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No power to three of four coils

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Old 07-17-2014 | 06:00 PM
  #1  
derf360's Avatar
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From: Lakeville, MN
Fixed: No power to three of four coils

So...I need help... I thought my coils went to ****(BHR), checked spark, would only get spark on the front trailing coil.... Rest of coils wouldn't work in OEM spot on the engine wiring harness... Swapped them into the front trailing position using thre engine wiring harness, they get spark... So... Why would one coil receive power from the wiring harness but not the other three? Any thoughts, ideas would be help full...

Other question is does anyone know where those wires originat from to chase them down...

I have used the search button and have found nothing relevant, this is my first time starting it up... I have reset the ESS... I also have a Cobb access port....

I get a check engine light flash for a few seconds after attempting to start the car... Nothing shows up on the Cobb for a code....

Update(7/20/14): FL coil strong, FT kinda weak, RL & RT coil dead...

How do I know this you may ask... I plug the FL coil pack into the engine wiring harness to all four positions and it fires spark out like no other... So, new coils will be on the way... Not exactly happy with the everlasting solution, but **** does happen and wear out...

Update(7/23/2014):
Car runs now with new set of coils...

Steps to follow to trouble shoot this problem..
1) pull your hair out and cry
2) pull the fuse/relay for the fuel
3)label wiring harness, plug wires, coils
4) pull spark plugs
5) reconnect plug to plug wire/coil you want to test
6)ground out the spark plug(I went to the throttlebody)
7) have a helper turn the car over and watch for spark
8) figure out which coils create spark and which don't and label them(good/bad)
9) disconnect them from the engine wiring harness
10) plug the good coils into the bad positions and retest for spark
10.a) if you have good spark, you have a bad coil
10.b) if you cannot get spark with the good coil in the position of the bad coil, check for continuity in the wire leading from the PCM/ECU to the plug for the coil(not sure where I got the PDF for the wiring manual) and check the other wires in the plug for continuity (from what I understood from the wiring diagram they are grounded out eventually, I may be wrong), if you cannot get any readings of resistance you have a cut wire and happy hunting, if you do get readings recheck all your connections and recheck for spark...
11) buy new coils and correct plug wires and hope to baby Jesus your car starts, otherwise there are other issues...

2004 MT GT

New pettit racing engine(0miles)
Bhr coils(15k miles)
New starter(0miles)
2 yellow top batteries(relocation to trunk)
New spark plugs
Taylor "409" Spiro race wire,10.4mm plug wires
Sohn adapter
Aem intake
Ron Davis radiator
Remedy water pump
Greedy oil pan
Oil filter relocation
Fuse are good
Borla catback exhaust
But engine mounts
Bhr mid pipe catless
Bhr flywheel
Act counter weight
Act clutch and pressure plate
Cobb Access Port
Air pump removed
Oil breather
Attached Thumbnails No power to three of four coils-img_20140717_170113.jpg  

Last edited by derf360; 07-23-2014 at 11:30 PM. Reason: updating more info as I remember it...
Old 07-17-2014 | 07:29 PM
  #2  
MazdaRX8Lover's Avatar
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Ok so I know nothing about cars, however I have 8 years + in electronic engineering. Based on the diagram I see it is set up in parallel, my thought is the positive (or negative, whichever is represented by the wire on the top) may have a break after the fist one but before the second. My thought is to try a continuity test of that wire and check for a bad connection. I hope this helps, and if not, please don't hate me hahaha. Best of luck!
Old 07-18-2014 | 12:02 AM
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I got a call back from Gavin? At Pettit Racing while I was taking a nap, he said to check the plugs at the ecu and make sure they are plugged in all the way... They are.. I cleaned them with contact cleaner and still nothing....
Old 07-18-2014 | 01:23 AM
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From: Bay City Tx
check continuity across the 12volt line to each coil and across the ground line to each coil. That will let you know if it's the ecu or an actual power problem. Everything should be shared between the coils except the ECU signal.
Old 07-18-2014 | 08:56 PM
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The wires are good running from the back of the ecu/pcm to the coil plug ins... Sooo....?

The pins on the back of the ecu look fine, not bent or showing signs of wear, same thing with the female plug going into the ecu...

Going to retest for spark from the coils and see what happens...
Old 07-19-2014 | 10:18 PM
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Taylor "409" Spiro race wire... 10.4mm... Bought from Jegs part#895-79688

Last edited by derf360; 07-19-2014 at 10:25 PM.
Old 07-20-2014 | 09:27 PM
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Updated... Bad coils....

In their defense... The worked all the way up through the engine failure... They have been sitting since October of 2013... They even would start the car with the blown apex seal...
Old 07-22-2014 | 04:56 PM
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Can I get an explanation on why they don't work please?
Old 07-23-2014 | 11:11 PM
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I see what you mean... I had the MSD wires still, hooked them up and still had no spark from the other two coils, still a weak spark from one and good spark from the other.... Hooked up my new coils and the car started on the first few cranks... So.... I'm happy my car moves with a few oil leaks from the oil filter relocation kit.... And an exhaust leak... But other than that, all is good...
Old 07-23-2014 | 11:19 PM
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TX

Oh boy. Glad it is running.
Old 07-24-2014 | 07:02 PM
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Didn't realise there was a warranty on them... And I wanted it running so just purchased some new ones to get it on the road...

"The pre-assembled kit contains a baseplate, coil brackets, ignition coils, a plug-and-play conversion harness, and custom-built MSD spark plug wires. It also includes a 1-year warranty on all parts, materials, and workmanship"-pulled from the BHR websites...

I have had mine over a year now, two to be exact... So I wouldn't be covered under the warranty...

Last edited by derf360; 07-24-2014 at 07:06 PM.
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