G35 Coupe V35 2003 - 07 Discussion about the 1st Generation V35 G35 Coupe

Bank 1 coil packs with weak spark?

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Old Apr 16, 2018 | 11:59 AM
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Bank 1 coil packs with weak spark?

After doing a valve cover gasket on the driver side,my car came up with a P0300 (random/multiple misfire)code. I tested all the brand new sparkplugs I put in, and they checked out. Then I checked to see if the coils were the problem. All of the coils on the PASSENGER side have very little spark/no spark at all (its random) I switched 2 of the coils to the other side to make sure all 3 hadnt gone bad, and they had perfect spark on the driver side. Ive tried following the harness to all the spots it connects and everything is hooked up right.... Has anyone ever had this problem?
 
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Old Apr 16, 2018 | 12:14 PM
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So you replaced the driver side valve cover and you're having problems with spark on the passenger side? Did you remove any wires from the passenger side? It's not uncommon to hear about misfires after doing this project but it's almost always the wire harness connected to the wrong packs. The harness for the coil packs should have numbers 1-6 on each connector so you can't connect them wrong. Make sure you hear a *click when connecting them
 
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Old Apr 16, 2018 | 12:18 PM
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Originally Posted by FreshLikeAG
So you replaced the driver side valve cover and you're having problems with spark on the passenger side? Did you remove any wires from the passenger side? It's not uncommon to hear about misfires after doing this project but it's almost always the wire harness connected to the wrong packs. The harness for the coil packs should have numbers 1-6 on each connector so you can't connect them wrong
All the coils are hooked up correctly. Ive been driving myself nuts trying to figure this out lol. I tested the spark on all of the coils and the entire side just gets super weak spark. My best guess so far is that a ground somewhere is messed up. The other huge problem is finding a diagram to use
 
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Old Apr 16, 2018 | 12:24 PM
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I'm still inclined to think something didn't get reconnected. Did the harness have numbers for each coil pack? It's very common to hear people connecting the wrong plug to the wrong pack. You hear about it when people change their spark plugs.
How much of the harness did you remove?
Don't forget about the 2 plugs around the throttle body(behind)
Check your pcv hoses
 
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Old Apr 16, 2018 | 01:01 PM
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Originally Posted by FreshLikeAG
I'm still inclined to think something didn't get reconnected. Did the harness have numbers for each coil pack? It's very common to hear people connecting the wrong plug to the wrong pack. You hear about it when people change their spark plugs.
How much of the harness did you remove?
Don't forget about the 2 plugs around the throttle body(behind)
Check your pcv hoses
I completely undid the harness on the driver side and just moved it out of my way onto the top of the passenger side. Everything is connected back the way it should be (to my knowledge). Again, all 3 coils on the passenger side have VERY WEAK SPARK. My best guess to this point is that there is resistance somewhere.
 
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Old Apr 16, 2018 | 01:25 PM
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Front and rear cameras, tire pressure for all four tires can display on screen,folding side view mir
^

Test the resistance of the coils/wires on the drivers side with an ohm meter and compare the result with the readings on the passenger side.
3 coils/wires with a shorted winding? Unlikely but possible.

Telcoman
 
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Old Apr 16, 2018 | 09:45 PM
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Originally Posted by telcoman
^

Test the resistance of the coils/wires on the drivers side with an ohm meter and compare the result with the readings on the passenger side.
3 coils/wires with a shorted winding? Unlikely but possible.

Telcoman
I checked all the grounds I could find and they were all okay... Ill test the Ohms tomorrow and see if i find anything 🙏
 
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Old Apr 17, 2018 | 12:50 PM
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There aren't individual grounds for the left and right side of the engine however there IS a splice in the harness that you probably need to fix, once they're all soldered together they eventually land on the timing chain cover at the top, those are the F22 and F23 termination points, if you have a 6MT you will only have ONE termination point because the other goes the the 5AT. I would start by cleaning up all the grounds back to the battery, from F22/23 there is another larger gauge jumper on the passenger side of the timing cover that goes to the chassis below the coolant reservoir, remove the single 10mm bolt holding the reservoir down and lift it straight up to access, leave the hose attached. Finally the battery negative terminal has a short jumper to the chassis in the battery compartment, remove the entire plastic cover not just the access window.

Unbolt every connection, clean with a steel wire brush on the bolt threads and lug, apply electrical anti-oxidation grease DE-OX and reattach the bolts. This will eliminate any resistance from the lugs, however I think you have a soldered joint from F22/23 inside the taped harness to the coil packs on that bank, you can TEST this by unplugging the coil packs and reading resistance back to F22/23 with a digital multimeter, you should have ZERO (meter sometimes reads 1) ohm of resistance to ground.
 
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Old Apr 17, 2018 | 12:56 PM
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Also, you did have to unplug connector F201 I think and it's possible you didn't plug it in properly, if you have bad spark on plugs 1,3 but plug 5 has normal spark then that's exactly what is screwed up.

 
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Old Apr 17, 2018 | 01:08 PM
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Youre a life saver lol. Im looking now and looks like I have to take the plenum off again. Thanks for youre roly, Ill respond with how it goes.

QUOTE=cleric670@gmail;7136688]Also, you did have to unplug connector F201 I think and it's possible you didn't plug it in properly, if you have bad spark on plugs 1,3 but plug 5 has normal spark then that's exactly what is screwed up.

[/QUOTE]
 
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