s4 winter starting problems...

[gerudas11]

Here is the situation. I have had my 7 for about 2 n a half years. I never been able to drive it in the winter because it doesn't want to start. battery gets too low, sometimes I have to use "cheater" fluid to get it to fire up if the battery has enough juice. I'm thinking that my alternator is going bad or I need to go through and re-ground some wires. couple questions... is there a better alternator than a rebuild s4 that isn't going to cost me an arm and leg? Does some of the big ford alternators work like they work for the rx8s? Does it sound like the motor needs to be rebuilt? motor has about 120xxx during the warmer days it drives fine other than I need some back pressure because of the after market exhaust that was put on. I would rather not rebuild it because I have a gto that I would rather spend the money on plus if it needs rebuilt then I will probably build up the 327 block that is sitting in my garage. any help would be great.

Thanks,

Jarrad Grider

[gerudas11]

I also have another alt. that I may try to use to see if I get a better voltage.

[My5ABaby]

You can switch in an S5 or S6 alternator with a quick wiring job (very very simple). I believe the amperage is S4=70, S5=80, S6=100.

[gerudas11]

Now is there anyway an rx8 one will work? I know that a certain ford alt works with the rx8 because my buddy was telling me that... if not I'll look around for an s6 next week because I want to drive my 7 so much... love/hate relationship.

[NoDOHC]

Ok, please correct me if I am mistaken, but you are talking about a starting issue here.

The alternator only produces current to charge the battery after the engine has started.

You could put the greatest alternator known to man on that car and it wouldn't help your starting at all.

What you need for good winter starting:
A GOOD battery.
Low contact resistance on every connection between your starter and your battery.
Low viscosity motor oil (don't go less than 5-30).

I drove my '86 several winters back when it was stock and it started just fine with many more than 120,000 miles (like 160,000 one winter and 180,000 the next).

I could walk outside right now and start it and it is 3 degrees F right now (of course it has an aftermarket ECU and a rebuilt engine now too).

Here is what I had to do to get it to start on a really cold day (below 0F):
Hop in Car, push clutch down enough to disengage, but not too far (added resistance from throwout bearing).
Crank car until it fired, then give 25% throttle instantly.
Car would sputter a little, then rev to 3,000 rpm.
I could then gently release the gas, keeping the revs at 3,000 rpm.

I was using:
725 CCA battery
5W-30 Motor oil
Stock ECU with 12 degree advanced timing.

Now I have:
550 CCA battery (behind the passengers seat)
15W-50 Motor oil
Haltech ECU

The car starts much better with the Haltech than it ever did stock. I don't think that Mazda calibrated the stock ECU to start at very cold temperatures, it is not a mechanical problem, it is a calibration issue.

[gerudas11]

Yeah I am basically talking about a starting issue. The battery is 700cca. 875 @ 32degrees. The battery is not even two years old and I have to get it recharged every couple months bc I believe the alternator doesn't keep it charged. Also my voltage drops when I roll my windows up or down. Turn on the radio, heat ect. Ill change the oil tomorrow try the other alt that I have and put the battery in as well.

[gerudas11]

So after I got off of work today, I went to go check on my batt. Dead battery they gave me a new one because it was only 1 yr and 6 months old. changed the alternator as well because the re-manufactured one was low voltage. inside it looks like the car is now reading right under 14. I'm hoping it will fire up tomorrow but the low tonight is 29 so its not that cold, yet. I am still going to look for an s6 unless the rx8 alternator can work on the s4.

Another question

Should I change the wiring for the battery, starter, and fuse box? I saw somewhere that a guy was going to run 4ga from the battery to the starter and 8ga to the fuse box... is this a good idea? I'm pretty good with wiring so that will be an easy job.

Thanks,

Jarrad Grider

[FlybyRE]

No need to change the wiring.. just make sure all your grounds are clean.. Pull the ground wires up.. sand down the contact surface and bolt them back down..

Deff sounded like a battery issue... I would have suggested an Optima Yellow Top.

[gerudas11]

update
So it looks like it was the old re manufactured alternator and battery was the problem. Car has fired up everyday I have drove it the past 4 days with no problems its been raining, snowing, and under 25 degrees with no problems. I still want to upgrade the alt next weekend hopefully.

[NoDOHC]

Awesome! Thanks for keeping us posted.

You had it pegged right from the start, I thought you meant that the battery was going dead while cranking, not while driving.

Good job.