Died on the starting line! Electrical issue...

[JohnJL]

Well yesterday was the first day out on the track, planned on spending the day putting some gentle kms on the engine to break her in and do some AFR tuning. It was an overall successful day (nothing broken, several MBs of datalogs, bedded the brakes in, shifting is good) but the day started auspiciously...

I was idling on the starting line for about 5 minutes waiting for our session. All of a sudden, the engine cuts out. I have power in the car and accessories but the starter will not turn over...I push her back to the paddock and find the battery is flat. A quick charge and she starts right up again and idles for 10 minutes with no problem.

I checked the datalogs, the battery voltage read 16.3-16.5 the entire time.

I did a few more sessions during the day with no problem though I was mindful of not starting until the flag was about to drop and keeping the revs up occassionally during long idle periods.

Back at home I am driving the car into the garage and again notice the "Batt" light is on.

Losing power is a pain in the staging/paddock area but really sucks if you're out on the course...would appreciate some help disgnosing this...

Some facts:

Car is stripped out and has no accessories running. THe only electrical draw is the ECU and the twin-plug ignition.

Battery is a half-size lightweight battery. Bigger than a motorcycle but smaller than an Optima.

Alternator is an external-regulator-type. THe 3-pin type regulator is a new one from our host.

Is it possible the battery is draining down even while the regulator seems to be putting out voltage (though I'm not sure of amperage?)

Good fun out at Eastern Creek though!

[carambola]

why is the voltage so high?

[lateapex911]

Yea, that voltage is way high. Cramer, and Early S man will be two very knowledgable responders here, and i won't even venture a guess as they'll make me look silly, LOL> But, at those voltages, you'll cook the battery.....IF your batt is REALLY seeing those voltages.

I'd get a digital VOM meter and start checking to be sure that reading is accurate. I'd check several locations. And I'd go over all the connections with a fine tooth comb, esp grounds, like the engine and trans ground straps.

[JohnJL]

OK, so let her idle and use a digital multimeter to check the voltage between the ground terminal on the battery and the ground strap with the ground strap disconnected from the battery (this won't fry my multimeter will it?)

Yeah, I thought those voltages were high and the battery does seem to have lost its life rather quickly...got quite hot during 4 minutes of lapping. But I though a new, properly functioning regulator should be taking care of this!

I installed new, heavy gauge and tightly connected grounds in the following locations:

Engine to trans
Alt to engine
Engine to body X 2
Batt to body
Batt to wiring harness/new fuse block.

thanks to the help

[Early_S_Man]

John,

Don't disconnect the battery while the engine is running! Your alternator can be blown out. You can use any known good battery to start the engine and test alternator output.

You can check the system Voltage at the battery or any fuse block such as in the engine compartment ... multimeter + red test lead to fuse bus, and - black test lead to a clean ground.

[lateapex911]

Right! Do NOT unhook the battery to check the running voltage. You might also want to check teh voltage at rest, (all off), idle, and a fe points up the RPM range.

Also, IIRC you should see a resting voltage of 12.6 (or is it 12.8?) at rest (all off), and (I think) 14.6 running. Ideally, thats flat thru the rev range.

[JohnJL]

OK, this is weird...

ECU logs and displays voltage at 12.5 at rest and around 16.4 while running and a little variable with engine speed.

I just checked with a multimeter and I ger 12.56v at rest and 12.17v under a high idle (1800rpm) I get that same running voltage at the battery as well as at the ignition.

Any other suggestions? Thanks All!

[Early_S_Man]

John,

The new regulator was bad, forcing output Voltage high, and may have cooked the alternator. Those latest Voltage readings confirm no output from alternator.

[JohnJL]

Ummmmm...I don't want to jump to conclusions here, but if you buy a part from a supplier and that part causes damage to your alternator, does that retailer hold some responsibility for that damage their part caused?

Hopefully there's another explanation???

thanks Warren and everyone.

[shbop]

Many electrical parts are sold without a return option. It's hard, as you can imagine, for a retailer to know what actually happened. Not to say you did anything wrong, but the retailer has to deal with all kinds of people, on a daily basis. ie- people buying the wrong part for the wrong application, and vise versa-sometimes you get the wrong part by accident.

