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rx4ur7 · 08-11-2009, 12:52 PM

DO NOT PUT A LARGER FUSE IN! You will just overload the wiring. Check for bad grounds, voltage drop in any wiring, clean battery term ends.
I would caution everyone on jump starting any vehicle built after 1990. Or any car that is reliant on electronic controls.
Incorrect jump starting has been the cause of many ecu failures to either vehicle due to high voltage or amp surging, especially if the jumped car has a dead battery.
Safest of course is to remove battery and charge it.
If the battery is just low, the safest is to hook up the cables and have the jumper run for a while. Shut the jumper car off then start the jumped car.
It only takes a milliamp to blow circuits in ecu's.
Jump starting is the main cause of ignitor failure in the first gen 7's. I have a box full of dead ignitors that are proof.
I will continue with my mantra, check all grounds, check for high resistance and voltage drop. Get a book on basic electrical testing procedures.
Get a Mazda altenator, I have never had any luck with rebuilds. In all the Mazda altenators and starters I have replaced in 30+year I have had two, one of each that were bad and they failed in the first week of use.
Yes aftermarkets have great warrenties, if you like replacing them every 6 months.
Personally I do not want to see a vehicle again for the same issue.
Usually the only times I see odd ball failures is from someone thinking they can out engineer the factory or have rewired the car and missed something.
The other times, bad grounds.
If you have a good battery 12.5 to 14.7 at idle with no load is normal. (12.5 for fully charged)
Mazda specs
B term key on Va (battery) 14.1-14.7 idle
L term ~1 12.9- 13.5
S term Va 14.1 - 14.7
One other thing-
Check for draw, easiet way, disconnect ground cable and put a test light, not a DVM, between cable and battery, if it lights you have a draw.
Pull fuses until you find the circuit. I it still stays on disconnect alt. On a vehicle that has not been tampered with you should find the problem. If not, you are in for a long slog of aggrevation, good luck.
On new cars there is always some sort of draw, but it should not be enough to power a light bulb.
Hope this is of some help.

08-11-2009, 12:52 PM	#24
rx4ur7 Rotary since 1972 Join Date: Nov 2008 Location: Tucson Posts: 231 Rep Power: 17	DO NOT PUT A LARGER FUSE IN! You will just overload the wiring. Check for bad grounds, voltage drop in any wiring, clean battery term ends. I would caution everyone on jump starting any vehicle built after 1990. Or any car that is reliant on electronic controls. Incorrect jump starting has been the cause of many ecu failures to either vehicle due to high voltage or amp surging, especially if the jumped car has a dead battery. Safest of course is to remove battery and charge it. If the battery is just low, the safest is to hook up the cables and have the jumper run for a while. Shut the jumper car off then start the jumped car. It only takes a milliamp to blow circuits in ecu's. Jump starting is the main cause of ignitor failure in the first gen 7's. I have a box full of dead ignitors that are proof. I will continue with my mantra, check all grounds, check for high resistance and voltage drop. Get a book on basic electrical testing procedures. Get a Mazda altenator, I have never had any luck with rebuilds. In all the Mazda altenators and starters I have replaced in 30+year I have had two, one of each that were bad and they failed in the first week of use. Yes aftermarkets have great warrenties, if you like replacing them every 6 months. Personally I do not want to see a vehicle again for the same issue. Usually the only times I see odd ball failures is from someone thinking they can out engineer the factory or have rewired the car and missed something. The other times, bad grounds. If you have a good battery 12.5 to 14.7 at idle with no load is normal. (12.5 for fully charged) Mazda specs B term key on Va (battery) 14.1-14.7 idle L term ~1 12.9- 13.5 S term Va 14.1 - 14.7 One other thing- Check for draw, easiet way, disconnect ground cable and put a test light, not a DVM, between cable and battery, if it lights you have a draw. Pull fuses until you find the circuit. I it still stays on disconnect alt. On a vehicle that has not been tampered with you should find the problem. If not, you are in for a long slog of aggrevation, good luck. On new cars there is always some sort of draw, but it should not be enough to power a light bulb. Hope this is of some help.