no output from my 5 pin ecu
- Thread starter cuda guy
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Professor Fate
Push the button, Max...
Which EZ Wire kit did you use? The ones I've seen are pretty generic, based on GM components.
That said, it depends on how you wired it- most aftermarket harnesses and schematics for Mopars are based on 4 pin ECUs. Re-check the diagram you used- four or five wires into the ECU plug? A 4 pin ECU will work in a 5 pin harness, but a 5 pin ECU will not work in a 4 pin harness.
That said, it depends on how you wired it- most aftermarket harnesses and schematics for Mopars are based on 4 pin ECUs. Re-check the diagram you used- four or five wires into the ECU plug? A 4 pin ECU will work in a 5 pin harness, but a 5 pin ECU will not work in a 4 pin harness.
Its my understanding the 5 pin was discontinued a very long time ago. The 5th pin function is now within the ecu itself.
67Dart273
Well-Known Member
The "yellow wire" is most likely wrong. DO NOT connect that to the starter relay. Tha wire should go to the original ballast terminal that was the brown spliced with the coil+ wire. I DOUBT that yo actually really have a 5 wire ECU, as others have mentioned
THIS DIAGRAM IS WRONG in most contexts:
67Dart273
Well-Known Member
If you look at these you will see that the ignition resistor wiring is THE SAME as it was for breaker points, and the 4 pin resistor is that same way for the COIL side on the RIGHT side of the resistor. On the 4 pin resistor wiring, the LEFT side of the resistor ONLY powers the 5 pin box but MOST 5 pin boxes are in reality a FOUR pin box and do not need that wire
There is a wire MISSING in both diagrams. On the top diagram, there should be a wire going to the coil+ side of the resistor, BROWN, that is FACTORY. LEAVE that in place. That is your coil "bypass" circuit, and is what IS SUPPOSED to be in place of the WRONG yellow wire. AGAIN that wire IS FACTORY and it DOES NOT go to the starter relay as the other diagram states
There is a wire MISSING in both diagrams. On the top diagram, there should be a wire going to the coil+ side of the resistor, BROWN, that is FACTORY. LEAVE that in place. That is your coil "bypass" circuit, and is what IS SUPPOSED to be in place of the WRONG yellow wire. AGAIN that wire IS FACTORY and it DOES NOT go to the starter relay as the other diagram states
67Dart273
Well-Known Member
If I am incorrect about how you have it wired, please post the diagram you are using.
A couple quick checks:
1.. THE ECU BOX MUST BE GROUNDED
2..."Hot wire" power to the coil+ with everything connected
3...Disconnect the distributor trigger connector. Take the end leading to the ECU harness and repeatedly tap the bare connector terminal to ground. Each time you do that should give you 1 sharp blue "snap" spark out of the coil wire
A couple quick checks:
1.. THE ECU BOX MUST BE GROUNDED
2..."Hot wire" power to the coil+ with everything connected
3...Disconnect the distributor trigger connector. Take the end leading to the ECU harness and repeatedly tap the bare connector terminal to ground. Each time you do that should give you 1 sharp blue "snap" spark out of the coil wire
Between 67Dart273 and Halifaxhops, they have the answer. Calling Hallifoxhops??????
67Dart273
Well-Known Member
^^Easy. The path for coil current is key--through bulkhead---to ballast--to coil+ and through coil--and coil - goes back to the box and ground (Actual electron flow is opposite direction but I just mean "function"--describing the path.
So with the key "on" in "run" current flows through the coil. This means that coil voltage DROPS due to current through the ballast resistor, so check coil + reading---with key in "run" the coil should be around 6-8V or so, and NOT "same as battery"
If coil + is "same as battery" with key on, it means there is no current being drawn---which means either the box is not grounded, or the box is bad, or the box itself is not getting power--or the coil is open
Now measure coil- (NEG) It should read quite low, 1-2V which shows the box is "holding" the coil neg terminal "close to ground." If that terminal is 0, the coil is open or some issue no power to the coil. If it is same as battery, see paragraph above
So with the key "on" in "run" current flows through the coil. This means that coil voltage DROPS due to current through the ballast resistor, so check coil + reading---with key in "run" the coil should be around 6-8V or so, and NOT "same as battery"
If coil + is "same as battery" with key on, it means there is no current being drawn---which means either the box is not grounded, or the box is bad, or the box itself is not getting power--or the coil is open
Now measure coil- (NEG) It should read quite low, 1-2V which shows the box is "holding" the coil neg terminal "close to ground." If that terminal is 0, the coil is open or some issue no power to the coil. If it is same as battery, see paragraph above
67Dart273
Well-Known Member
Copy of old post..........
Here's a post I made about the simplest way I know to get across testing the ECU/ ignition parts
You need a coil, the ECU and the distributor
Lay it out on the bench. Follow the diagram. Find the two distributor pickup terminals on the ECU. Hook them to the distributor
Hook the ECU case to battery NEG
Coil does NOT need grounded
Distributor does NOT need grounded.
Hook coil + to the power lead terminal on the ECU. Get a clip lead hooked there and let dangle. This is your battery "hot" when you are ready
Hook something from coil "case" to a probe for testing spark.
Hook up your power clip lead. Twist the distributor shaft while holding the test probe near the coil tower. The thing should make sparks
If not, unhook distributor. Take first one, then the other pickup clip leads, and "tap tap" ground them at the battery connection. Coil should make 1 spark each time you do so.
