alternator/voltage regulator

cbarr300 · Apr 1, 2007

Hey guys.....

I recently got a new alternator from pepboys and installed it.

Now, whenever I crank the car I have around 13.7 volts it idle....then if I touch the gas at all the alternator will just stop working and I will be running off of battery power.

I used the "ground here to test" screw on the back of the voltage regulator and nothing happened voltage wise. I'm just wondering if there's anything else it could be other than a faulty regulator/alternator.

btw, the harness is good. I still need to check if I'm getting 12V into the alternator though.

Thanks

HISSIN50 · Apr 1, 2007

Clay, there are 3 Reg terminals - A, S, I.

A should be battery voltage. True voltage. If it's dropped more than about 100 mA, that can lead to issues (though not your issue).

I is 12 volts from the ignition switch. As long as you have more than about 10 volts (and your battery light is not illuminated), you should be fine.

S is the stator circuit.

If your alt has a warranty, I'd not think twice about swapping it in. Even the new parts from parts stores can leave something to be desired (often times, the same mantra about military parachutes holds true for parts-store products).

Good luck.

Car Nut · Apr 1, 2007

Don't feel too bad......

I just bought a new PA Performance alternator and I'm having similar issues. Voltage readings are low and my dash guage and battery light are going nuts, especially over 2000 rpms. I've checked all battery cable and alternator connections and even cleaned the grounds to be sure.

Swapped back my stock alternator and all is good. Just wanted the better PA alternator to replace my refurbished stock one.

If I find out some info from PA Performance on my issue, I'll post it in case it might help. The initial response I got was that I just needed to drive the car for a few hours so the battery would get used to the higher amps going back and forth.

Clean up your ground to the block with some sandpaper, cause that might improve things. Not sure about you, but I upgraded the thicker alternator cable to a 4 guage cable with fuse built in.

cbarr300 · Apr 1, 2007

Thanks guys.

JT: My "I" has power (btw, my battery light DOES come on when I have the car running) but when I checked the "A" it didn't have any positive voltage. Looking at the diagram I noticed there is a fusible link somewhere in the alternator cable and it also looks like the "A" terminal may be connected to it. Could a blown out fuse cause the "A" terminal not to show any voltage and thus not causing any charge....or is that wire not connected to the fuse?

Thanks for the ground tip. I did that last time I was having alternator issues and it definitely helped out.

Oh and also.....I love warranties. I got this alternator about a year ago and it ended up catching on fire (Thank goodness I had a fire extinguisher and had the hood open when I noticed the small flame). I went to pep-boys and bought a new one and completely forgot that the old one had a life-time warranty....so I ended up saving 135 or so.

Bosko5.0 · Apr 2, 2007

the fusable link is right where the cable meets with the fuse block 2 wire into 1 wire

Hissin that seens so familiar.

HISSIN50 · Apr 2, 2007

cbarr300 said:
Thanks guys.

JT: My "I" has power (btw, my battery light DOES come on when I have the car running) but when I checked the "A" it didn't have any positive voltage. Looking at the diagram I noticed there is a fusible link somewhere in the alternator cable and it also looks like the "A" terminal may be connected to it. Could a blown out fuse cause the "A" terminal not to show any voltage and thus not causing any charge....or is that wire not connected to the fuse?

Thanks for the ground tip. I did that last time I was having alternator issues and it definitely helped out.

It still might just be a regulator issue, but I like your idea of seeing if the fusible links are ok. They are in the alt harness as it runs down the driver-side of the PS pump (trace back from the fusebox's power cable connection towards the alternator. Find the end of the wire loom. Then peel back a little bit of loom and they're there - on my car anyhow). I ditched the stock wiring a long time ago but I think that's right.

If the regulator cannot 'sense' battery voltage, it doesn't know what's going on. The sense circuit indeed goes through that underhood fuse as I recall. It's just a way for the regulator to compare battery voltage vs voltage at the alt (like right now, the alt might be capable of putting out 15 volts, but if it's sensing no battery voltage at the PDC, it knows something is wrong).

