Doppelgänger

iTrader: (12)

Dunno. Didn't consider that. I somehow got this notion that there is a correlation between the jumpy voltage, jumpy AFRs (which I know for a fact should not be all over the place...and the last times the WB has failed, it wasn't causing fluctuations on the readout) and the radio cutting out as being related :/

I actually have been on the hunt for a replacement Bose unit...but this might speed it up.

Reverant

iTrader: (10)

Is the jumpy voltage issue a new thing or was it like that pretty much ever since you upgraded to the 2.7?

Doppelgänger

iTrader: (12)

I dont remember it before. Pretty sure I don't have any logs where I had batt volts being recorded. Be nice if someone else with a Hydra puts some info in as to what they see. I should probably post in the Hydra forum for that lol. I'll be calling FM/Jeremy tomorrow to run a few things by him.

patsmx5

iTrader: (16)

No worries man! Electrical problems suck to diagnose. Take all those measurements with a multi meter and post the numbers. You have 3 different issues, it's very likely there is 1 thing causing all of them vs all 3 things failing at the same time.

Doppelgänger

iTrader: (12)

Waiting on a friend to bring a multimeter over.

However, after the car sat all night, a few minutes ago I plugged the laptop in, turned the key on connected to the ECU and the batt was at 12.2v and dropped to 11.98v where it held steady for 10min before dropping to 11.96v. I think the battery is ok. But the other day, after a long drive, I watched that number drop to 11.2/10.98 after letting the car sit with just the key on in about the same amount of time.

Reverant

iTrader: (10)

That's either the alternator or the Hydra not controlling the voltage or a loose connection somewhere.

Doppelgänger

iTrader: (12)

AFAIK the alternator is original...with almost 190k on it....which is also another reason my logic suspects it.

I have never had to do anything with the Hydra controlling the alt., so my thinking is that since I never have before, there is nothing to look into with the Hydra to adjust.

Rallas

iTrader: (9)

I have had two alternators display this behavior just before failing. One of them just crapped out a week ago.


I would notice voltages bouncing up and down 0.5-1V at steady loads and speeds, worse when accelerating. Usually I don't see more than 0.2-0.3V ripple. This past time I only noticed the voltage swings a few days before it stopped charging completely.


I have never had it cause issues with electronics on the car while the engine is running. If it fails and eventually depletes the battery enough I can have re-start issues due to too low voltage.


I am dealing with NA, non ECU controlled alternators though.

concealer404

iTrader: (3)

In my experiences, the stereo will cut out on an NB if it sees an overvolt scenario, and the voltage is lower than you'd expect. I told Mike to post this here, as i had exactly the same symptoms on my MSM when it had a Hydra on it. It was nearly impossible to get the damn thing to be controlled properly.

aidandj

iTrader: (5)

<p>Maybe try and find one of westfields alternator control boards and hook it up.</p>

concealer404

iTrader: (3)

If he's going to keep Hydra and is going to modify anything, it should be to skip straight to an NA8 alternator. Do not pass go. Do not pass $200.

Doppelgänger

iTrader: (12)

What's better about the NA8 alt over the NB2? Genuine curiosity.

Up until last week, I've never had an issue like this. So I'm not faulting the Hydra, but do want to find what is failing.

Last night driving...well, sitting in stopped traffic for like 45 min, the idle was fluctuating, even after finally moving and driving several miles. On my way to work this morning, I have my parking/fog lights on and when I was stopped and had the blinker on, idle would fluctuate a couple hundred RPM....definitely not something it has done before. At this point, I'm just looking to buy a new/lightly used Mazda alternator and swap it out.

I have to drive across town after work, I'll do so with the lights on and whatnot. When I get close to my destination, I'll connect the Hydra and see what it is doing.

codrus

NA8 alternator is internally regulated, no computer control needed. You need to make some minor wiring changes to get it to run, though.

My experience with the Hydra 2.5 is that alternator control was pretty all over the place between 12.5 and 15, but it never actually went high enough to get my stereo to shut down.

JasonC has an analog control circuit for the NB alternator that works pretty well and is easy to build. That's probably easier/cheaper than buying an NA8 alternator just to avoid the PID tuning in the Hydra.

--Ian

aidandj

iTrader: (5)

<p>That's what I referenced with Westfields alternator board.</p>

patsmx5

iTrader: (16)

The older alternators react faster as they are internally regulated. You'll never see them wander from target like the stock alternator does with the stock ECU.

I would not change the alternator until I diagnosed the problem. That said, I have a used stock 70A alternator from my 99 I might would part with (but high mileage, I recommend you not buy it for this reason), and a brand new in box NA alternator I would for sure part with if you want to buy it. I ended up installing a chevy 1 wire 220A alternator on my car so I would never have to worry about running out of alternator.

aidandj

iTrader: (5)

<p></p><p>Link to details?</p>

patsmx5

iTrader: (16)

I didn't post a writeup/separate thread on it but it's in my build thread here: [NB] Pats W100AX Whipple Twin Screw Build - MX-5 Miata Forum

If you have any specific questions feel free to ask and I'll answer them though.

EDIT:

Doppelgänger

iTrader: (12)

******* ****, had a long reply typed up and got some log-in SNAFU crap. Oh well.

Anyway. I think I found my answer by being patient enough to re-read the FM Hydra instructions. It looks like there can be an issue of the batt. voltage reading being a bit lower than actual system voltage, that oscillation in the system is a sign of a dying alternator, and that I'm not completely nuts to have initially thought that my radio cutting out could be spikes...even though I didn't "see" it while monitoring data. I'll be ready to get some data and see what batt. voltage readings I see when the radio cuts out, perhaps it'll give me an idea of how much of a difference there is between what Hydra shows when there is enough to cut the radio out/what's really in the system. I have not noticed other lights on the dash coming on when the radio has cut out, but I'll keep an eye out. But yeah, definitely will be trying to get my hands on a alternator ASAP.

**As I typed that up, I got an email from Jeremy @ FM telling me that my old map won't be too happy with the new firmware upgrade I just made....probably explaining the idle issue that popped up lol. Go figure.

On that last bolded part below- I wonder if my AFR dithering could be a result of these potential voltage spikes and/if it's toast because of this.

So while I may have found my answer, I've learned a few things here for sure...and maybe someone else having such an issue will find this thread helpful.

codrus

IMHO, the best way to debug this kind of stuff is to get a $10 battery voltage gauge, wire it into the car in a good location, and mount it somewhere you can see it while driving. As you've seen, the Hydra's voltmeter can be offset from the voltage elsewhere in the car by a significant amount (and not always a consistent amount, either)

One way that alternators die is to drop output at high RPMs due to wear on the slip rings. At 60K miles, my original alternator would output 65A at 2000 RPM, but only 30A at 6000. Doing acceleration runs at night would result in visible headlight dimming as the RPMs rose.

--Ian

Doppelgänger

iTrader: (12)

Interesting.

I'm going to make some tweaks to the map Jeremy just sent me and see what happens.