100 series alternator trouble? (2 Viewers)

[l3n0x]

I have a diesel, but my problem is the following: When I start the car in the morning the lights are dim & the wiper & windows move slowly. Volts are also around 11-12V. Then I drive out of my street (probably 200m's) and the lights go bright & wipers speed up, windows also - Volt meter on the dash then sits where it should be. Happens every time, but only at the first start in the morning (temperature independent).

 

[nagor]

Ok thanks for this info. I have replaced the alt with remanufactuted denso and still the problem persists. All ground connections look good. Anything else that might throw the light?

I wonder what your story ends? I have the same symptoms (lx470 2007, 132K miles): intermittent battery light flickering, sometimes voltage gauge hand goes down to 11.5V (or so) and stays there. I ran over Advanced Parts place and their scanner showed battery, starter, and the alternator is fine. I suppose the alternator is going bad slowly. But saw your post which made me thinking alternator may not be the reason.

 

[mightgetanLC]

I wonder what your story ends? I have the same symptoms (lx470 2007, 132K miles): intermittent battery light flickering, sometimes voltage gauge hand goes down to 11.5V (or so) and stays there. I ran over Advanced Parts place and their scanner showed battery, starter, and the alternator is fine. I suppose the alternator is going bad slowly. But saw your post which made me thinking alternator may not be the reason.

Hi @nagor Did you find the culprit? I had the same issues. Just installed the new alternator and still having the same issues. Getting ~11.5v with engine running. 12.6v while not running.

 

[nagor]

Hi @nagor Did you find the culprit? I had the same issues. Just installed the new alternator and still having the same issues. Getting ~11.5v with engine running. 12.6v while not running.

Hi! In my case replacing the alt helped. 45K miles since then. Did it at Toyota (turned out to be the best price for parts and labor here in Utah LHM and they even gave me a substitute car, love them). They install Denso AFAIK. Something like $700 altogether. In your case, I would go to the shop which installed yours (or find one reputable) and ask them to proceed with the findings. Might be the wiring and lots of other reasons. When it comes to car electric, I would go to professionals. Good luck!

 

[2001LC]

Some possibilities
Non OEM alternator.
Poor contact at alternator.
Poor connection(s) at battery. (oxidation, clamps)
Ground.

 

[mightgetanLC]

Some possibilities
Non OEM alternator.
Poor contact at alternator.
Poor connection(s) at battery. (oxidation, clamps)
Ground.

@nagor @2001LC Thank you both! I was in a pinch with family visiting so I went with what was available instead of the Denso…Ultima. I’ll recheck the items you’ve mentioned and also get the old alternator tested to see if it was even bad. It was completely soaked in PS fluid. On the bright side, I installed new PS hoses while I was in there!

 

[2001LC]

I'm South Denver, in DTC area. If you get up here from the springs. Stop by, and I'll look over your 100's. Just PM (DM) your contact info, so we can touch bases!

 

[mightgetanLC]

I'm South Denver, in DTC area. If you get up here from the springs. Stop by, and I'll look over your 100's. Just PM (DM) your contact info, so we can touch bases!

@2001LC small world! I’m actually in Monument, so just up and over the hill. I drove around my neighborhood for about 20 min last night and depleted my battery, so not likely to make it over to DTC. I appreciate the offer though!

The old alternator failed the bench test, so I guess my diagnosis was partially right. I managed to get a probe on the “new” alternator while it was running and measured 13.6v and then 12.6v at the battery (both at idle). I expected to see the same or very close to the same voltage in both spots, so that is odd. I’m assuming that could mean a bad connection/ground still. Also, this new alternator has a whine (not a belt squeal nor a bearing grind). I found some vids that point to a bad diode possibly, but it’s technically putting out the low end acceptable voltage. Got some more self-educating to do there.

I have a feeling I might be dealing with two issues here. 1. Voltage drop between alt/battery and 2. Crappy reman alternator with diode issue.

I sure wish the alternator was mounted right up top like a Silverado!

 

[Sventvkg]

This is serendipitous in that I got in mine today, and I heard a loud whine pop the hood I could tell something down there was whining first thing I thought alternator looked at the dash the battery light was on and the volts were definitely getting low. I went to the auto parts store, they brought out the tester said it’s a bad voltage regulator in the alternator. I picked up an alternator but unfortunately I couldn’t get a Denso. I’m gonna put it in start tomorrow and I’ll finish it Saturday as I have work. I just did my wife’s Lexus ES 350 water pump last week and it was a nightmare .

This shouldn’t be that bad. This summer I have to do the timing belt water pump and I’m gonna go ahead and put a factory alternator on there and keep this car. Quest premium alternator as a spare. Also noticed my heater tees are leaking and disintegrating, and I happen to have them as I was planning on doing them, so I’ll also take care of that. I might even do the AHC fluid which needs to be done!!

