Builds 76 Fj40 Face Lift (16 Viewers)

[78fj40mg]

@Chungas Revenge hey buddy sorry to put such a heavy burden on your thread, please forgive me.
A very perplexing day to say the least, I hope you're still holding your position because that's where I need to be right now.

So I decided to help out a friend by sympathetically conducting similar tests on my VR, so here are my test findings.

VR testing Pic 1 engine off Lights Off ~ Batt Voltage

Pic 2

Pic 3

VR testing Pic 4 engine ON at 1800 RPM Lights On

Pic 5

Pic 6

VR testing 7 engine on at 1000 RPM Lights On

Pic 8 VR adjusted several times as per the FSM with similar results no appreciable charging

VR test pic 10 after several adjustments no appreciable charging

pic 11

Pic 12 Brand New Voltage Regulator from O'Reilly's purchased today

installed

Pic 14 New VR testing 1000 RPM Lights On voltage fluctuation 11.72 V - 11.73 V

pic 15

I didn't know that this problem existed with my VR and new alternator, any advice?

This explains as to why my previous Optima battery died a cruel death.

So needless to say...Missouri Loves Company!

 

[Chungas Revenge]

So needless to say...Missouri Loves Company!

Well doctor it seems as if we concluded similar results...Theories?

 

[78fj40mg]

I'm stumped! Hoping some knowledgeable heavy weights will chime in and clear the murky waters, i.e. our friends @bj40green @Coolerman etc.

 

[JohnnyC]

I hated my VR

Had a guy help and install a solid state VR from an 80's crown Vic

You must have read thru this thread by now:

Voltage Regulator (ext.) / How it works

 

[thebigredrocker]

Strange that your voltage was lower at 1800 rpms. Hopefully @Coolerman will swoop in to save the day.

I am guessing you tried tightening the piss out of your alternator belt. Perhaps some Gasgacinch belt dressing might be worth a try. It's nice and sticky. Maybe even scuff up your pulley's with a scotch bright pad.

 

[bj40green]

@78fj40mg Bloody good write up! Congratz!
Picture #4 tells the following:
RPM is 1800, Lights are "on", Ammeter shows 0 Amp, Voltage is 11.7V
Conclusion: The alternator is providing the Amps for the lights, ignition etc. However the voltage is too low to put out more juice (Amps) to charge (replenish) the battery. When the voltage is higher, the alternator puts out more Amps and divide it's output between the electrical system and the battery. You said that you tried to adjust the VR and no noticeable change. Hmmmmm.
It takes a lot of force to bend that regulator arm just 1 tenth of a mm.

If you think you did it right, it's time to test the alternator.
NOTE: yours is a 6 wire VR. Make sure you're bending the lip from the correct arm that moves between the contacts.
Both coils look similar, but the other one is the Voltage Relay and has a different function.

Engine "off".
Disconnect the VR.
Make a jumper wire between IGN and F on the harness connector.
Hook up your voltmeter to the battery.
Start engine but don't rev up (voltage should be a bit over 12V).
WARNING: Your VR is now out of business and your engine rpms are now controlling the output of your alternator!
Rev up slowly and watch your voltmeter.
Voltage should go up with the rpms.
Stop when the voltage is 14.8 V.
Go back to idle.
Turn on your headlights.
Rev up slowly and watch your voltmeter.
Voltage should go up with the rpms.
Stop when the voltage is 14.8 V.
Your alternator is OK.
If voltage doesn't go up, your alternator has a problem. Most likely one (or more) diode(s) are defective.

Rudi

 

[Honger]

Can we just call Rudi the "voltage whisperer"?

 

[ginmtb]

After seeing your guy's woes I decided to try this test as well. I've been having problems with my cruiser starting - battery voltage drops a fair amount (under 12 into the low to mid 11 range can't remember exactly) but eventually it starts after many tries.

Here is my battery voltage at rest, no lights:

With engine on at 1,800 RPMs. So it's definitely getting a charge:

The ammeter definitely was to the right of the midline, another good sign of charging. So there is hope for you guys but not sure what the answer is. I hope you find it. I know how annoying these problems can be...

Btw I have a remanfactured Toyota VR.

 

[Chungas Revenge]

With engine on at 1,800 RPMs. So it's definitely getting a charge:

Sweet spot^^^.

Haven't dialed it in yet. I'll try the new (rebuilt Toyota) VR and post up the results. Starting to suspect that the alternator is the culprit.

 

[Chungas Revenge]

I'm stumped!

@78fj40mg

Cold Beverage says it's the alternator.


1800 RPM, 11.67v off the alternator no lights. 10.2 with lights on same RPM. @ 1200ish RPM I Removed the POS (+) battery cable and the mule took a nose dive choked once and died....Old school test, but I'm pretty sure its my ALT.

 

[Chungas Revenge]

I have an original 76 carb. With a gasket in place it still didn't "sit" just right. Picked up a spacer and test fit. Air cleaner seems to have a better stance and a better seal with the spacer.

 

[Chungas Revenge]

it starts after many tries

@ginmtb

R U running points or electronic ignition?

 

[ginmtb]

@ginmtb

R U running points or electronic ignition?

Electronic - trollhole carb and dizzy.

 

[cruiserkev]

I have an original 76 carb. With a gasket in place it still didn't "sit" just right. Picked up a spacer and test fit. Air cleaner seems to have a better stance and a better seal QUOTE)

I have the same issue on my 5/76 carb and need to try this. Where did you get the spacer?

 

[78fj40mg]

@78fj40mg

Cold Beverage says it's the alternator.


1800 RPM, 11.67v off the alternator no lights. 10.2 with lights on same RPM. @ 1200ish RPM I Removed the POS (+) battery cable and the mule took a nose dive choked once and died....Old school test, but I'm pretty sure its my ALT.

View attachment 1411472

I suspect a faulty new alternator as well, can't do anything about it now it will have to wait after my up coming surgery. I'm revved up and pooped out now.

 

[Chungas Revenge]

@cruiserkev

Picked up the spacer from city racer.

 

[Chungas Revenge]

surgery

Ouch...! God speed sir!

 

[cruiserkev]

Thanks!

 

[bj40green]

1800 RPM, 11.67v off the alternator no lights. 10.2 with lights on same RPM. @ 1200ish RPM I Removed the POS (+) battery cable and the mule took a nose dive choked once and died....Old school test, but I'm pretty sure its my ALT.

Your conclusion is correct if................ there is voltage on the F terminal on the alternator (from the VR).
If there is no voltage on the F terminal, the alternator acts as if the battery is full and there is no output.

So, no voltage on the F terminal = alternator doesn't charge. Engine dies when + battery is removed. Check out why there is no voltage from the VR to the F terminal on the alternator.
yes voltage on the F terminal on the alternator and the engine dies when + battery is removed = alternator is defective.

Rudi

 

[Chungas Revenge]

Check out why there is no voltage from the VR to the F terminal on the alternator.

Will do!