Mechman Alt Problem!!! Help

[BoomBoxB 0]

Well it took me forever but i got my 250 amp Mechman alt in this weekend, had to get a different size belt to run it... well problem is my car is sitting at 11 - 11.3 volts!!!! even with the stock alt it would hit 14... i dropped a pretty penny on this, and its way worse than my stock. i have had the big 3 on for 6 months.

is this bad for my car?

i have a long road trip coming up ion a couple weeks and this needs to be fixed.

whats my problem????

Edited March 23, 2009 by BoomBoxB

[bobonit 5]

Well it took me forever but i got my 250 amp Mechman alt in this weekend, had to get a different size belt to run it... well problem is my car is sitting at 11 - 11.3 volts!!!! even with the stock alt it would hit 14... i dropped a pretty penny on this, and its way worse than my stock. i have had the big 3 on for 6 months.

is this bad for my car?

i have a long road trip coming up ion a couple weeks and this needs to be fixed.

whats my problem????

First and easiest thing to check would be how tight is your belt? If you push against it with your finger, how far can you move it? It could be slipping. Ribbed serpentine belts are very quiet when slipping.

[ford302redneck 15]

Also, make sure all the wires are connected. Hell the factory harness could have broke.

If its not charging at all, means something is wrong totally. Not just a shitty alt, theres a slim chance it could be a defect alt. Email Mech and see what they have to say first.

[BoomBoxB 0]

all connections are tight, and belt is very tight. im going to call but they are not open yet.

thanks

[BKOLFO4 29]

Sounds like it is just running on battery voltage.

Check the ignition exciter wire and make sure it is 12 volts with the key on. Maybe you blew the fuse. . .

[BoomBoxB 0]

Sounds like it is just running on battery voltage.

Check the ignition exciter wire and make sure it is 12 volts with the key on. Maybe you blew the fuse. . .

i don't understand

[BKOLFO4 29]

from the quick pics I found, it should have an additional connection other than just the battery charge wire. If this connection is not pluged in, or does not have power running to it, the alternator will not "start up".

[BoomBoxB 0]

i just checked it is plugged in, im pretty sure the alt is working because if i listen to music it can drop to 10 volts then back up to 11, so im not listening to my subs i dont wanna screw up the amp.

[BoomBoxB 0]

finnaly got a hold of the man himself, and he gave me some tips on checking everything i will be doing this when i get home, im sure thats the problem. at least i hope so i wanna hear my subs at 14volts!!!!

he thinks that the alt is not turning on at all.

Edited March 23, 2009 by BoomBoxB

[BKOLFO4 29]

that is what I said above. I bet you can measure the voltage with the car running or off and will see the same reading.

Just curious, what did he say to check?

[BoomBoxB 0]

he told me to check if yellow wire is getting constant 12 volts, green wire is getting keyed 12volts.

if not i have a blown fuse somewhere.

[Noobtastic14 0]

when you did your big 3- did you upgrade your wire from alt positive to bat positive?

if you missed/forgot this wire that H/O alt will pop your stock alt fuse VERY quickly!!! get a DMM and check those wire and get back to us

-Drew

[BoomBoxB 0]

yeah my alt to + battery is there. 1/0

and on this alt there is also a ground that i hooked up to the - on the battery.

Edited March 23, 2009 by BoomBoxB

[shizzzon 461]

You ran the ground from the alt directly to the battery?

I've never heard of anybody doin this... wonder if that's wise?

You also said that you would rest at 11v but your voltage would drop to 10v then back to 11v when music was turned down or off...

Just a tip for future reference-

Take a fresh battery, 12.6v batt and hook it up through a cranking simulator at auto zone.

It will pull it's rated CA so let's say it's 600A. When this happens, the batt will drop from 12.6 to 10.5v then will immediately recover to 12.2v... then 12.3, then 12.4, then 12.5 then 12.6v

You see, battery can still be 12.6v and not be fully charged. Likewise, batteries "recover" once they are discharged and depending on how good they have been taken care of is dependent on how good they recover!

Your battery sitting at 11.0 or 11.x is not good! the battery can sustain major premature failure if it sits in a state like this for months. The batt needs to be fully charged immediately and checked again a few hrs later to ensure that the float voltage does not drop below it's normal value.

[BKOLFO4 29]

You ran the ground from the alt directly to the battery?

I've never heard of anybody doin this... wonder if that's wise?

It is actually the best way. . .path of least resistance will be a nice piece of 1/0 wire vs. through brackets, engine, ground strap, frame, etc.

Mechman puts ground studs on their alts just for this.

[shizzzon 461]

just curious. I know most engine bays i've seen, the alt is pretty far away from the battery, total opposite side. But i was also curious even if it was just a foot away.

Okie dokie then.

[BKOLFO4 29]

Even at 6 ft long, the resistance in decent 1/0 is way less than the path through the bracket, engine, frame path.

Connection points are more resistance than the wire itself.

[BoomBoxB 0]

i was running on the battery.

ok seems the problem was my factory harness going to the alt had some kind of corrosion on it somewhere and was only getting 6 volts. so what i did was cut the power wire out of the Mechman alt harness and put a ring terminal on it and stick it on the + end of the alt. this way the car was telling the alt to turn on straight from the battery.

now i'm sitting at about 14.5 volts so needless to say im pretty happy. just took a couple days.

thanks for the help.