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iminhell 09-22-2012 04:20 PM

Alternator WOT switch?
Has anyone ever run into an issue where you can't disable the switch? (alternator cuts out at WOT even though you're commanding it to stay on)

Actually everything I tell the alternator to do isn't working quite right.
I'm telling the alternator to charge at 14.1 volts all the time. At idle with no accessories on it charges at 14 volts. When I turn the headlights on it drops to ~13.8-13.9 volts.
I replaced the wire from the alternator to the starter and from the starter to the battery the other day; larger gauge and known good wire/connectors. Voltage gained 0.1 volt from doing this; to where I'm at currently above.
The connector on the voltage regulator looks to be perfect. Wires aren't damaged or even stretched. Though it is the most likely culprit I can't find it to be bad.

Problems start around the 4,000 rpm mark, sometimes at part throttle and almost always at WOT.
I've adjusted the tune in various directions with no changes at all.

I'm curious if logging the alternator 'generator duty cycle' may shed any light on my issue? As in if it's near 100% most all the time the alternator is on the way out?

I'm at a loss here. Just tooteling around like a normal car everythings just fine. It's only when the car is pushed that this happens.

1turbofocus 09-23-2012 09:38 AM

What happens ? Normal charging systems is 13.6 to 14.2 so if your holding a 13.8 to 13.9 then your right where you should be

Keep in mind your voltage is going to the Batt , at the Alt you may see it doing the 14.1 but at the batt ( Batt hooked up ) it will always be lower


iminhell 09-23-2012 03:32 PM

These are voltage minimums:

It's very noticeable when it bottoms out. The dash lights dim a lot and a few times the headlights have turned off (Mach HID's).

I logged generator duty cycle last night but I've no clue if it shows anything useful. I had expected it to be a percentage much like injectors PW or fuel pump duty cycle, it wasn't. Most of the time it just read zeros. But near the times voltage was dropping it would register numbers; .3-.6 generally and only for a very short time. So I'm not sure if it even logs correctly.
Also the genDC and low voltage don't always correlate, actually the DC reads zeros more times than it registers working.

Here is the log (it's long, ~45 minutes) -->
Here is the tune file -->

badazz2010focus 09-23-2012 05:28 PM

voltage regulator? LOL somethings you cant over ride I dont think.

bespurcell 09-23-2012 09:28 PM

I have to agree with that^^. At idle the voltage regulator is only going to be able to do just so much.

iminhell 10-17-2012 11:27 PM

Got it solved.

You'll never guess what it was either.

OK. So I replaced the positive battery cable, improved the grounds and checked all the wiring. Same issue, though voltage was more stable. It still cut out WOT high RPM.
For some reason I played with the gauge cluster and ended up finding out somethings wrong with it. I swapped in the cluster from the other car and it works perfect. So the gauge cluster didn't dim anymore. The headlights still did though and logs showed a big voltage drop under the same conditions.

So today I'm going over what I can change in the tune and I come across something for the high speed fan under high load. I never noticed it before.
So I figure WTH, I'll adjust everything up and see what happens. High enough that it shouldn't kick in under heavy load ever.

And now voltage is good across the board. Weird.

I do think the alternator is a bit weak though. But this should prolong it somewhat.

El Gato 02-05-2014 06:45 PM

With regard to your 9/23 post about logging the generator duty cycle, I am currently looking at similar data. Most of the time it reads zeros, but spikes when anything increases load (headlights, power windows, applying brakes, etc). For me, we see the headlights pulse/dim a few times within a few seconds in parallel with the generator duty cycle. We've been troubleshooting alternator-related issues (new battery, new alternator, new connector soldered in). Did you ever get feedback about using the generator duty cycle as a tool for troubleshooting?

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