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Old 07-22-2018, 01:35 AM   #1
nathan.d.kim
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Default WOT Dash Lights Flicker

When accelerating at WOT my dash warning lights all flicker for a split second. They flicker for such a short time it is easy to miss. None of the lights stay on.

Could this be a normal by-product of increased NVH (hardened motor, trans, rear diff, and shifter mounts)?

I just replaced my battery with a Duracell ATM but the dash flicker still happens.

Alternator? Not really showing any symptoms of a bad alternator.

Planning to look up how to test the alternator and try that out. The current one was an uprated OEM one remanufactured by Maniac Electric Motors out of Dallas. But, that was about 6 years ago...

[FIXED] Replaced alternator.
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Last edited by nathan.d.kim; 10-02-2018 at 10:37 PM. Reason: Issue resolved.
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Old 07-22-2018, 05:36 PM   #2
Zmanwrx23
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bad ground?
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Old 07-22-2018, 10:39 PM   #3
nathan.d.kim
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Very possible. I'll take a look at that. I know I can buy my own wires, but I ordered a grounding kit from Flex Innovations to see if that will help solidify my ground throughout. I think the OEM design has a single point of failure. Car is 11 years old and I haven't touched the OEM ground cable/strap the entire time.
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Old 08-19-2018, 05:33 PM   #4
nathan.d.kim
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Installed the big three grounding kit from Flex Innovations that connects the strut tower (on painted surface) to the intake manifold, alternator, and battery.

Went through 5 tests for the alternator today and all the numbers are good (battery voltage with engine off, idle voltage, loaded voltage at 2000 rpm, negative voltage drop, and positive voltage drop).
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Old 08-19-2018, 05:46 PM   #5
nathan.d.kim
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Anyone know where all the ground points are on an 07 STI? With the big three kit, do you still need the regular ground points to be firm/clean, or does the add-on kit replace the oem ground strap?
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Old 08-20-2018, 10:45 PM   #6
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Tried to recreate the dash lights today and couldn't get it. What the heck?
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Old 08-20-2018, 11:39 PM   #7
Charlie-III
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Quote:
Originally Posted by nathan.d.kim View Post
Anyone know where all the ground points are on an 07 STI? With the big three kit, do you still need the regular ground points to be firm/clean, or does the add-on kit replace the oem ground strap?
Every OEM connection to be maintained. Better is remove, clean, dielectric greas, reattach.

Add img a ground to a painted surface sorta gives up some of the benefit of doing the connection.
Volts/amps prefer metal to metal, not metal to paint.
Yes, some OEM connections have paint in there.
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Old 08-26-2018, 02:49 AM   #8
nathan.d.kim
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Well, I think this issue has been resolved, finally. Positive battery terminal was a little loose, so the small bolt was tightened.

Also, I realized my 4-bar Omni Power MAP sensor does not seat all the way in the harness - no click. Stock one clicks in, so the harness is fine. Looking at the two sensors, it looks like the "teeth" on the Omni Power unit that click into the harness is a bit too far to click all the way. I put some zip ties on both sides of the MAP to keep the contacts secure.

The MAP contacts appear to have been jostled by motor vibrations at WOT but only intermittently. Hardened motor, tranny, and differential mounts must cause more vibrations than normal.

Car is not jerking on 2nd gear now and holds throughout the power band.
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Old 08-30-2018, 01:49 AM   #9
Cougar4
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The warning lights are tied into the field circuit of the alternator so they can be tested when the ignition is On and the engine isn't running. If the problem returns I would check out the alternator and the wiring to it.
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Old 09-24-2018, 10:18 PM   #10
nathan.d.kim
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Quick update to this thread: I replaced the alternator with an OEM replacement from Maniac Electric Motors. This appears to have finally resolved the flickering dash lights, hesitation on 2nd gear, and really smoothed out the throttle response. I had no idea the old alternator was bad since various multimeter tests showed the alternator was fine. Live and learn. The old one must have had a bad diode or was starting to give way more and more (hence, the increasing frequency of the flickering and hesitation).
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Old 09-26-2018, 03:38 PM   #11
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You are correct about the diodes. As more diodes fail the DC ripple voltage gets greater, and the dash lights are the easiest way to see that take place.
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Old 09-26-2018, 04:41 PM   #12
Charlie-III
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Quote:
Originally Posted by Cougar4 View Post
You are correct about the diodes. As more diodes fail the DC ripple voltage gets greater, and the dash lights are the easiest way to see that take place.
Minor correction, I think.......as the diodes fail, the AC ripple increases, thus creating issues.
Just my thoughts.......
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Old 09-27-2018, 11:03 PM   #13
nathan.d.kim
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Quote:
Originally Posted by Cougar4 View Post
You are correct about the diodes. As more diodes fail the DC ripple voltage gets greater, and the dash lights are the easiest way to see that take place.
Quote:
Originally Posted by Charlie-III View Post
Minor correction, I think.......as the diodes fail, the AC ripple increases, thus creating issues.
Just my thoughts.......
Thanks, guys. I'm just glad to have gotten this sorted out. I had a feeling it was the alternator, but wanted to rule out minor issues with cheaper mods (big-three grounding kit) and more thorough inspections.

Last edited by nathan.d.kim; 10-02-2018 at 10:36 PM.
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