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86 rx7 no spark on leading coil

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Old Jun 14, 2013 | 08:09 PM
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From: christiansbutg va
86 rx7 no spark on leading coil

I just bought this rx7 and the fuel pump wouldn't run so I figured that's why it wasn't starting. So finally got it running and still no start. Got to checking and the leading coil has nothing coming out of it. Been looking for a couple hours on here and testing various things with no luck and more confusion. I'm very very new to wiring stuff and even new to using a multi meter haha. But I checked the black/yellow wire and it has 12 volts and I checked the black/white wire at the test port next to the leading coil and it has 12 volts. The green/yellow wire at the leading coil has nothing couldn't really find any info on what it's supposed to have. Checked pin 3i (black/white wire) at the ecu with the plug unplugged and it only has like .5 volts and I checked pin 2a and it had .5 volts also. Checked ohms of red and white wire and also blue and green wires and both sets had 160 ohms. Not really sure what this means or if it means anything. If anyone could possibly point me in the right direction it would be greatly apreciated!!! Thanks in advance
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Old Jun 15, 2013 | 08:11 AM
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From: christiansbutg va
Is there a way to check coil off the car? Also there's a relay laying in the car, is there any relay that controls the leading coil?
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Old Jun 15, 2013 | 10:15 AM
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From: tulsa,ok.
Chances are that the large plug above and to the right of the ECU called FEM-02 is not properly mated (mates the front and emission harnesses together.) FEM-01 and 02 are side by side and 02 is the smaller of the two plugs and has two B/W wires, one on top of the other. Both groups of B/W wires should have voltage w/key to on. If the ECU isn't powered up then the other pin you checked couldn't have proper voltage.

