No Spark ---> Ignition Problems--> I'm Stumped??

[Patrick]

Just finished a cam, manifold,coil and carb swap on my newly acquired 87 GW. Problem is that I am not geting any spark to the plugs at all. The coil + terminal shows 12v with ignition on. One of my books indicates that this should be about 6v plus/minus .5v (because there is a resistance wire in the circuit). Have checked all wires from control module to coil/and or dist and all are in good condition with no opens or shorts. Coil is new MSD off road. Connection wire from coil to cap is fine/new. Cap and Rotor are new. This GW had some quirks before this latest change out of parts and I'm wondering if the ignition module is not working correctly. Does anyone know how to test these modules??
I'm stumped because the wiring is a pretty simple affair and yet I get not spark whatsoever. If you have any other troubleshooting suggestions please voice them.

[Dive 30]

Did you get a new timing set with the cam swap? Are you checking for spark at the #1 plug wire?

If so, check for spark at the coil. If you have spark at the coil, you are off time. You need to go back and re-set the engine to #1 TDC on Compression (Stick your thumb over the spark plug hole while you or your helper manually turns the motor in the direction of rotation) you will feel pressure on your thumb as it compresses. Make sure you go through the cycle so that you are positive you are on compression stroke. You can tell you are at exactly TDC by lining up the timing mark on the Harmonic Balancer and the TDC mark on the timing cover. Then you will have to play with your distributor to get it back onto the gear and the oil pump drive. Usually takes me a little bit to get it right. Then you will be timed to 0 degrees BTDC, the motor will run, just not well. Then you can time it to factory specs. Oh, make sure you put some oil or pre-lube on the distributor gear so that you don't have excessive initial wear on your new Distributor Drive Gear.

Just another thought. Hope that helps.

Phil

[ October 21, 2001: Message edited by: Dive 30 ]

[Lindel]

Put a voltmeter on the neg side of the coil, or a 12v lamp. You should see the meter or lamp fluctuate (on and off, or go between 0 and 12 volts). If it doesn't change out the pick up coil in the distributor.

If you've got the stock ignition, then you should have 5-6v at the pos side of the coil, all bets are off if you've installed an aftermarket ignition box.

[Patrick]

Yes, I got a new timing set when I changed out cam. I also painstakenly made sure that the timing position was correct in the very manner you described. How do you check if you've got spark at the coil?? I've read my service manual and this is what it said to do: 1. With ignition(i've got a stock ign) on measure voltage at + terminal---if 6 plus/minus .5 then voltage is correct---if you get bat voltage then remove "I" terminal connection from voltage regulator and see if voltage drops to 6v. If it doesent drop to 6v then jumper from coil - to ground and you should get 6v.
With the ignition on I get 12.28 v at + coil. When I remove the "I" conection from volt Reg. I get 12.28v at + coil. When I jumper from coil - to grd I get 3.38 v. So although the voltage droped as prescribed by manual it dit not go to 6v. The service manual indicates that these conditions are indicative of a faulty ignition control box however the GW ran prior to me swapping carb,maniflod,coil,cam,timing chain???

[Crazy_Jeepman]

I think it sounds like the module. I would get another plug it in if it works great if not you have a spare, and are back to square 1. I have had a perfectly running FSJ, park it in the driveway, go to start it and it will not start, change the module and away it goes. I have yet to have a module quit on me while I am driveing it seems mine always blow when the thing is not running. Good Luck. ;)

[ October 21, 2001: Message edited by: Crazy_Jeepman ]