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post #1 of (permalink) Old 12-27-2001, 07:58 PM Thread Starter
 
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Tr ignition desperation!!!

Hey all!

I did the TeamRush upgrade on my 76 cj-5 a few years back and it runs flawlesly! But I helped a friend shoehorn a 360 in his 92 yj. we wired his jeep much like mine but his EATS modules like there is no tomorrow!!! The modules warm up and then shut down....sometimes they start up again. We grounded everything we could get our hands on...module...coil...solenoid...all to the batery. We looked at the difference in voltage beteen his and mine and there is only a slight difference (1.5v) We used new wires everywhere, a resistance before the coil. The only big difference is that I an using my ignition switch from the collumn and he uses toggle switches. I am seriously running out of ideas Help!!! The wires match, the voltage matches, so why doesnt it work?
we are using a ford module, should we use a jeep module (I thougt they were the same) Is there resistance somewhere!!! AAAAARRRRRGGGG!!I need a beer!

Sorry for the long post!

Ben
I also got a shock from the coil WOW!

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post #2 of (permalink) Old 12-27-2001, 09:40 PM Thread Starter
 
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Re: Tr ignition desperation!!!

Oh well I hate begging but here goes! Helllllllp! I'm sure someone has an idea that I haven't thougt of?

Ben

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post #3 of (permalink) Old 12-27-2001, 10:07 PM
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Re: Tr ignition desperation!!!

<font color=red>What's the DC voltage on the coil in the run mode (engine not started)?</font color=red>
That 1.5 volt difference may not seem a lot, but it can make a difference between life and death for the module. That resistance (ballast or resistor wire) had best measure 1.35 ohms.... or figure out the resistence needed due to the resistance of your coil if it's aftermarket.

<font color=red>Did you use the "blue" grometted FOMOCO ignition module?</font color=red>
The Duraspark ignition modules for the I6 and the V8 ain't no different. All it does is work a little harder for the V8 as opposed to the I6 because it's pulsing for two more sparkplugs.

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post #4 of (permalink) Old 12-28-2001, 07:50 AM Thread Starter
 
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Re: Tr ignition desperation!!!

Thanks Leve,

I'm using the tfi coil and a wells module (canadian tire) the module is not as square as my module, I think it was for a mustang 5.0HO. Could that make a difference? I'm off to the garage and I'll check the resistance and the voltage on the coil.Thanks again!

Ben

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post #5 of (permalink) Old 12-28-2001, 08:05 AM
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Re: Tr ignition desperation!!!

TR'd be cussin' ya out for using Well modules. They're not the best in the marketplace, but they are avaliable. That could be the problem, but I doubt it yet....

Make sure the run voltage is no more than about 8.5 volts... I suspect that's thje problem and you'll have to modify the resistance to lower the voltage. I that is the problem, even a Wells module should last a good long time... mine lasted on average about six years before dying.

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post #6 of (permalink) Old 12-28-2001, 08:17 AM Thread Starter
 
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Re: Tr ignition desperation!!!

Sorry TR but the wells was cheap and came with a lifetime warranty!

Anyways, the voltage to the module, both red and white is at about 12.75v and at the coil it's about 9.5v at idle and climbs to 13.5v at higher rpm's. But both Jeeps do it, my module stays cool and has beer running forever and his heats up and shuts down after about 10 minutes???

Thanks Leve

Ben

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post #7 of (permalink) Old 12-28-2001, 08:48 AM
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Re: Tr ignition desperation!!!

humm. climbs with RPM? I've never noticed that.... I have to check that out. I'd peg that to Pulsing and how the meter reacts... not a true DC voltage increase.

What we're interested in is the DC voltage applied to the coil in the run mode. It can, and should be measured, with the engine not started, but the ignition switch moved to the run position. This swtiches in the ballast resistor, or the resistor wire, to feed DC to the coil. At this point, if the voltage is above 8.7 , or so DC volts, the module will start to overheat. The speed of the disruction will be proportional to the overage amount of the voltage.

Just out of curisoity, when the Jeep's running at a higher RPM, what's the measurement at the battery? If it's more than about 13.7 volts then the alternator is over charging... and "over volting" the electical system. If this happens, the alternator/regulator may be part of the problem.

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post #8 of (permalink) Old 12-28-2001, 11:36 AM
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Re: Tr ignition desperation!!!

Leve is correct regarding the voltage. To get an accurate reading you really need a true RMS meter or use and Oscope. The voltge to the coil is a pulsing voltage...or in reality a pulsing ground...kinda.......the output of the module to the coil is anctual a solid state transistor that shorts to ground (almost) and causes the pulse in the coil. Remember, you have a positive voltage in one side of the coil, and the module shorts out the other side with pulses from the transistor (most likely and PNP). You can simulate the same thing by just connecting a ground to the neg side of the coil and then removing it. When you remove it, the coil will spark.
Now that we have that out of the way...the transistor in the module can only handle so much current. If the voltage drop across the coil is not enough, the transistor has to drop the voltage, hence it gets too hot. With the ignition on but the engine NOT running, measure the voltage on the pos side of the coil and compare it to your good jeep. I bet you need a resistor between the bat and the pos side of the coil. To be sure of the voltage drop, disconect the ign module and short the neg side of the coil....then measure the voltage on the pos side. On your good jeep, I bet it will be less then the bad one.
One the older GM cars (I bet Leve will remember this), you had 2 wires going to your coil. One was through a resistor that droped the voltage to about 8 volts, the other went to the starter solenoid. When you were starting your engine, the voltage from the starter sol was a full 12 volts, this gave you more spark for starting...once you backed off the key to the normal ign position, then you only had 8 volts going to the coil...thus the voltage was spark was smaller but your points (yes, points) lasted a lot longer. An old racing trick was to run a wire from the bat to a switch and then to the coil. When you had a race (and of course, I never raced on the street) you flipped the switch for a little extra power. Made a difference on high compression engines.

Let us know what you find.

John...southern CA
84CJ7, 3"lift, 32"BFG, 4.10's, ARB Rear, Detroit Front, Solid Axle's, Durabak, York Air

They say we learn by our mistakes......I guess thats why we are all so smart.
post #9 of (permalink) Old 12-28-2001, 12:01 PM Thread Starter
 
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Re: Tr ignition desperation!!!

Thanks for all the info guys, I am printing the stuff, grabbing a bite to eat and then back to the garage....someday I'll have a "compooter" at the garage!!!

Ben

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post #10 of (permalink) Old 12-28-2001, 12:20 PM
 
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Re: Tr ignition desperation!!!

My guess is some how or another you have managed to ground one of the power wires to the module.
Both red and white wires get power, one while cranking, one in the 'RUN' position, but neither get grounded.
Grounded power wire is the only thing I know of that will 'EAT' modules as fast as you can install them.
Check your two wire connector (harness side) for a ground, those two wires shouldn't be grounded.

The black wire on the 4 wire connector is the only one that needs to be grounded.

So many cats, so few recipes...
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