Diagnostic of 28AMP failure VRR check confusion?

Hi,

WRT my recent confirmed (now) charging system failure, I'm trying to figure out it is is the VRR for sure.

I've followed the manual in diagnostic checks - here are my findings:

1. Reg/Rect wiring harness resistance check - all is goodL
2. VRR inspection (this is where things are blurry - given Honda manual says you can only check with there meter) - results are:

Red/white to each yellow (spec is open with neg probe on red/white) - measured with neg on red/white is ~4,6 M Ohm for a 3 yellows. However if i reverse the leads (wrong per manual) i get opens.

Red/white to each yellow (spec is 7.5K Ohm with pos probe on red/white) - measured per spec yeilds 4.6 M Ohm for all 3 yellows. Way out of spec if meter used is valid.

White to Yellows (spec is open with Positive probe on white) - measured is ~ 15 M Ohm for all 3 yellows (out of spec), However if i reverse the leads (wrong per manual) I get opens

White to Red/White, Yellows (spec is 60kOhm to R/W, and 28KOhm to yellows) - measured is open for all of these which is out of spec. Of course if i reverse polarity i get the 15 MOhm (which is the same check as above).


3. Alt Inspection 3P and 2P connectors
Yellow to Yellow terminals (spec is 0-1 Ohm) - measured is .5 Ohm on all 3 - checks good.
Then it states Yellow to white terminal should be Open (assuming this is the white on the 2P) - measured is open on all 3 - checks good.
Then it states Yellow to red/white terminal should be Open - well there is no red/white in the 2P only a white and then the black wire. So if I MAKE THE ASSUMPTION that the manual meant the black wire (the only other wire in the 2P) then there is no continuity and it is good. Any one know if the manual has ERRORED?


2P connector (black to white 0 - 4 Ohm) - measured ~ 3.0 Ohm - checks good



Lastly if it looks like the VRR is the issue - that would be good as i really don't want to do 40A surgery right now - its been one of the ST bad years for me! Would anyone have a known good VRR from a 40A upgrade or is there an aftermarket VRR that may be better a more reliable design than the OEM?

Thanks,

Paul

Hi,

Can anyone confirm if the 2P connector is the field excitation circuit?

Thx,

Paul

Paul,

Rule out the stator first. Per the manual, check each of the three yellow leads on the stator side of the red 3P for continuity to a good ground point on the frame. Continuity means that AC winding in the stator is broken/shorted to ground. If that's the case there's no need to go any further. Replace the stator or upgrade. A voluntary upgrader may have one for you for the price of postage. I gave mine away some time ago.

If the stator passes the static continuity test, then do the engine-running AC check in the text file I've inserted below to confirm it's not the stator malfunctioning when hot and running. You can read the ST-O thread mentioned for info.

If the stator still checks out OK, then check the resistance in the yellow leads from the red 3P to the white 6P at the VRR to rule out a break or high resistance/corrosion in one of them. Also, the white lead from the black 2P to the white 6P at the VRR. Then and only then proceed to the VRR.

We've known for many, many years that we can't properly do the VRR check in the manual with the commercial multimeters available to us. After ruling out the stator and wiring, to check the VRR we do a controlled substitution with a known good VRR. I have a STOC loaner VRR for this purpose. Email me.

HTH

John

------------------------ file: Alternator_test_AC-DAlameda.txt ----------------------------
ST1100 28amp Alternator Stator Windings AC Check -

[Clips of posts by Dan Alameda, STOC 7791, on ST-Owners.com, 10-11May'10, in "Alternator Trouble?":
https://www.st-owners.com/forums/showthread.php?t=84285
My notes in brackets below.]

"The three [yellow] wires from the alternator to the regulator/rectifier are known issues. It is very possible to have one winding not connecting and this will give you only about 11.5 to 12 volts output - just enough to barely run but not enough to pickup the battery if it is low or run any lighting. If you continue to run with one winding not connected eventually it will cause a failure of the alternator and regulator/ rectifier."

"....the three yellow wires are from the three windings of the alternator. These are the ones that can have connection problems. To check the alternator windings disconnect all three of these wires. [unplug the red 3P connector] Set your multimeter to AC current and start your engine with these wires disconnected. Check power between any of these wires and any two wires should have voltage output typically from 50 to 80 volts ac depending on the rpm. I don't remember the voltage/rpm output but that is not too important. Any two wires should check with ac current and be at the same level regardless of which two wires you check. If you find any two wire combinations with no voltage or much lower output this indicates that you have a bad winding in your alternator. If the windings check out okay and with everything re-connected you should have around 13 to 13.8 volts DC at your battery with your engine around 4500 rpm. If you still do not have this voltage it indicates your regulator rectifier is bad."

re: the static "Alternator Inspection" continuity check of the stator windings shown in the Honda Service Manual:

"I have never had good luck doing the ground check on stator windings as is shown in the manual. I have had many stators check good this way but will break down when the engine is running due to heat, vibration etc.. The running check is far superior and you will almost always get a good test. You can also have degraded insulation on windings that will not show up in the static test and the winding will still produce power but will be imbalanced with the other windings. The running test will show this weakness and one wire combination will read lower and this is a good indication that the stator is going to fail. A stator in this condition can also ruin the regulator rectifier."

re: "To be clear... you set the meter to AC, start the ST and then touch the red probe to one yellow lead on the stator side of the disconnected 3P and then the black probe to the other two yellow leads at this connector in turn, repeat for all combinations... is that correct?" - John Oosterhuis, STOC 1058

"Yes that is how it is done. Any two of the three yellow wires will show AC output. There is a spec but I have found that if you are in the 50-80V AC range depending on rpm the most important part of the check is that you have the same output from any two of the three yellow leads. If all combinations of two wires show the same output, you are good to go. If any combination of two wires of the three show different output this means one of the windings is suspect. I am not sure if this check is in the Honda Common manual. It is the same check I use on virtually all Japanese motorcycle alternators regardless of brand, as they all use this same three wire combination from the early 1970's through to today."

