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Unread 02-17-2015, 12:55 PM   #1
jb19d
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90 yj 4.2 wont start!! Help!! Please

My 1990 Jeep Wrangler YJ 4.2 won't start, turns over but sounds weak. So far I have replaced carburetor, (weber), spark plugs, distributor cap and rotor, fuel filter, starter, starter relay and ignition control module, when I put the new starter on it would try to start for a second then nothing!!! Please help before I replace every part in this engine!

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Unread 02-17-2015, 01:51 PM   #2
Que89YJ
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Welcome to the forum. If you get a chance please fill out the profile to help figure out what you are dealing with. You said its turning over but sounds weak? Like it is struggling to spin the engine?
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Unread 02-17-2015, 02:29 PM   #3
Jeepsr4me
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Battery is not in your list of replaced thingss
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Unread 02-17-2015, 02:47 PM   #4
dancytron
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Bad battery cables or bad connections. Especially the main ground cable.
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Unread 02-17-2015, 02:52 PM   #5
jb19d
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Yes it is struggling to turn over. I have put a full charge on the battery before I guess I could swap out the cables?
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Unread 02-17-2015, 03:15 PM   #6
jbolty
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Why would you change any parts until you know what's wrong with it?

I would begin by testing the battery. Does it spin normally if you jump it from another vehicle? What about pushing or towing to start it; is it a standard transmission?
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Unread 02-17-2015, 03:18 PM   #7
Jeepsr4me
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Cables can corrode on the inside and the clamps or terminals can get a coating that shields it from making good contact.

I take a knife and cut the inside of the battery terminal and the lug on top of battery till it is nice and shiny
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Unread 02-17-2015, 04:11 PM   #8
mickcollinsb16b
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i agree with all previous posts to check out your battery cables before sending anymore cash on other parts. cheap and easy to do that is where i would start.
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Unread 02-17-2015, 05:12 PM   #9
jb19d
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The battery cables are installed. Same issue? Battery is good o had it checked and charged it for 24 hours. Anyone else got any ideas? Compression maybe?
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Unread 02-17-2015, 06:18 PM   #10
Jeepsr4me
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Try jumping the relay at the solenoid...
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Unread 02-17-2015, 08:11 PM   #11
Que89YJ
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It is battery cables or starter.
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Unread 02-17-2015, 08:15 PM   #12
Que89YJ
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You can use jumper cables to bridge the wires from the battery to the starter to eliminate the wires. Do both positive and negative. If that doesn't change it then jumper to another battery of a car and see if it's any better. If both of those are good then you need a starter.
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Unread 02-17-2015, 09:07 PM   #13
YJ8
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When I trouble shoot I make it easy-- You need three things for the motor to run-- Fuel, Spark and Compression. Figure out which one you are missing and you are 90% finished with diagnosis.

If it does not turn over the post above have you covered.

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Unread 02-18-2015, 12:15 AM   #14
bergovoy
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like the above poster said you need to diagnose things before throwing parts and money at it and praying that it will fix whatever problem exists.

to start the diagnosis, I usually try some quik start fluid or brake cleaner/parts cleaner, and give a short squirt into the carburator or air intake assembly, then try starting the motor..

if the motor tries to start, but doesnt stay running, then your problem is a fuel related problem... if it doesnt try to start then it probably is an electrical problem...

so, go ahead, give it a shot and report back
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Unread 02-18-2015, 06:49 AM   #15
jb19d
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I have already done the starting fluid, and it still sounds exactly the same. What about timing?
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