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Discussion Starter · #1 ·
Does anyone know what the voltage readings from the ECU to the pickup coil should be at the wire harness to the distributor?
I'm getting nine volts on each of the three wires from the ECU and that isn't right. (I don't think.)
My schematic doesn't give any voltage listing for that group of wires, however it seems that only the white wire should have voltage.
If someone could check theirs or if you have a manual with the voltage listing for this wire group, I would appreciate you assistance.
On my 84 the wire group is black, white, and red.

Thanks
 

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Discussion Starter · #3 ·
I have the ohms listings in my manual. I need the voltage at the harness from the ECU to the pickup coil in the distributor on the ECU side with the ignition in the on position. I am getting 9volts on all three wires. That doesn't seem right. If anyone could pop their hoods, get a volt meter, and take a voltage reading on the white, red and black wires on the ECU side of the harness, I would appreciate it.

Thanks
 

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Well the fact that you have voltage at all three wires is your problem. These wires are going to be inputs to your ECM. The two pick-up coils in your dizzy are magnetic sensors, and generate their own current. The ECM takes this current from the sensor as an input to either ground out the injector, or fire the coil.
Take note that the dizzy pigtail can mistakenly be connected to the Injector Resistor Pack, but still there will be NO voltage readings. (the two pigtails fit, but will be a different shade of yellow :SM130 (1):)

Whats the deal with your car anyway? (other than the 9 volts at the three wires)
Give some details, and what went wrong.

I had some problems with a ground cable recently, and my testing procedures may aid you somehow. Go to post #5
http://forums.celicasupra.com/showthread.php?t=51745
 

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Discussion Starter · #6 ·
After rebuilding my 84 5MGE:

I had it running good, not great, but good enough to take it for a break in drive.

As I was accelerating on a level grade the engine back fired loudly and died. The tach went to zero. I tried bump starting it with no joy.

So this is were I am...

Back in my garage, it cranks easily with good compression in all cylinders.

There is no spark until I release the ignition trigger, then there is a spark that lasts a second or two. The coil ignitor assembly make a buzzing noise and I can smell ozone. That means that there is a high volage arc.

So I replaced the coil and tested the igniter and all of the associated relays and fuses. Still the same spark situation. I replaced the ECU and ignitor with ones from a running 85. The ECU wire bundles pass the resistance checks listed in my manuals. I replaced the distributor.

Still, whenever I turn on the key, the coil/ignitor assembly make a buzzing noise with the smell of ozone. When the engine is cranking, there is no spark until after the cranking stops when there is a long, 1-2 second, spark.
 

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Do you have a check engine light on with the key off and OUT of the vehicle?
I had the same problem with the igniter making a "buzzing" sound, and smoking.
It ended up being a bad ground. (the one the runs along the injector harness and bolts to the intake manifold). It vibrated loose.
If you got the car to run, and all of the sudden it died, I bet you there was a loose ground that needs to be cleaned or tightened. I highly recommend you check them ALL.
I made a list of all the engine compartment grounds in my post I previously linked you to. Just give the thread a look over and see if you can find any tests that I provided, and try them out. There is a lot of information on specs and test procedures in there, and keep us posted.

As for you "releasing the ignition trigger"... what do you mean by that?
are you rotating the dizzy rotor?
 

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Discussion Starter · #8 ·
Air box removal is my next step

I installed a remote starter trigger for ease of trouble shooting. This way I don't have to get in the car to turn the engine over.

I am planning on taking the air box off to retrace my wire harness to make sure I didn't make any wrong harness connections or miss anything like a ground. Thanks, that's good advice.

If someone has a logic diagram for the ECU, I would be in your debt.

Thanks for your interest in my dilemma.
 
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