Oldfrog
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Why are you even touching the gas pedal while trying to start it? Because it's been flooded and you're giving it air ? It's not a 2 stroke...chuckle... ( although I wish they were !)

As for resetting the PCM, if it's like my 97, just disconnect the negative bat cable and turn the ignition key to the ON position for 3-5 seconds. Then wait a minute or two, reconnect bat cable and hit the starter.

I'd double check that spark too.
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Words of wisdom, Posted by Zeejay:
"..it's not air, it is the opposite of air... suckage so to speak."

Stalling? Work through Zeejay's list
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Unread 02-10-2012, 12:53 AM   #10
ratmonkey
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Why are you mashing the pedal to the floor, theres no choke to set.
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Unread 02-11-2012, 01:45 AM   #11
Jared_bc
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Mashing the pedal and holding it on start up actually kills the fuel flow completely AFTER an intial fuel injection. Thios fuel kill could help air out your fuel soaked plugs/excess fuel. Also may allow for the spark to at least have a chance to ignite instead of being completely soaked. Also we suspected flooding of the cylinders as there IS fuel and Spark but no Pops or sputters = too much fuel, or There is no spark even though we are positive there is one. SO stop the flooding and the spark plugs get a chance. and this worked. got some pops sputters and stutters. ONLY while holding the Pedal down (3-4secs), than feathering it. BUT who know when your this desperate anything can seem like its having an "effect".

And after another day of no luck, i'm replacing some parts as well. Also going to start a complete written list, with a process of elimination. Yea I know, this is the first thing i should have done. And it was, but now it'll be written down.


Thanks again for the Input

Cheers,

-Jared
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Unread 02-11-2012, 02:15 AM   #12
phitmein
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" Fuel pressure was somewhere near 35ish +/- . So overall fuel system is good?. "

---------------------------------------------------------

Uh-umm, maybe way low in my book ???

I am puzzled here, that if that is so, why the old motor ran and the new one won't ?

That is not near enough fuel pressure right ???

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Unread 02-11-2012, 02:35 AM   #13
phitmein
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you greatly moved around many wires in the change over no doubt .

Check all the primary electical connections for wear,tear, solid connections etc.

The batteries connections both in and out,starter,coil etc.

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Unread 02-11-2012, 05:11 AM   #14
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If you have a kill switch, you may have an after market alarm. I've never heard of one coming from the factory with a kill switch. This could be your problem. Check the wiring to the kill switch. See where those wires go. Possibly there's a relay involved that has gone bad. If that's not the problem, check and or replace you spark plug wires. Most wires are made like crap. All you have to do is pull on them a little too hard and they're shot.
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Unread 02-12-2012, 04:47 PM   #15
Jared_bc
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Thanks again everyone!

Got it fired up today but quite rough with minor misfires (may have been cause 1 plug wasn't on fully) (no back fires). Have been playing with the Indexing of the ditributor.

Is anyone familiar with Indexing for each year??? Apparently there is a 1994 and pre indexing; 4 o clock compared to 5 (1995+)???

Have the Dist indexed at 4 instead of 5 now. REFUSED to run at 5.

This all doesnt makle a lot of sense considering the timing was/is good.
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