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Swapped long block, now won't start 92xj

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Old 03-13-2012, 01:33 PM
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Default Swapped long block, now won't start 92xj

Yes, I changed the Crank sensor (3 times). Yes, the wires are in the right order. Yes, the cap is in the right direction. Yes compression is good. Yes the grounds are tripple checked. Yes spark appears strong. Yes replace coil.

Drove the jeep to the lift, swapped long blocks & it just won't fire. Turns like a champ. We've changed out everything including the ECU & nothing changes.

Is there anyone in the Modesto CA Area that could help? Been wrestling with it for a month. Changed everything. I am just at a loss. I just don't know what to do.

I've searched & found threads on multiple forums, but I think I've tried everything.

Last edited by srt4geezer; 03-13-2012 at 01:36 PM.
Old 03-13-2012, 02:08 PM
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When you swapped long blocks did you change the distributor? Was the swapped in engine new or used? Is the cam sensor aligned properly?

If you got fuel, spark, and air, timing is really the only issue you could have. Since you changed out the crank sensor, the cam sensor, timing, and ECM are really the only things left.
Old 03-13-2012, 02:13 PM
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what year motor was put in,fly wheel fom xj installed on new motor used all electrics from old motor?

Last edited by freegdr; 03-13-2012 at 02:15 PM.
Old 03-13-2012, 03:03 PM
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I'll have to check the year on the rebuilt motor we put in. Everything came off the old motor & onto the new motor. Flywheel, Distributor.
Old 03-13-2012, 03:12 PM
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You checked a lot of things having to do with spark from what I read. Did you happen to check fuel pressure? or check to see if your distrubutor is plugged right? Your timing could be off causing it to fire, but not start.(the distributor its self, not the cap)
Old 03-13-2012, 03:13 PM
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Originally Posted by srt4geezer
I'll have to check the year on the rebuilt motor we put in. Everything came off the old motor & onto the new motor. Flywheel, Distributor.
sensors to i assume
Old 03-13-2012, 03:17 PM
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was the rebuilt motor bought from reliable source
Old 03-13-2012, 03:26 PM
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ive replace many engine ,they need fuel,air and spark if you have all three and they dont start timing is off or the new motors no good thats the bottom line..
Old 03-13-2012, 03:59 PM
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I think the compression was 150 on all 6.

Bought it from here: http://www.westcoastengines.com/
Old 03-13-2012, 04:03 PM
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Originally Posted by srt4geezer
I think the compression was 150 on all 6.

Bought it from here: http://www.westcoastengines.com/
you got fuel spraying into cyls not the same as fuel pressure,got spark then its timing
Old 03-13-2012, 04:10 PM
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Ok i'm the guy that did the motor swap. Here is all of the info as I have it. The jeep drove over here and even drivin into the back yard. The swap was done with a motor from hi tech motors and without a hitch, that is until I went to start it.

The problem is the jeep cranks very strong, but will not fire. Things that have been done, new long block, new cap, new rotor, new plugs, new wires, new Dodge crank sensor, new stador (cam sensor), new coil and even a new pcm. I have checked the following, fuel pressure (40 psi), spark is good at the coil but not threw the cap to the plugs (very weak and intermittent), I checked the grounds threw out the engine bay (all good), I have also traced the wires from the sensors to the computer (all are good), also did a compression check (all were the same, 140 I think).

Ive about run out of things to try, need suggestions.

edit, you can smell fuel after cranking and when trying to start with starter fluid it still will not fire. the only glimpse of hope is when the gas is floored.

Last edited by blazinsrt; 03-13-2012 at 04:13 PM.
Old 03-13-2012, 04:25 PM
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did ya pull a plug see if its wet from fuel
Old 03-13-2012, 04:30 PM
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hello...
Old 03-13-2012, 04:31 PM
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Yes all plugs are wet with fuel. I just swapped all relays and still nothing. Funn thing..... I pulled the fuel pump relay and it really try's to start.
Old 03-13-2012, 04:34 PM
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Originally Posted by blazinsrt
Yes all plugs are wet with fuel. I just swapped all relays and still nothing. Funn thing..... I pulled the fuel pump relay and it really try's to start.
stop cranking it your most likely just flooding it pull all the plugs out let them dry off ,when you did the firing order what did you use as reference


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