8 plugs at once?

[Stinky]

I'm doing a bunch of stuff w/my 720.  I notice that the exhaust plugs are not firing.  I've read that they are supposed to fire all the time.  But, my manual has a chart/table in it that shows all the conditions that must be met for it to run on 8 plugs (temp below 70, clutch, gear position, below 2,400 rpm and one of the smog controls).

 

Let me go back to square one....My tach starts bouncing.  I get the DW to order a new one off Amazon.  I put it on and it is dead.  I wire it into the existing wires...cutting 6" or so off a duh back (off the back).  Before I send it back, I decide to wire it straight to the motor, under the hood....noting on the exhaust coil and when I put it on the intake coil...VOILA.  Its alive.  Hmmm...maybe there was nothing wrong w/the old tach...but I'd already salvaged teh wires off it and chucked it.

 

I switched the wire to the other coil and all seems fine.

 

Back to the spark...I HAD (now I don't) a very tiny spark on the exhaust.  I switched coils...nada (Spanish for nothing/Not A).  So, I started digging in the manual and found the above....I was fooling w/the oil pump at the time also.  I ran a jumper between the coils and immediately I had spark.

 

When I drove it...I made it about 2 miles and the little bitch died on me.  The wife towed me home w/duh mini-van...OH the disgrace.   It will run, sometime, after you crank the heck out of it.  It POPS...I mean gunshot pops.  On the way home, I pop the clutch and end up blowing out the muffler's seam.  Spark is weak and intermittent.  Remember this...the timing is right on, exactly correct.  

 

I start this big long trouble-shooting deal as I assume that I've fried the ICM.  I go down the list...and pop the cap, the rotor spins like crazy.  I find the retaining bolt laying in the dizzy.  I see that the lock-washer is compressed...almost flat.  So, I get a new bolt, washer and lock washer and Lock-Tite it in place.  It fires right up (which it had already done...2 minutes after I found the bolt).  But, I'd already removed my jumper wire.

 

SOOOOOO, finally, here it is.  If it were your bucket of bolts, which you love driving.  How would you wire it? 

 

I'm thinking of:

Running a wire from the intake coil's + terminal to a switch then to the exhaust coil

OR...just running a wire between the coils.  Is there enough "Juice" for this?  (on a Chevy they say don't do this as the ICM likes a strong supply of 12V)

 

Are these Ignition Control Modules prone to failure? 

 

Should I switch the sparkplug wiring so that it fires first on the exhaust side?  I've read (here) that it runs better off w/the exhaust plugs firing 1st>

[datzenmike]

First stop buying things and putting them on. It's wasteful of money and time and more like trying to win the lottery. There are several thinge that can cause the tach to not work and they are much easier to fix. For example the tach is wireds to the intake coil... if it's not firing... no tach. Fix the firing and you fix the tach. Never throw away old parts.

 

Second, the intake and the exhaust plugs fire at ALL times. The only condition when the exhaust side is shut off is at full throttle when the vacuum drops below a set amount. A switch turns the exhaust side off. That's it.

 

You should have +12 volts on both coil positive terminals. Get a $5 test lamp and check that the light comes on with the ignition. If no power check or change the first fuse on the far left of the fuse box. It must have 12v on both sides of the fuse. Test for 12v on both sides of the 20 below. You don't have to remove the fuse to do this unless one side is dead. Ignition must be ON.

 

 

 

This is the power source for the exhaust side coil. Without power, no spark. There's no need to jumper and switch to fix. Everything should be there to make it work. Find the problem.