BuckyB34

Heyo! Ive got a 1993 turbo miata with a 1.6L turbo longnose and I need help!
I was driving home and out of no where the battery light came on and my AFR gauge started reading 7.4... car was hitting a limiter of sorts at around 4200 RPMS or so... then my RPM guage stopped working and lights began to dim. ANY IDEAS?? I know it needs a tune and has a power draw from somewhere.... any ideas my lovely hairdresser friends?
Thanks!! <3

Braineack

iTrader: (62)

fix your battery/alternator.

car wont work if the voltage is pegging past 14v or dropping below 10v.

borka

iTrader: (1)

your alternator died. go replace it.

ChrisLol

Low battery voltage will cause the ECU to increase injector opening time/dead time. Perhaps this is not setup correctly in the ECU and adds way more injection time than necessary at low battery voltage resulting in a rich condition.

Low voltage to the ignition coils means that the coils need longer dwell times to charge fully. If this is not compensated for then the spark simply wasn't strong enough at that RPM to ignite all of the fuel and continue accelerating the engine.

What they said, the alternator is likely DED and all problems above stem from that.

BuckyB34

Thank you! I know it has a yellow top optima battery. It could be sprung from that battery. The guy said he replaced the alternator thinking that was the source of the power draw but it didnt solve the power draw issue. If I put a miata battery in it, do you think that would be worth my time checking or should I just replace the alternator before wasting my time on that?
Thanks for the response!
-Bucky

Braineack

iTrader: (62)

explain "power draw"

I'm assuming in this case the definition is: I have no clue how to wire things, but did it anyway, now the car runs like **** so I guess ill sell it.

BuckyB34

Basically yeah. Unless you unplug the battery, the battery drains. I'm assuming its some ground or maybe the dude doesnt know how to wire gauges and sold it out of frustration.

ChrisLol

Google "Parasitic Draw Test" It's relatively easy test to do with a multi-meter.

Also, Vatozone/Advance Auto have alternator diagnostic carts they can check the output of the alternator with an amp-clamp if you can get it there.

Braineack

iTrader: (62)

find everything non-oe and unplug it. he probably wired the wbo2 to the constant battery voltage wire on 1A or something.

I had a relay that would stick once. I had to pull it every time I shut off the car or the battery would drain. cant remember how I figured it out... I think it was when I was adding a/c input to my MS and I did something stupid with the wiring.