Alternator Problems

[Spanky_DSM]

Someone please help me get my car running before sundown. the cars alternator is good but it passes no charge at all to the battery! Anyone please help with the possible flaws causing it to fail. fuses, relays, wiring. where each fuse is located please. Thank you so much.

 

[FIBA M - EC17PSE]

Have you checked that the battery is good aswell and not completely dead as it won't even hold a charge if its dead! (Check it all with a multimeter)

Check the power wire for cracks, its not the greatest task to do but its something that needs to be done to make sure!

Also lift the fuse box cover in the engine bay and look at the top left big fuse 100amp mines blue yours might be another color but that's linked to the system and if blows can cause it to not charge! Normally this blows if you jump start it wrong or the alternator spikes! That's the fuse that made mine not charge aswell

 

[Spanky_DSM]

Have you checked that the battery is good aswell and not completely dead as it won't even hold a charge if its dead! (Check it all with a multimeter)
Check the power wire for cracks, its not the greatest task to do but its something that needs to be done to make sure! Also lift the fuse box cover in the engine bay and look at the top left big fuse 100amp mines blue yours might be another color but that's linked to the system and if blows can cause it to not charge! Normally this blows if you jump start it wrong or the alternator spikes! That's the fuse that made mine not charge aswell

i did check the 100 choke fusible link by eye but ima bust out the multimeter today and go check it out right now. any1 know what readings im suppose to get from the wire harness of the alternator. also the ground cables i think which are covered by the orange cap.

 

[FIBA M - EC17PSE]

The orange cap on the alternator wire is positive! If that's what your on about?? The ground is on the underside of the alt and you need to do that from under the car!

Readings are around 13-14 from the alt are fine mine reads anywhere from 13.5-14.6, check the battery and see if its seeing any charge atall! then work backwards, there is a relay under the intake box near the boost contoller thing but I'm not really sure if that's a cause but as I cannot remember what I read about it I won't say anything on that ha ha don't want to say some wrong info now ;-)

 

[Spanky_DSM]

The orange cap on the alternator wire is positive! If that's what your on about?? The ground is on the underside of the alt and you need to do that from under the car!

Readings are around 13-14 from the alt are fine mine reads anywhere from 13.5-14.6, check the battery and see if its seeing any charge atall! then work backwards, there is a relay under the intake box near the boost contoller thing but I'm not really sure if that's a cause but as I cannot remember what I read about it I won't say anything on that ha ha don't want to say some wrong info now ;-)

yea i came across that info about the alternator relay that people claim is no alternator relay but some1 fixed their alternator replacing it

well then if those 2 cables on the orange cap are positive then where is the ground?? i dont recall anyother wires besides the plug harness. and thanks for the replys. Its almost sundown. need my car for tonight

 

[miguelmcv]

Check your Alternator with the Voltmeter.

Test the wire at the alternator and check the same wire at the Fuse Box, It should be the same, If It is not the same, then your Wire is fried, Check the Fuse. Some times it looks good but when pulling out it is not good.

You have to see the same Volts at all the places. (alternator, fuse box and battery).
It should read over 13v. If there is under 13v. (your alternator is not good).

Do that Test and report the Results.

 

[Spanky_DSM]

Check your Alternator with the Voltmeter.

Test the wire at the alternator and check the same wire at the Fuse Box, It should be the same, If It is not the same, then your Wire is fried, Check the Fuse. Some times it looks good but when pulling out it is not good.

You have to see the same Volts at all the places. (alternator, fuse box and battery).
It should read over 13v. If there is under 13v. (your alternator is not good).

Do that Test and report the Results.

battery and alternator readings were 12.25 while running and bouncing up and down.

alternator is rebuilt and after installing it i took it off and took it to him and he opened it up and tested it and he said it was good. im guessing a bad connection somewhere or a fuse?

 

[faudin]

check for voltage drops across alternator grd and insulated circuits.

With vehicle running turn on all electrical loads; put voltmeter put red lead on alternator output terminal and black lead on positive battery post.

test ground circuit by putting red lead on alt case and black lead on battery neg post.

should read not more than .1 volts per connection or more than 0.3v total. If detect voltage drop higher than this you have bad connection or high resistance in the circuit.