John Oosterhuis, STOC 1058

----------------------------------------------------------------------------------------------------------------------

Oldschool1 said:

Can anyone confirm if the 2P connector is the field excitation circuit?

Click to expand...

Yes, the black wire in the black 2P provides 12VDC to the stator. Colored wiring diagrams here to help with that:
http://www.st-riders.net/index.php?topic=3908.0

John

FWIW - Tip: to perform the stator tests, insert the pointed probes of your multimeter into the back side of the connector until they contact the metal of the individual leads' connectors. I didn't think I'd have to explain that simple technique (shown in the Honda manual's test illustration), but a recent experience on the phone helping an STrider friend, makes me think it might be worth mentioning.

Also maybe worth mentioning: depending in your multimeter, no continuity may be displayed as infinity (resistance beyond measure).

John

So, Paul... did your stator pass the static and dynamic tests?

John

Hi John,

Thanks for the procedure. Just got back into town so going through the checks now.

1. Stator leads to ground test: no continuity (pass).
2. Working that now

accidental post - redundant with following post - now deleted

John, new results see #2 below:


1. Stator leads to ground test: no continuity (pass).
2. Stator dynamic voltage test: .5 V each combination of pairs on the stator side of the 3P connector (fail)

However - doesn't the alternator need an excitation voltage from the 2P connector via a properly functioning VRR. So if the VRR failed - the stator may not provide any voltage? All the continuity checks for the 3P and 2P connector passed per the Honda manual.

John, new results see #3 below:


1. Stator leads to ground test: no continuity (pass).
2. Stator dynamic voltage test: .5 V each combination of pairs on the stator side of the 3P connector (fail)

However - doesn't the alternator need an excitation voltage from the 2P connector via a properly functioning VRR. So if the VRR failed - the stator may not provide any voltage? All the continuity checks for the 3P and 2P connector passed per the Honda manual.

3. 2P voltage test - looking for excitation voltage: 0.0V DC with engine running. 3P connector connected, 2P not connected.

My initial thought is, because the VRR supplies this voltage (which there is no voltage) then it confirms the VRR is toast.

Thoughts on this conclusion???

For the dynamic check did you have the meter set to AC?

Look at the wiring diagram, the black lead provides switched 12v directly to the stator and also to the VRR. Check for 12v there with the ignition on.

John,

For the dynamic test i did have the meter switched to AC.

For the 2P connector - DC.

I'll check power to the VRR - good idea

thx

Paul

So by the diagram i should have a continuous 12V at the black lead in the 2P connector - and the white lead from the VRR should be the ground connection.

I'll check the black lead in 2P to ground with ignition turned on - should have 12V.

Will check tonight.

Paul

Hi John - sorry for the late response fo voltage checks (can i say schedule is out of control!)

Heres the results of the 2P connector (voltage supply side).
Results of 2P connector:

Ignition Switch off:
white to positive bat (battery) = 12V
White to negative bat = 0V
Black to negative on bat = 0V
Black to positive on bat = 12V
Black to white (both the 2P wires) = 0V ( I don't understand why these 2 are zero volts - VRR black box black magic?)

Ingition on (running):
Black to white = 0V (clearly this is the issue. (again doesnt make sense)

Measuring the input on the VR 6P connector - some had 12V supply - so assume this means the VR is powered.

Also just measuring battery voltage - it drops from 12.6V to 12.25V instantly when ignition is on (headlights not on) i thought this was an excessive voltage drop. I'm not sure the current draw is high enough to drop the voltage this much instantely. could the VR be playing a role in this?

So then - does this confirm the VR is bad since no excitatin voltage is supplied to teh 2P connnector - as in the diagrams.?

Thanks,

Paul

I'm thinking the best thing to do at this point is to plug in a known-good VRR. I'd send you my STOC loaner VRR for troubleshooting but it's currently out on loan for a few more days. I could redirect it to you if you can wait, or possibly there's another STrider following this that could help now.

John

Hi John,

I can wait. I'd like to take you up on the redirect option.

Thanks for the offer.

I will send you a PM.

Thx

Paul

Email me your snail-mail, Paul, and we'll get it in priority mail on Mon. I don't do PMs here, sorry.

John

I sent an email John - hope you got it.

Thx,

Paul

I replied, Paul. Check your inbox. Kent is mailing the STOC loaner VRR from WI today.

John

Tested with John's loaner - appears it is not the VRR.

Still had zero volts at the 2P exciter connector, battery voltage drops from 12,66V (ignition off) to 12.25V (ignition on not running) to 12.0V (ignition on running) and headlights off for all cases. I do not know if the voltage drop is normal for these conditions - intuitively I don't think the voltage should drop this amount with minimal electrical load.

I think the smoking gun is the 2P no voltage condition - yet with a known good VRR - it should have voltage. I"m going to go back and study the wiring circuit you posted again and got through it once more - pehaps it is an open or short somewhere.

Paul