 

[mightgetanLC]

This is serendipitous in that I got in mine today, and I heard a loud whine pop the hood I could tell something down there was whining first thing I thought alternator looked at the dash the battery light was on and the volts were definitely getting low. I went to the auto parts store, they brought out the tester said it’s a bad voltage regulator in the alternator. I picked up an alternator but unfortunately I couldn’t get a Denso. I’m gonna put it in start tomorrow and I’ll finish it Saturday as I have work. I just did my wife’s Lexus ES 350 water pump last week and it was a nightmare .

This shouldn’t be that bad. This summer I have to do the timing belt water pump and I’m gonna go ahead and put a factory alternator on there and keep this car. Quest premium alternator as a spare. Also noticed my heater tees are leaking and disintegrating, and I happen to have them as I was planning on doing them, so I’ll also take care of that. I might even do the AHC fluid which needs to be done!!

@Sventvkg - Bummer! I’d HIGHLY recommend that you go ahead and get a new connector housing for the alternator plug. Yours will almost certainly break into pieces upon removal, so take note of wire arrangement for when you re-pin it. Mine was $12 at the dealership and P/N 90980-11349. I had leaky power steering hoses, so I went ahead and pulled the pump off to have room to work and replace the hoses while I was in there. While people do it, I just couldn’t get the alternator out from underneath without feeling like I was about to break things. If I have to go back to Oreillys for a replacement, I’m having them test it in their machine before I leave the store. I’m hoping to get my money back and get a Denso if possible though. Good luck with the fix!

 

[2001LC]

@2001LC small world! I’m actually in Monument, so just up and over the hill. I drove around my neighborhood for about 20 min last night and depleted my battery, so not likely to make it over to DTC. I appreciate the offer though!

The old alternator failed the bench test, so I guess my diagnosis was partially right. I managed to get a probe on the “new” alternator while it was running and measured 13.6v and then 12.6v at the battery (both at idle). I expected to see the same or very close to the same voltage in both spots, so that is odd. I’m assuming that could mean a bad connection/ground still. Also, this new alternator has a whine (not a belt squeal nor a bearing grind). I found some vids that point to a bad diode possibly, but it’s technically putting out the low end acceptable voltage. Got some more self-educating to do there.

I have a feeling I might be dealing with two issues here. 1. Voltage drop between alt/battery and 2. Crappy reman alternator with diode issue.

I sure wish the alternator was mounted right up top like a Silverado!

Tough call, since aftermarket. Do double check all connection, on alt & battery. Also make sure you did not mix up pins/wires in wire housing block. Also keep in mind. The battery may have been damaged. By over or under charging.

This is serendipitous in that I got in mine today, and I heard a loud whine pop the hood I could tell something down there was whining first thing I thought alternator looked at the dash the battery light was on and the volts were definitely getting low. I went to the auto parts store, they brought out the tester said it’s a bad voltage regulator in the alternator. I picked up an alternator but unfortunately I couldn’t get a Denso. I’m gonna put it in start tomorrow and I’ll finish it Saturday as I have work. I just did my wife’s Lexus ES 350 water pump last week and it was a nightmare .

This shouldn’t be that bad. This summer I have to do the timing belt water pump and I’m gonna go ahead and put a factory alternator on there and keep this car. Quest premium alternator as a spare. Also noticed my heater tees are leaking and disintegrating, and I happen to have them as I was planning on doing them, so I’ll also take care of that. I might even do the AHC fluid which needs to be done!!

@Sventvkg - Bummer! I’d HIGHLY recommend that you go ahead and get a new connector housing for the alternator plug. Yours will almost certainly break into pieces upon removal, so take note of wire arrangement for when you re-pin it. Mine was $12 at the dealership and P/N 90980-11349. I had leaky power steering hoses, so I went ahead and pulled the pump off to have room to work and replace the hoses while I was in there. While people do it, I just couldn’t get the alternator out from underneath without feeling like I was about to break things. If I have to go back to Oreillys for a replacement, I’m having them test it in their machine before I leave the store. I’m hoping to get my money back and get a Denso if possible though. Good luck with the fix!

I replaced a lot of wire housing block. In just one starter/SAI mod service, I replace 7. Everyone I touched, crumbled.

But I've not yet had need to replace on alternator. Keep in mind we at least 2 different alternators, depending on year. So double check P/N.
BTW: To date. Every 100 series wire housing block I've had to replaced, has P/N on it.