 

[Spanky_DSM]

check for voltage drops across alternator grd and insulated circuits.

With vehicle running turn on all electrical loads; put voltmeter put red lead on alternator output terminal and black lead on positive battery post.

test ground circuit by putting red lead on alt case and black lead on battery neg post.

should read not more than .1 volts per connection or more than 0.3v total. If detect voltage drop higher than this you have bad connection or high resistance in the circuit.

ima go out and try that right now . thanks

 

[faudin]

kk let me know how you make out

 

[Spanky_DSM]

kk let me know how you make out

on what setting should the multimeter be set to. sorry im new to this. and what should be the readings for the red clip on alternator output and black on positive battery post. dont think you measured the readings for those.

 

[FIBA M - EC17PSE]

You have to see the same Volts at all the places. (alternator, fuse box and battery).
It should read over 13v. If there is under 13v. (your alternator is not good).

Do that Test and report the Results.

That's not true it don't have to be over 13v for it to charge!! As mine sometimes reads 12.5 and it still charging. As long as its over 12 then its fine there have been many people with this number and still driving there car today with out over loading anything! Mines fine and has been like this since my new OEM alternator was put on! It will fluxuate anyway when lights and A/C is on etc etc!

And as to your question on the neg part you have 3 things that hook up to the alt! The plug with 4 wires that send signal to the ecu and the battery light inside thae car and other things that I cannot remember at this time (sorry). Then the orange cap which is positive! And under the alt is another wire and that's the negative! You can't see this unless you go UNDER the car!

 

[faudin]

I am not going to sit and argue with anyone on a forum because it is just worth it, but here is how your charging system works

The charging output of the alternator is controlled by a voltage regulator which may be mounted inside or on the back of the alternator (internally regulated), or somewhere else under the hood (externally regulated). On most newer vehicles, the powertrain control module (PCM) regulates charging output.

On older vehicles, the voltage regulator was electro-mechanical and used magnetic contacts to control the charging output of the alternator. Since the 1980s, most voltage regulators are solid-state electronic and use transistors to control charging output.

The actual output voltage produced by the alternator will vary depending on temperature and load, but will typically be about 1-1/2 to 2 volts higher than battery voltage. At idle, most charging systems will produce 13.8 to 15.3 volts with no lights or accessories on. This can be measured by connecting the positive (+) and negative (-) test leads of a voltmeter to the battery posts while the engine is running.

Most alternators that are charging properly should produce a voltage of about 13.8 to 14.2 volts at idle with the lights and accessories off. Always refer to the vehicle manufacturer's specifications for example.

When the engine is first started, the charging voltage should rise quickly to about two volts above base battery voltage, then taper off, leveling out at the specified voltage.

The exact charging voltage will vary according to the battery's state of charge, the load on the vehicle's electrical system, and temperature. The lower the temperature the higher the charging voltage, and the higher the temperature the lower the charging voltage. The "normal" charging voltage on a typical application might be 13.9 to 15.1 volts at 77 degrees F. But at 20 degrees F. below zero, the charging voltage might be 14.9 to 15.8 volts. On a hot engine on a hot day, the normal charging voltage might drop to 13.5 to 14.3 volts.

Do a voltage drop test with the engine idling, touch one test lead of your voltmeter to the battery positive (+) post, and the other test lead to the BAT (B+) terminal on the alternator. Ideally, the voltmeter should read less than 0.2 volts.

If you see a voltage reading greater than 0.2 volts, it means there is excessive resistance somewhere in the circuit causing a voltage drop in the wiring circuit. Check all the wiring connections (use electronics cleaner to clean connections), and make sure the terminal connectors on the ends of the wires are clean and tight.

A negative side ground circuit test is made by touching one voltmeter test lead to the alternator housing, and the other test lead to the negative battery post (not the terminal clamp) with the engine running and charging system loaded. If good, the voltage drop should be 0.2 volts or less. If higher, inspect and clean all ground connections as needed. Also, check for broken, loose or missing ground straps between the engine and body.

