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-   -   Odd electrical issue ? Fan related ? Dunno ? (https://www.miataturbo.net/general-miata-chat-9/odd-electrical-issue-fan-related-dunno-25314/)

mtncrvr 08-25-2008 09:08 PM

Odd electrical issue ? Fan related ? Dunno ?
 
Long post but plz read - this is just weird:

So I just switched to the 2x12" ~1500cfm siliconintakes fans and used factory wiring since they claim to draw only 6amps and the factory fan circuit is 30 or 40 (don't recall but it's far beyond what these fans draw). Also noteworthy is I've had weird alternator problems in the car over the last four years (I've replaced the alternator 3x now) but the current one seems to be fine and I run an optima red top so lots of reserve power.

My radar is hard wired in and serves as a voltage meter and alert for high or low voltage (it's a pretty decent Bell unit). I just added a lexan undertray (I love it - hwy temps down 20 deg!!!) and removed my passenger fog light and stuck my oil cooler in this spot and I see 15 deg lower oil temps :-) this weekend.

Now on to the weirdness. I was driving home in annoying 45-50 mph traffic (on a hwy thats 65mph) with some stop and go ~84deg out with high humidity and I ran A/C which is still causing overheating or rather just running hot (215 or so with A/C on, 178 with A/C off) no more bubbling over the resivoir with the new 60% coolant/40% distilled water mix and a 16psi cap - thx to member tips (I love this site).

All of a sudden my radar goes apeshit warning of overvoltage for a good 15 seconds ??? I thought it was just freaking out from being in the hot car all day and power cycled it but it came back on with the same warning of over voltage ?? My radio / gauges, ECU etc all seemed fine (no excessive brightness or odd behavior), wipers worked (it was raining slighly). So I turned off the A/C and the warning stopped shortly after (like a few seconds) ? I smell a burning smell and think great blown fuses maybe caused by something rubbing and shorting (I'm annoyingly vigilant about over insulating hoses and wires where they have potential to rub).. I turn the A/C back on and it's fine, nice cold air - so now I'm thinking maybe I lost a fan and only the A/C fan is running (even though i have dual fan mod since the fans are new - maybeone is bad?). I get to the local ABC store (this is where you gotta go to get booze in NC) and pop the hood and everything looks normal - both fans operating normally, I check and all the fuses look fine except the EGI MAIN (the 80AMP in the engine bay) is really hot and no visual way to tell if it's blown except the car prob wound't run at all if it was - this fuse is bolted into the engine bay fuse box - but who knows it may just run hot anyway - I've never really checked it b4. The one thing I do notice is my headlamps are both out - so I check all the fuses for them and they're all good ? Check voltage at the plug for the bulb and there's power so I take a spare bulb and plug it in and I have light ?? WTF - I just fried an 80$ pair of PIAA's :-( What could casue an overvoltage that lasted that long (15seconds) ??? Certainly the fans if they freaked would cause undervoltage at worse and/or would have just blown the fan fuse ? Did the built in voltage reg on the 8 month old bosche alternator wig for just the 15 seconds ?? And no I don't under or over drive the pullies - all stock there. Thoughts ? I don't wanna see the same thing fry something more expensive like a wideban or my xede or ecu ?

Thoughts / speculation welcome :-) One thing to note - I have had to replace the plug on the driver side headlight since it melted but now the cold air intake is keeping it cool. Dunno why it melted - that was with factory bulbs...

TIA,
-B

patsmx5 08-25-2008 09:47 PM

Make sure your battery connections are clean and tight. Loose connection can cause exactly what you just described. The battery runs the car. The alternator charges the battery. (I don't care what anyone says that's my belief and I don't wanna hear otherwise)

mtncrvr 08-25-2008 10:03 PM


Originally Posted by patsmx5 (Post 300957)
Make sure your battery connections are clean and tight. Loose connection can cause exactly what you just described. The battery runs the car. The alternator charges the battery. (I don't care what anyone says that's my belief and I don't wanna hear otherwise)

Will check the connections - I had a quick disconnect added when the optima battery was put in - though the soft top needs replacing and the top drains need cleaning so its possible the ground is coroded a bit - will check and clean (along with some condutive grease :-)



Thx,

-B


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