Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

Have you taken the cap off the disrtibutor and watched the rotor spin around as someone cranked the motor? Maybe your distrib gear is slipping, or your timing chain? A coil works VERY simple, BUT requires something to short out it's leads to discharge (i.e. the rotor lining up with a cyl contact on the cap) let me know what you find!

/wwwthreads_images/icons/cool.gif Big Ed
'88 YJ, 4" susp,3" body,33's,283 Chevy V8,TH350,4.11's,D30,D35c

 

Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

This is a neighbor of mine with this problem on here and we did check to see if the rotor button was turning inside the cap and it turning as well as my jeep. There's just no spark/fire leaving the new coil but power getting in it. I'm clueless with it?

 

Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

Do I understand this correctly?

There is spark from the coil, but it stops at: (The problem is you don't know)...
The rotor is turning, but the engine: is or is not: turning over?

If the engine turns over, is it just not catching? Did any part of the engine get wet? My money is still with a cracked distibutor (the part that enters the block, not the cap)... Though... if it's coming from the coil... ???? I'd take it in, distributors can cost about $300.00 from a parts store... Is it still under
warranty?

Jon - YJ94
http://www.obsessiveoffroad.com

 

Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

Take a voltmeter and measure the voltage on the pos and neg terminals of the coil. While cranking, you should have about 12VDC on the pos terminal. On the negative you should have no more than about 6 volts....if I remember correctly, it should be about 4. Without getting too technical, the neg terminal is connected to a solidstate switch (transistor) in the ignition module. (I am assuming that you have fuel injection). With a fast voltmeter you should see the neg terminal pulsing...this is the fire signal for the coil. If you can't see it with the DVM, try an o-scope...and if you don't have an o-scope, use the old style DVM with an actual meter...you should see the needle pulse. If you don't get any pulsing..then the problem is before the coil.

If thats the case...spend the bucks and buy a good manual and then take it one step at a time. It helps if you can find another jeep (same year) to compare against. Be cognizant of the fact that many parts of your engine are close loop systems, i.e., one part can fail but it makes other parts look like they are dead too.

Let us know what you find...

John......southern CA
84CJ7, 3"lift, 32"BFG, 4.10's, ARB Locker, Solid Axle's, Durabak

 

Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

Yeah the engine turns over but there's no spark from the coil. I'm well out of warranty now so that's not an option. The engine never got wet either.

 

Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

Ya the moter turns over. I know the postive side of the two wires going to it has power but I haven't got a volt meter yet to to check the negitive side. I did take the distibuter off and the shaft is turning. My dad told me that I could have broke the timing chain or belt which one it has on it but I don't know how to check it. I was in the snow and I was kicking the snow up alot but it couldn't have gotten to wet could it. Alright thanx everyone for all your help and please post if you have anymore helpful hints.

 

Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

If you're really fed up with it you could always take a match and a gallon of gas and call the insurance company.

 

Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

If the dist is rotating then its not a broke timming chain. The dist is driven off the cam which in turn is turned by the timming chain.

Taking into account how it failed, my first guess is the ign. module or some related device. Without a voltmeter, its almost impossible to troubleshoot unless you want to try the shotgun approach....i.e., keep replacing parts until it works.

John......southern CA
84CJ7, 3"lift, 32"BFG, 4.10's, ARB Locker, Solid Axle's, Durabak

 

Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

Did I miss something....I don't know about all this computer junk in these new vehicles but the primitive way to do it is pull out a spark plug ,stick it in the wire ,ground it ,and have someone crank the engine ,see if there is any spark jumping the gap, don't hold it with your hands use insulated pliers.if there is spark it has to be fuel system,if no spark it must be between the plug wire and the coil where you have power.maybe you burned something out inside the distributer itself magnetic Pick up or something.

Learn to let go of what does not serve you ,but forces you to serve it

 

Re: Got fire to coil but still wont start for a 94 YJ(please read and help)

I think the easier way to test for spark at your plugs is to just hook up an inductive timing light to a wire, and crank the engine and see if it flashes. If it does, you've at least got some fire going to the plugs... Unfortuneately this method won't tell you how hot the spark is...

Tim
/wwwthreads_images/icons/cool.gif '79 Suburban 4x4 454, 35x12.5s
/wwwthreads_images/icons/wink.gif '85 S15 4x4 2.8l, 235/75's