If the alternator output circuit and ground circuits test good (voltage drop less than 0.2 volts) and the vehicle has a history of repeated alternator failures due to burned out diodes, check for a shorted indicator light terminal.

Checking for voltage drops in a circuit is a good way to find hidden problems that may be causing a charging problem. Voltage drop tests must be done while the engine is idling with a charging load on the system. In other words, there must be voltage flowing through the circuit for the voltage drop test to detect a problem. Voltage always follows the path of least resistance, so if the connection being tested has too much resistance some of the voltage will flow through the voltmeter and create a small voltage reading.

Voltage drops on the positive side can cause undercharging.

Voltage drops on the negative side can cause overcharging (fools the voltage regulator into thinking the battery is low)

 

[Spanky_DSM]

And under the alt is another wire and that's the negative! You can't see this unless you go UNDER the car!

i thought the alt didnt have a negative cable? i thought it was grounded just by being bolted on?

 

[miguelmcv]

That's not true it don't have to be over 13v for it to charge!! As mine sometimes reads 12.5 and it still charging. As long as its over 12 then its fine there have been many people with this number and still driving there car today with out over loading anything! Mines fine and has been like this since my new OEM alternator was put on! It will fluxuate anyway when lights and A/C is on etc etc!

And as to your question on the neg part you have 3 things that hook up to the alt! The plug with 4 wires that send signal to the ecu and the battery light inside thae car and other things that I cannot remember at this time (sorry). Then the orange cap which is positive! And under the alt is another wire and that's the negative! You can't see this unless you go UNDER the car!

Not because your battery doesn't die it means that your alternator is charging good.

Our alternators are tricky, They go up and down and when it happens, it means they are not working good.

I have change 4 alternators in 1 Month, and some of them were checked and tested working good.
After having a big discussion they end up giving me another Alternator, which it was good.

About the the ground under the alternator.

There is no such wire underneath the alternator.

The alternator gets grounded by being bolt it on.

 

[shay4g63]

i have the same problem on my 1992 .. according to my safc2.. my voltage(and i can see it with healights) goes from 14.8-13.4-12.1-11.6 then back up to 14.8 and will hang out there for a couple hours.. then back down but after driving for a hour it mainly hangs around 13.2-13.8.

i've checked everything. gonna throw another alt in. I'm wondering with the upgraded turbo systems if our alts. get to hot? I just heat wrapped my stuff and with my hy-35 soon i'll be having to watch temps more.. because he gets HOT under my hood. but the engine temp is cooler then my buddys stock talon.

 

[Spanky_DSM]

i have the same problem on my 1992 .. according to my safc2.. my voltage(and i can see it with healights) goes from 14.8-13.4-12.1-11.6 then back up to 14.8 and will hang out there for a couple hours.. then back down but after driving for a hour it mainly hangs around 13.2-13.8.

i've checked everything. gonna throw another alt in. I'm wondering with the upgraded turbo systems if our alts. get to hot? I just heat wrapped my stuff and with my hy-35 soon i'll be having to watch temps more.. because he gets HOT under my hood. but the engine temp is cooler then my buddys stock talon.

dang yeah that use to happen to it to my car. at cold start voltage would go down but after warm up it will stay up. took it off and had it checked which everything came by good. now it wont even maintain a good charge

 

[FIBA M - EC17PSE]

Not because your battery doesn't die it means that your alternator is charging good.

Our alternators are tricky, They go up and down and when it happens, it means they are not working good.

I have change 4 alternators in 1 Month, and some of them were checked and tested working good.
After having a big discussion they end up giving me another Alternator, which it was good.

About the ground under the alternator.

There is no such wire underneath the alternator.

The alternator gets grounded by being bolt it on.

I went with the oem alt and its sits around 12.5+ and its fine! Not had any problems.

And I'm not sure why but I have 2 wires on mine then! A neg and a pos and the 4 wire plug? Wonder why mine has this and yours don't! Maybe that's what's messing your alternators up but I 100% have 2 wires for the alt and there all standard in cased in the factory protective sleeve

 

[97gst_spyder]

The ground is not hooked up from the factory. Someone may have added it, but I have never seen any DSM with that wire factory.