Also make sure the alternator fuse is ok. It's in the underhood fusebox.

And of course, you can just take the alt in to get bench tested.

If those items look good, I'd be swappin that bad boy in.

I also like the ground upgrade idea. I chose to use a 4 AWG cable and mimic the driver's side secondary ground. My new ground went from the engine side of the passenger side motor mount to the frame rail. This helps assist aging OEM grounds anyhow.

Good luck.

cbarr300 · Apr 2, 2007

wellll......I took the alternator to pep-boys to have it bench tested (sense it's easy and free) and they couldn't get any voltage out of it (I think they just hooked it up wrong). The one I had was a reman'd motorcraft part. They didn't have anymore reman'd units so they ended up giving me a brand new bosch alternator with a gold pulley and everything for the same price.

anywho, I put the alternator on the car and still had the same issue. I'm going to check my fuses once I finish charging my battery up a bit. Is it where the wire splits from one wire to two wires?

thanks for the time :thumbsup:

cbarr300 · Apr 2, 2007

ok...update:

checked my fuses in the distribution block and found a blown 20A fuse....I'm guessing that would be the cause of all my problems soooo......I'm gonna go get another fuse and give it a go. I'm thinking that the reason that it charged when it was at idle was because the little metal connector inside the fuse wasn't completely blown and when I revved it up it had too much power going through it and it'd go out..

If it works out for me, I'll come out of this with a brand new alternator for free.....I'm not complaining.

I'll update later on tonight after I confirm it.

another question...how's the quality on bosch alternators?

cbarr300 · Apr 2, 2007

ok sooo...third post in a row by myself...woohoo

The fuse in the power distribution block ended up being my problem...everything is 100% now.

Thanks guys

Car Nut · Apr 2, 2007

Congrats!

Always nice when you don't have to keep throwing new parts at problems. Good job on scoring the new alternator too.

Electrical issues are never very fun, but it's unreal how much one can learn going through a few problems. My biggest lesson is to clean my grounds a couple times a year (especially since my engine bay gets washed about that often).

cbarr300 · Apr 2, 2007

haha, yeah..the only money I spent was the gas to get there and the 3 bucks for a pack of fuses.

certainly learned a lot too

I'm glad I got the car going though.....a WHOLE lot funner than an accord......

HISSIN50 · Apr 2, 2007

Nicely done Clay. I hadn't replied again because all I knew about the stock fusible links I posted earlier.

Gotta love the cheap fix.

cbarr300 · Apr 2, 2007

oh yeah, cheap=good

I think I'm gonna take your advice and re-do the stock alternator cable...no reason not to.

also, the brand new bosch alternator got rid of some of the squeal in my belt. All the reman'd ones I had, had a slight wobble to the pulley...this one didn't. Now it doesn't squeak anymore....2 birds with one stone.

HISSIN50 · Apr 3, 2007

I just got done swapping an alt on one of the other cars - same deal Clay. It was a reman'd unit and they didnt bother to replace the rear pocket bearing when they took in the core. As a result, it went out in fairly fast order (along with having lost a diode, so I had no output under heavy load - the real issue).

I don't feel bad about spinning and inspecting every alt a parts store has, in hopes of finding the best one. I hate it when they 'yick' - you spin the pulley and hear yick, yick, yick. I also make them load test the brand new alt before I go out the door. I once got 2 bad ones in a row from the same store and wasted a whole afternoon on a 10 minute swap. Lesson learned.

Sorry for the rant.

cbarr300 · Apr 3, 2007

haha, I should have said something when it made that annoying squeaking sound....and the pulley wobbled.

They said that if this one (the bosch one) didn't work...then they'd have to upgrade me to a higher amperage alternator with "all kinds of cool colors" (as the lady said)....and it'd still be free haha.