[JohnJL]

Hmmmm...hopefully there is another explanation. I'm a long-time customer and an it a bit of a mismatch of a defective $40 part destroys a $350 part...

[Early_S_Man]

John,

The regulator was bad, and may not have damaged your alternator. A bad regulator can cause both high Voltage output and zero output.

You won't know about the alternator until it is tested ... either at a shop, or by replacing the regulator and take some test measurements while running.

[Richard Burns]

Hi John,
Glad to hear that you have finally got the car running.
As far as a warranty on the regulator is concerned it would only be covered if:
1) it was installed by the supplier &
2) if it was fitted by a qualified tradie who would have tested and found the problem before any damage was caused.

[JohnJL]

Well the supplier I bought it from doesn't do installations, so that's out...I do recall checking it with the multimeter to get continuity where expected.

I'll see how much a new regulator would be locally from the stealer on Monday.

[Walt Fricke]

You may luck out. I have a voltmeter plugged into my cig lighter, and along with some running troubles noticed 16V+ (the + is because this digital meter won't read over 16V, and just says high or something like that at that point). I replaced the VR (internal) on my '82 engine, and all was well.

I run a 914 solid state external VR on my track motor, and have a devil of a time making sure I hook it up correctly. I just have individual spade connectors, not a three pin plug. D- is easy as it is by itself, but DF and D+ are hard to distinguish though, of course, critical. And I think reversing those leads to overvoltage (remembering sulpher smells). The stenciled diagram on the plastic is hard to interpret for orientation on the other side of the unit.

Walt Fricke

[JohnJL]

I hope its so...I should say the car has been started/shut down at least 20 times and has run more than 30 minutes for initial break in and static tuning...I would have thought if something was going to burn out it would have already...

[JohnJL]

Part is superceded for a newer item according to the dealer....$179.00!!!! Can anyone help with a test procedure to determine if this one is functioning properly? That is a multimeter or battery test isolated from my alternator to see if it is a regulator or an alternator problem...

[Walt Fricke]

John

How about starting with the built-in test equipment:

1) Is the bulb OK in your alternator idiot light up in the instruments? Pull it out and test it.
2) When you turn the key to ON, does this light come on?
3) When you start the engine, does the light go off?

More than likely, if the answer to 2) is no, the regulator is bad.

If you are producing 16V from the alternator, chances are it is OK, and the answer to 3 will be yes, or at least it will get dim (the bulb doesn't care which way current is flowing - from battery to alternator, or alternator to battery, depending on what's higher than what, but 16-12 is not the same as 12-0).

Assuming the regulator is hooked up properly, of course.

Walt

[JohnJL]

Thanks Walt.

I have a driving instruction day coming up so needed to get this solved ASAP so I puled the alt last night and confirmed everything was hooked up properly. Interestingly I noted that there are two "D-" poles on the back of my alt, though only one of them was originally hooked up when the car was new (and I disassembled it and took pics at the time and labelled everything) and so only hooked up the same D- pole when reassembling. Everything matches the wiring diagrams and what was originally in the car...

I only saw your post this morning so I cant do your test but from memory:

1. The battery dash light was operating...it would come on when the ignition was turned and when the battery was showing low voltage (<12)

2. The the ECU logged its max voltage reading of 16.5 all day Saturday.

3. On sunday it logged and I measured 12.5v static on the battery and 11.17 while running.

I need to get an alternator in ASAP so I'll contact a local today but I still want to diagnose this as I have every reason to believe thus far I have a bad voltage regulator that damaged my alternator.

Any other suggestions for testing a voltage regulator?

thanks all

[Walt Fricke]

John

My knowledge of the subject is about exhausted at this point. I'd forgotten about the fact that your alternator first put out too much, and then nothing. At least it can be rebuilt (and resold, or kept as a spare).

I have a solid state regulator that I disassembled (pried the black potting material off the PCB), but I didn't reverse engineer the circuitry so I don't know what ohmmeter readings one might expect connecting this or that terminal to the probes.

Matching VRs with alternators is beyond my ken. The one for the 914 works fine on my race motor, which has an early alternator (lower wattage = less parasitic drag), but that's due to luck, not knowledge.

Early VRs are complex gizmos with solenoids and points and adjustable springs, if a person knew how to adjust.

Walt