It will not hurt to add that ground to the chassis, but most likely won't fix your problems.

When was the battery replaced? Whats the amp rating on it? When they tested your alt, what was the voltage coming off it? If you leave your map light/door open for an hour does your car barely start?

 

[FIBA M - EC17PSE]

The ground is not hooked up from the factory. Someone may have added it, but I have never seen any DSM with that wire factory.

It will not hurt to add that ground to the chassis, but most likely won't fix your problems.

When was the battery replaced? Whats the amp rating on it? When they tested your alt, what was the voltage coming off it? If you leave your map light/door open for an hour does your car barely start?

100% don't look like someone has added this! Looked at it again and it looks like a bracket to hold up the other wires but its also got another wire moulded into the bracket and as I said looks standard! Battery was replaced before winter with the exact amps and whatever else like the stock battery!

My alt was generating 12.8-13.7. And is still around that today and is fine!

I left my door open while doing some wiring last month for about 1.5 hours and it started straight up!

I've got to re do my FOG light wiring next week so I'll test the battery before and leave the door open and once I've rewired it I'll re test the battery to see what drain is on the bettery aswell!

Any way its not about me haha its about the OP so sorry to jack it! My cars just special

 

[Spanky_DSM]

well i used a new battery to start the car and the readings were at 12.3. if i turn on my lights it starts to go down slowly :?

i found this to be a bit odd. Please follow the link and post anything that might be helpful. Thanks you

http://www.dsmtuners.com/forums/newbie-forum/409869-plug-question.html

 

[97gst_spyder]

Honestly if the alt is producing less than 13v at idle its not ok. It may be a shot positive wire (2 white ones) or a ground. I've also seen a loose belt cause this low voltage issue also.

Between my 2 spyders I've damn near seen ever electrical issue out there. From simple no fuel, to the left blinker indicator stays on, to my headlights came on with the key in the passenger side door... Seriously.

Also, the lower the voltage is to 12 the more issues you will have ( mis fires, idle issues, sensor readings off, etc.).

Once I installed my saturn alt(105 amp) and re wired the engine positives with 4 ga, grounds with 4ga wire also. I have 14.5-14.7 volts all the time. A/c, lights, radio, etc.

 

[Spanky_DSM]

Honestly if the alt is producing less than 13v at idle its not ok. It may be a shot positive wire (2 white ones) or a ground. I've also seen a loose belt cause this low voltage issue also.

Between my 2 spyders I've damn near seen ever electrical issue out there. From simple no fuel, to the left blinker indicator stays on, to my headlights came on with the key in the passenger side door... Seriously.

Also, the lower the voltage is to 12 the more issues you will have ( mis fires, idle issues, sensor readings off, etc.).

Once I installed my saturn alt(105 amp) and re wired the engine positives with 4 ga, grounds with 4ga wire also. I have 14.5-14.7 volts all the time. A/c, lights, radio, etc.

yea my car does misfire and lights flicker. hmm ima do some more inspecting right now and ill let you guys know what i found

 

[97gst_spyder]

100% don't look like someone has added this! Looked at it again and it looks like a bracket to hold up the other wires but its also got another wire moulded into the bracket and as I said looks standard! Battery was replaced before winter with the exact amps and whatever else like the stock battery!

My alt was generating 12.8-13.7. And is still around that today and is fine!

I left my door open while doing some wiring last month for about 1.5 hours and it started straight up!

I've got to re do my FOG light wiring next week so I'll test the battery before and leave the door open and once I've rewired it I'll re test the battery to see what drain is on the bettery aswell!

Any way its not about me haha its about the OP so sorry to jack it! My cars just special

Now I know what your talking about. The bracket like part. I never thought of it as a factory ground.

 

[Spanky_DSM]

Now I know what your talking about. The bracket like part. I never thought of it as a factory ground.

i have the bracket that bolts onto the alternator aswell that holds the wires but i see no wire connected to the bracket. i did find a yellow wire that comes from the same wiring as the alternators cables but other people said it was for my oil pressure. the skin of the wire is yellow covers with a gray straw, same as the alternator wires. could that be the ground?