 

[Sventvkg]

@Sventvkg - Bummer! I’d HIGHLY recommend that you go ahead and get a new connector housing for the alternator plug. Yours will almost certainly break into pieces upon removal, so take note of wire arrangement for when you re-pin it. Mine was $12 at the dealership and P/N 90980-11349. I had leaky power steering hoses, so I went ahead and pulled the pump off to have room to work and replace the hoses while I was in there. While people do it, I just couldn’t get the alternator out from underneath without feeling like I was about to break things. If I have to go back to Oreillys for a replacement, I’m having them test it in their machine before I leave the store. I’m hoping to get my money back and get a Denso if possible though. Good luck with the fix!

Thank you for the advice. I will call Toyota in the morning for the part.

 

[Sventvkg]

Tough call, since aftermarket. Do double check all connection, on alt & battery. Also make sure you did not mix up pins/wires in wire housing block. Also keep in mind. The battery may have been damaged. By over or under charging.




I replaced a lot of wire housing block. In just one starter/SAI mod service, I replace 7. Everyone I touched, crumbled.

But I've not yet had need to replace on alternator. Keep in mind we at least 2 different alternators, depending on year. So double check P/N.
BTW: To date. Every 100 series wire housing block I've had to replaced, has P/N on it.

Thank you I will definitely check them all. In my case I knew the alternator was going because I heard a loud whine coming from it.

 

[mightgetanLC]

Tough call, since aftermarket. Do double check all connection, on alt & battery. Also make sure you did not mix up pins/wires in wire housing block. Also keep in mind. The battery may have been damaged. By over or under charging.




I replaced a lot of wire housing block. In just one starter/SAI mod service, I replace 7. Everyone I touched, crumbled.

But I've not yet had need to replace on alternator. Keep in mind we at least 2 different alternators, depending on year. So double check P/N.
BTW: To date. Every 100 series wire housing block I've had to replaced, has P/N on it.

The night I replaced those pins I got in bed and started questioning if I put them in the right order. Fortunately, it was pretty easy to confirm that I did.

Doing some testing tonight, the alternator and battery voltage were at 13.6v idling. I drove for about 20 minutes then did the same test and got 8.9v at the alt and battery. Not surprisingly, truck died within the next minute or two.

This erratic and very low output seems like further comfirmation that the alternator is faulty. I’ll go ahead and get the battery checked too, but I think (with no real basis) that even if the battery was no good, I’d still expect a good alternator to put out at least 13.x volts to the positive terminal on the alternator. I could easily br wrong about that.

Off to tearing things down again…

 

[2001LC]

Very likely bad alternator.

 

[mightgetanLC]

Well, I pulled the “new” alternator off and took it back to O’Reilly and it failed their test. I had them test the next one they were about to give me and it passed. Got it installed and now it’s running like a champ.


In case someone stumbles across this and needs ideas:

I decided to try a different method of getting the alternator out since going out the bottom wasn’t working but I also didn’t want to deal with the mess of disconnecting the banjo bolt on the PS pump. YMMV. Here are the basic steps I took after the belt and intake removal.

1. Remove 3 bolts holding PS pump in place
2. Unclip PS reservoir for more range
3. Disconnect and unbolt alternator and let it sit at the bottom of the engine bay, push towards driver side if needed.
4. You should have room to push the PS pump way down into the engine bay at this point.
5. Pull the alternator out above the PS pump. - still takes some effort, but I only wrestled with it for maybe 2 minutes.
6. Reverse the steps for installation.

I’m sure the Ultima junk will fail at some point and will use this method again.

 

[Sventvkg]

Did The Alternator Saturday. Wasn’t bad at all. Ended up getting it out through the bottom without even jacking the front up. Removed skid plate, PS pump bolts, radiator shroud bolts, coolant reservoir plus the whole air handling unit and engine cover on top.

Had to use Advance Auto premium unit as no Denso in stock. Will replace with a Denso this summer when I do the timing belt/water pump and plugs.

Also changed the heater T’s which took about 7 min. One broke apart but otherwise it was simple.

 

[SteveH]

I followed the '01 LC FSM (not right for my truck, but I have a paper copy), which said to remove the PS pulley (not the whole pump) and that gave me all the room I needed. I dropped the alternator out the bottom of the truck (tight squeeze).

Am I the only one who removed the PS pulley and not the entire pump?

 

[Sventvkg]

I followed the '01 LC FSM (not right for my truck, but I have a paper copy), which said to remove the PS pulley (not the whole pump) and that gave me all the room I needed. I dropped the alternator out the bottom of the truck (tight squeeze).

Am I the only one who removed the PS pulley and not the entire pump?

I didn’t even need to remove the pulley. All I did was take the bolts out of the power steering steering pump and move it out of the way.

 

[AllLC]

Great input here Guys as always, ive been away but im looking at replacing my alternator soon. Ive noticed some of the aftermarket brands have different amp ratings. Do any of you have any experience with this or should i just stick with the trusted Denso?