Remy, Bosch or Denso Alternator

[sonikaccord]

Battery to engine (transmission housing) ground maybe instead of "Engine block to chassis ground"? Is there a large cable from the block to the chassis? I know there is a small one from the valve cover and power steering bracket over to the engine mount area.

The battery to chassis ground is a branch of the negative battery cable that bolts to the body right next to the battery.

Engine block is generic term in the Big 3's case. You can replace the transmission wire (the starter grounds through the transmission case), or add a wire to the actual engine block (alternator grounds through the engine block, or both if you are into overkill.

OP:
Yes your wiring harness has several grounds, typically, but they are connected through the chassis ground. Alternator grounds through the engine block/transmission ground.

Technically, the voltage at the battery *should* be the voltage from the alternator. But if you want to measure directly at the alt, you would put the black probe on the alternator case and red probe on the alternator output terminal. Then for a sanity check, I would put my black probe on the battery negative, check voltage, then black probe to somewhere on the chassis to make sure no large voltage differences are present between the three measurements.

At worst, the alternator (assuming 100 amp alternator), might put a load of about 1500 watts, which is around 2 hp, on the engine. That would be at full output, which rarely happens on stock electrical accessories.

The valve cover is isolated from the block through rubber gaskets and gromets. The little wire is simply there to keep the cover from collecting a charge. The larger wire may be for alternator ground, but I don't remember. I'd have to Google a pic lol.

[sonikaccord]

IS the oem cable 4 awg. Where approximately is the engine to chassis ground cable?

I think it may be around 4-6awg. Nothing more is necessary unless you have high demand accessories like an audio system or performance radiator fans.

[zedjr10]

Engine block is generic term in the Big 3's case. You can replace the transmission wire (the starter grounds through the transmission case), or add a wire to the actual engine block (alternator grounds through the engine block, or both if you are into overkill.

OP:
Yes your wiring harness has several grounds, typically, but they are connected through the chassis ground. Alternator grounds through the engine block/transmission ground.

Technically, the voltage at the battery *should* be the voltage from the alternator. But if you want to measure directly at the alt, you would put the black probe on the alternator case and red probe on the alternator output terminal. Then for a sanity check, I would put my black probe on the battery negative, check voltage, then black probe to somewhere on the chassis to make sure no large voltage differences are present between the three measurements.

At worst, the alternator (assuming 100 amp alternator), might put a load of about 1500 watts, which is around 2 hp, on the engine. That would be at full output, which rarely happens on stock electrical accessories.

The valve cover is isolated from the block through rubber gaskets and gromets. The little wire is simply there to keep the cover from collecting a charge. The larger wire may be for alternator ground, but I don't remember. I'd have to Google a pic lol.

Thanks. A lot of useful info. I tested the alternator today at alt. Pretty simple test. I don't know why i was so confused at first. Voltage is 12.2 at idle with all accessories on, ac on and high beams. 12.8 volts with ac button off with all accessories on. I can't test amperage. I don't have an amp clamp. So i guess it is my reman denso alt. I think i am going to get a new remy. I would get a new denso but not available and a bosch has 6 grooves in its pulley adn don't want to deal with that. Remy is oem toyota right. So am figuring it must be good.

oh yeah, negative grounds are all cleaned and cable ground to tranny is in great shape. So must be alternator right?

[zedjr10]

For future people. The alternators available for these cars have changed alot in last 8 years. Even denso no longer does the remans for these alternators alot of times it seems. AC Delco is Remy as far as alts go. Am not sure if bosch does all the remans in house. I found it on denso site in small print somewhere. I use to think they remand all the stuff in house. So basically who effn knows what you are really getting. Best to just start getting new ones and not rebuilt imo. So off to find a new boasch that will work. Never thought i would put a bosch product on this car after my experience with their o2 sensor. But germany makes some good shit for this car i have found out compared to aftermarket new stuff.

[toycar]

Bosche is super high quality

Went through the same stuff with my civic on the alternators. Denso, fine print about them not doing the work and all

O2 sensor issue is isolated

I’d trust bosche

[Fleetw00d]

Voltage is 12.2 at idle with all accessories on, ac on and high beams. 12.8 volts with ac button off with all accessories on. I can't test amperage. I don't have an amp clamp.

oh yeah, negative grounds are all cleaned and cable ground to tranny is in great shape. So must be alternator right?

What is the voltage with all accessories off at idle?

[zedjr10]

Bosche is super high quality

Went through the same stuff with my civic on the alternators. Denso, fine print about them not doing the work and all

O2 sensor issue is isolated

I’d trust bosche

I can't get the bosch al1260n anymore. Seems bosch makes them no more. What do you think about the reman al1260x. I spoke to bosch rep and he sais there are 4 factories in usa for alts and they reman them all in house. What you think?

[zedjr10]

What is the voltage with all accessories off at idle?

14.3 volts at my volt gauge so probably 14.5 or so at alternator. Goes down to 13.7 when i turn blower on. Vibration is still there at idle when ac cuts on. AM really thinking i have a bad ground somewhere.

Sometimes it will drop down to 12.5 at volt gauge cause i think battery is fully charged or something and alternator isn't producing anything. All accessories off except for radio. This is normal right? My battery light still comes on on occasion when car comes to stop light, at idle, and no accessories on.

I know the most likely ground would be the battery ground but it looks fine. Part of the ground wire is exposed and looks good. No frayed wires connecting to tranny. Am wondering if the part that is covered with rubber ok. I don't want to replace something just cause it might be as i have done this soo much on this car already. Anyone ever take this battery ground off to find out the part covered in rubber was frayed. That makes no sense to me but figure i would ask.

[wtfisafleek]

Maybe you said it before, but have you load tested your alt, say at Autozone or Napa? Considering the condition you got it in, I wonder if they sent you an old unit that was slated for reman'ing but it didn't happen?

Also, why were you even changing the alternator? Were you having problems with the charging system before that? After all, there's lots of inputs that feed into the ECU which in turn changes voltage generated at the alternator (power flow out of the alt from what I gather).

If the alternator is suspect out of its greasy box I think it would be easier to test than the other 9 inputs to the ECU. If it's faulty, a new one from Honda is actually available for the low, low price of $1077.65!

[zedjr10]

Maybe you said it before, but have you load tested your alt, say at Autozone or Napa? Considering the condition you got it in, I wonder if they sent you an old unit that was slated for reman'ing but it didn't happen?

Also, why were you even changing the alternator? Were you having problems with the charging system before that? After all, there's lots of inputs that feed into the ECU which in turn changes voltage generated at the alternator (power flow out of the alt from what I gather).

If the alternator is suspect out of its greasy box I think it would be easier to test than the other 9 inputs to the ECU. If it's faulty, a new one from Honda is actually available for the low, low price of $1077.65!

Just don't want to get stuck with something i will regret as far as alternators go. Now i am mostly wondering what other grounds i can go look at. My first thing to do is put car on jackstands and try to find those engine harness grounds but i got to wait for it to be a warmer day.