Last edited by satch; Jun 15, 2013 at 10:18 AM.
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Old Jun 15, 2013 | 10:39 AM
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From: christiansbutg va
Ok I'll check that this evening. I tested the coil after searching and searching on how and from what I read it checks good. I took it off and cleaned all the spots where it mounts and tightened everything up to insure it has good ground.
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Old Jun 15, 2013 | 10:47 AM
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From: christiansbutg va
So to check this, check and make sure there's 12 volts on the b/w on FEM-02?
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Old Jun 15, 2013 | 10:57 AM
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From: tulsa,ok.
Originally Posted by Sammy Epperly
So to check this, check and make sure there's 12 volts on the b/w on FEM-02?
You need to check both sides of the connector. If you have voltage at the B/W wire at the check connector by the leading coil then you should also have voltage w/key to on at the front harness side of 02 because it is the very same wire from the same harness. The likely problem though is this voltage is not making its way to the emission side of the harness at 02 which would explain why the B/W wire at the ECU is not powered w/key to on. The B/W wire at pin 3I comes from the emission side of the harness which mates w/the front harness.
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Old Jun 15, 2013 | 12:27 PM
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From: christiansbutg va
Ok I think I understand haha. To check the green/yellow wire going to the leading coil, do you hook multimeter to the wire and slowly spin the motor over by hand?
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Old Jun 15, 2013 | 01:25 PM
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Originally Posted by Sammy Epperly
Is there a way to check coil off the car? Also there's a relay laying in the car, is there any relay that controls the leading coil?
a relay in the car under the steering column runs the fuel pump though..has a yellow connector( I am sure)
Oh,in case I missed stuff,the coil must be ON the car when you test it.It needs to be grounded.
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Old Jun 15, 2013 | 01:30 PM
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From: tulsa,ok.
Originally Posted by Sammy Epperly
Ok I think I understand haha. To check the green/yellow wire going to the leading coil, do you hook multimeter to the wire and slowly spin the motor over by hand?
Yes, and w/key to on the voltage should read 0 volts and then briefly change to 5 volts before returning back to 0 volts.
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Old Jun 15, 2013 | 01:52 PM
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From: christiansbutg va
Yea the fuel pump relay was unhooked also when I got the car but I finally figured that one out. Ok I was testing resistance off the car. I'll try this out in a couple of hours and see what I come up with.
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Old Jun 15, 2013 | 05:02 PM
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From: christiansbutg va
I rechecked the green/yellow wire and it has .02 now and jumps to 5 when spinning the motor.
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Old Jun 15, 2013 | 05:17 PM
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From: tulsa,ok.
Originally Posted by Sammy Epperly
I rechecked the green/yellow wire and it has .02 now and jumps to 5 when spinning the motor.
Then it's doing what it is supposed to do.
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Old Jun 15, 2013 | 05:17 PM
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From: christiansbutg va
I checked the big plug next to the ecu and the black/white wires and they only have .4 on both sides of the plug, rechecked the black/white wire on the test port next to the coil and it had 12. Does any of this make sence? Haha thanks for all the help
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Old Jun 15, 2013 | 05:19 PM
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From: christiansbutg va
Also the coil checks 15 on t1 and t2, .3 on a and b.
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Old Jun 15, 2013 | 05:28 PM
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From: tulsa,ok.
Originally Posted by Sammy Epperly
I checked the big plug next to the ecu and the black/white wires and they only have .4 on both sides of the plug, rechecked the black/white wire on the test port next to the coil and it had 12. Does any of this make sence? Haha thanks for all the help
It would if you weren't using a proper ground for the meter when taking the voltage measurement. There is a solid Black wire in the larger plug next to 02 which is a ground or if you still have the ECU exposed you can use either of the front mounting bolts as a suitable ground.
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Old Jun 15, 2013 | 05:44 PM
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From: tulsa,ok.
Originally Posted by Sammy Epperly
Also the coil checks 15 on t1 and t2, .3 on a and b.
You're going to have to clarify what you mean here.
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Old Jun 15, 2013 | 08:39 PM
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From: christiansbutg va
Ok I'll try using those grounds tomorrow evening. I read online that you test them by using a multimeter on t1 and t2 and then what they called a and b (where the wires bolt on), and those were the readings I got which were within specs.
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Old Jun 16, 2013 | 07:01 AM
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From: christiansbutg va
If the two wires at the coil are getting the proper power and the coils not getting spark doesn't the coil or igniter have to be the problem? Also does anyone have a good picture of the coil mounted in the car because mine has 4 studs but it will only line up with three studs.
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Old Jun 16, 2013 | 12:05 PM
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From: tulsa,ok.
Originally Posted by Sammy Epperly
If the two wires at the coil are getting the proper power and the coils not getting spark doesn't the coil or igniter have to be the problem? Also does anyone have a good picture of the coil mounted in the car because mine has 4 studs but it will only line up with three studs.
You don't need all four bolts to ground the coil to the fender properly. Secondly, how are you testing for spark? The spark plugs and wires could be the issue. If you pull the wires off of the coil bore and place them closely next to the bore and attempt to start the car you should see sparks coming from the coil bore. If you don't see this then the coil/igniter is likely your problem. There is also the issue of voltage as the starting circuits including the ECU must see at least a certain amount of voltage to work properly. And did you ever get a proper reading from the B/W wires at connector FEM-02?
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Old Jun 16, 2013 | 01:10 PM
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From: christiansbutg va
Just sticking a screwdriver in the wire and look for spark. I'm working alone which makes checking things hard. I've been at work all day today but I'm going to try and test the b/w wires when I get off in a couple hours if the rain holds out. Thanks for all your help satch, glad there's someone on her knowledgeable and willing to help someone out, before I made this thread I was using another thread that you were posting a lot of useful info on.
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Old Jun 16, 2013 | 03:35 PM
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From: tulsa,ok.
Originally Posted by Sammy Epperly
Just sticking a screwdriver in the wire and look for spark. I'm working alone which makes checking things hard. I've been at work all day today but I'm going to try and test the b/w wires when I get off in a couple hours if the rain holds out. Thanks for all your help satch, glad there's someone on her knowledgeable and willing to help someone out, before I made this thread I was using another thread that you were posting a lot of useful info on.
If you look for spark as suggested and it is dark outside or in your garage then you can do this check even if you're alone.
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Old Jun 16, 2013 | 03:45 PM
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What's up guys,I'm new to the forum and still a "noob" when it comes to tuning so bare with me please, lol. I have a question for you, it's a two part question. First off I have microtech lt16 with a 1 bar map. My question is were can I get the 3 bar sensor to upgrade. My second question is can I run the electromotive DFU ignition System in conjuction with my microtech ECU.
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Old Jun 16, 2013 | 04:30 PM
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From: christiansbutg va
Ok I'll try to check that tonight when it's dark. Rechecked the b/w wires on fem-02 and 12 volt. Checked 3i and it has 12 volts and rechecked pin 2a and it has 12 unplugged and 5 plugged up. So it has to be for sure coil, right?
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Old Jun 16, 2013 | 04:36 PM
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From: tulsa,ok.
That or there's not enough juice to power the coils w/key to start.
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Old Jun 16, 2013 | 06:12 PM
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From: christiansbutg va
I got someone to crank the car while I put the plug near the bore and no spark. I have a battery charger hooked to it and its got like 14 or so volts going to the coil.
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