If not, try another coil. If that does not fix it replace the ECU
IF you hook it all up and it WORKS, then there is something AFU in the car harness. SUSPECT a bad ECU connector OR a bad DISTRIBUTOR connector
=============================================
This is all you need to test the basics of the ignition. You can easily test the ballast separate. A battery, the ECU, distributor and a coil, and of course some test leads
Below, the basic diagram for a 4 pin ECU
Below, the wire for testing spark. I use my 12V test light. No, LOL the spark won't blow up the bulb
Below, the ground connection. ALL you need is one wire from batt NEG to the ECU case
Below, the two distributor connections. In the car these are polarity sensitive, but for testing does not matter
Below, the coil NEG connection
Below, battery PLUS connection, one wire to this terminal of ECU and jumpered over to + side of coil
Below, all hooked up and ready to test (except for battery ground). Should produce sparks at least 3/8" and typically 1/2" long
Below, distributor "one wire" test. I have removed the other distributor wire for simplicity. Take the bare connector end or this clip lead (the yellow) and with everything hooked up, ground it repeatedly. Each grounding should result in a spark (In this photo you need to hook up the ECU ground wire, I left it off for the photo)
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Here's a post I made about the simplest way I know to get across testing the ECU/ ignition parts
You need a coil, the ECU and the distributor
Lay it out on the bench. Follow the diagram. Find the two distributor pickup terminals on the ECU. Hook them to the distributor
Hook the ECU case to battery NEG
Coil does NOT need grounded
Distributor does NOT need grounded.
Hook coil + to the power lead terminal on the ECU. Get a clip lead hooked there and let dangle. This is your battery "hot" when you are ready
Hook something from coil "case" to a probe for testing spark.
Hook up your power clip lead. Twist the distributor shaft while holding the test probe near the coil tower. The thing should make sparks
If not, unhook distributor. Take first one, then the other pickup clip leads, and "tap tap" ground them at the battery connection. Coil should make 1 spark each time you do so.
If not, try another coil. If that does not fix it replace the ECU
IF you hook it all up and it WORKS, then there is something AFU in the car harness. SUSPECT a bad ECU connector OR a bad DISTRIBUTOR connector
=============================================
This is all you need to test the basics of the ignition. You can easily test the ballast separate. A battery, the ECU, distributor and a coil, and of course some test leads
Below, the basic diagram for a 4 pin ECU
Below, the wire for testing spark. I use my 12V test light. No, LOL the spark won't blow up the bulb
Below, the ground connection. ALL you need is one wire from batt NEG to the ECU case
Below, the two distributor connections. In the car these are polarity sensitive, but for testing does not matter
Below, the coil NEG connection
Below, battery PLUS connection, one wire to this terminal of ECU and jumpered over to + side of coil
Below, all hooked up and ready to test (except for battery ground). Should produce sparks at least 3/8" and typically 1/2" long
Below, distributor "one wire" test. I have removed the other distributor wire for simplicity. Take the bare connector end or this clip lead (the yellow) and with everything hooked up, ground it repeatedly. Each grounding should result in a spark (In this photo you need to hook up the ECU ground wire, I left it off for the photo)
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Uhm I will get crap for this but you will get shocked touching the transistor on top if is not a knockoff. Take a meter from the ecu case to a known good ground it should read zero ohms. Make sure the wire you are using for hot has powere in both the start and the run position. Did you use a distributor kit? Also can you post a pic of the ecu. New orange boxes are crappy, wont be the first new one that has failed.
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Not to be a dick, but if I have a signal generator and an O'scope, could you give me more detailed test parameters, please? After my son's 1993 SC300, I bought a scope. I'm an old crypto tech, so I know how to use one correctly. I thank you for your time.
Here is a good video.
67Dart273
Well-Known Member
Pretty good, BUT couple things:
Don't check spark with the existing coil wire especially a resistor/ supressor wire. Use a SOLID core wire with the spark tester
"No reason to remove cap." Yes there is. LOTS of these have debri/ rust/ etc caught up in the pickup / reluctor, inspect it for shaft play and reluctor strike damage. Also ALWAYS inspect the cap and rotor for carbon tracking and rotor punch through as well as "general" conditon......ESPECIALLY on a boat, LOLOL moisture in the cap!!!
I was not aware of the .2V AC "spec" on the pickup output wonder where he got that, and was not aware that a 5 pin would run with a bad seconary ballast. "I wonder" if that box is really a 4 pin box? (You can not tell by looking as many 4 pin boxes HAVE 5 physical pins)
Don't check spark with the existing coil wire especially a resistor/ supressor wire. Use a SOLID core wire with the spark tester
"No reason to remove cap." Yes there is. LOTS of these have debri/ rust/ etc caught up in the pickup / reluctor, inspect it for shaft play and reluctor strike damage. Also ALWAYS inspect the cap and rotor for carbon tracking and rotor punch through as well as "general" conditon......ESPECIALLY on a boat, LOLOL moisture in the cap!!!
I was not aware of the .2V AC "spec" on the pickup output wonder where he got that, and was not aware that a 5 pin would run with a bad seconary ballast. "I wonder" if that box is really a 4 pin box? (You can not tell by looking as many 4 pin boxes HAVE 5 physical pins)
67Dart273
Well-Known Member
What I was getting at is specifically the problem at hand---that a timing light seems to indicated dropped triggers. A scope monitoring the coil NEG line should tell you that, looking at the primary pattern
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