I think I may have the parts stores test stuff before I take it and install it from now on though.

cbarr300 · Apr 17, 2007

Hey JT,

having alternator probs again. Power distribution box fuse is good....I haven't checked the fusible link yet though...gonna check that in the morning.

here's the rundown on the plugs' voltages.

A= 11.8 (battery voltage)
S= didn't produce a voltage
I = ~10.4

is the stator supposed to produce a voltage?

Also, I applied a ground to the ground test screw and nothing happened. Battery light is on.

any comments greatly appreciated.

Clay

HISSIN50 · Apr 18, 2007

cbarr300 said:
Hey JT,

having alternator probs again. Power distribution box fuse is good....I haven't checked the fusible link yet though...gonna check that in the morning.

here's the rundown on the plugs' voltages.

A= 11.8 (battery voltage)
S= didn't produce a voltage
I = ~10.4

is the stator supposed to produce a voltage?

Also, I applied a ground to the ground test screw and nothing happened. Battery light is on.

any comments greatly appreciated.

Clay

Hey Clay,

Definitely check the links, and the alternator fuse (a 20 amper in the underhood fuse box) again.

Try to charge the battery up because you're borderline with your ignition voltage (you can see there's a huge voltage drop there. Though not the source of your issue that I can tell, dropping more than 500 mA [from battery voltage] is not too great).

Ensure that the A terminal is really close to your actual battery voltage (within a 100 mA or so).

Now as I recall, the stator wire should show about 50% of battery voltage.

I can double check but I think one test for the stator circuit is to actually apply 12 volts to the single stator terminal wire. Don't try that without confirmation.

What you can do: Unplug both plugs on your alternator. You're going to check continuity between both legs of the stator wire. It's the middle wire in the regulator plug IIRC (double check me), and obviously the other leg is the single wire. You should see less than one Ohm across the two.

For stator circuit issues, another thing to try: Wiggle the stator fuse and see if the issue/readings change. It's not unheard of for the fuse connection to be an issue.

That's what I got for now. To confirm, the amp light is on constantly now, or is it only when you rev it? Knowing what it's doing now helps me envision what it's doing.

Good luck Clay.

cbarr300 · Apr 18, 2007

thanks for the info.

the amp light is always on. I rechecked the voltage readings (before I charged the battery) and I made a mistake earlier. My stator wire is putting out ~.88 - 1.1 at idle. It goes up to almost 2 when I bring it up to 2000 rpm.

underhood fuse is good. Now, I was looking for the fusible link, and can't find it. I see where the wire splits from one to two wires...is it in that little rubber connector? I don't think it's the fuse though because I am seeing voltage at the harness. I could be wrong though.

thanks again

EDIT: also, I checked those voltages with the asi harness unplugged. When I backprobed the ASI harness, the "I" connector gave out 2.8 volts versus the 10.8 volts unplugged

cbarr300 · Apr 18, 2007

well, went to pepboys and swapped the alternator since it was under warranty and got another one. I tried to check it on their machine but they didn't have the right plug.

While I was changing them out, I looked over the alternator cable (orange/black). I noticed it looked reallly bad on the alternator connector side. There was probably 6 strands of wire connected.

anyway long story short, all's well

Big thank you

HISSIN50 · Apr 18, 2007

Glad to hear it Clay. You hit the nail on the head with your observations. Those 6 strands of wire can show a potential of 12-15 volts, but they cannot take a load. That's why seeing how many volts you have is not real helpful with load testing.

FWIW, the fusible links look like a piece of wire that is a little thicker than the surrounding wire (it's actually ~4 gauges numerically larger, a la dimensionally smaller, than the rest of the wire it's connected to. It has a real thick insulation though).

If I didnt mention it before, my OEM cable looked crappy too. And it was dropping 400 mA at idle with no load. I ran a 4 AWG cable with an ANL fuse and it seems to work quite well.

Again, nice diagnostics. I'm glad it was something simple.

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