I have gone thru the codes section and searched thru archives but still come up stumped.

I just picked up a 86 V6 5-speed car. Car sat for about a year. First thing it needed an altenator, car wasn't charging, about 9 volts. I put a new altenator in and then it was fine for about a 1/2 mile down the road, then Volts jump to 18 and the engine light pops on (code 32, high voltage). Thought by chance I got a bad remunufactured altenator, got another one, I am on the 3rd altenator and the problem still exists, so I am trying to find the problem.

I know code 32 could also be EGR related, but the volts gage reading 18 makes me think it high voltage.

Any ideas, or similiar experiances on what I can look for. Dont' car for computer controlled cars, I like my old pre computer cars, easy to work on.

thanks

Bruce
Rat427@aol.com

 

If the alt is high charging I would suspect a bad battery. Lead acid batteries will start to develop high internal resistance when they are on thier way out, hence the alt will run ***** to the wall to try to charge it. When the batt resistance is high it will not fully charge. First thing to do is get a cheap voltmeter and check the charging voltage at the battery to confirm the guage accuracy. If confirms your guage, the disconnect the battery and try to trickle charge it. An alternator is NOT a battery charger and will not recharge a low battery. Try these two things and you will probably solve your problem.

 

either the voltage regulator inside the alternator has failed or the voltage sense tab for the regulator does not have good electrical contact with the battery.

 

2V, I would agree with you except for the fact that he is on his third alt. 86 I believe is the 10Si series that has an internal regulator. If he got three bad ones I would find another vendor.

 

agreed if the battery is of unknown condition and age, it's probably a good idea to replace it. a bad battery can kill a new alternator which would explain why three alternators were installed in such a short time frame. but it is puzzling how a bad battery would cause an overcharge condition.

if you want some more info on batteries, check out the "CAR BATTERY & DEEP CYCLE BATTERY FAQs":

http://uuhome.de/william.darden

 

Actually I have instructed technicians over the years about the do's and don't's pertaining to lead-acid batteries. In our remote transmitter sites many of the repeaters use them as backup when commercial power is lost and they get babysat quite a bit. The reason I wanted to know what actual voltage he had was important. Most alternators will begin to throttle back when they hit above 16 volts to protect the auto's electrical systems so accuracy is important to a diagnosis. Resting terminal voltage, and charging terminal voltage can tell you a lot about the condition of the batt.. An alternator uses voltage to determine it's rate of charge. This is done internally in most cases by the regulator. The reg uses a resistor bridge or zener diode to sense voltage. The manufacturer set's a target voltage in the regulator based on how they want the battery to charge. It is very possible to have a lazy cell which would cause the terminal voltage to stay lower than the target voltage the alt. want's to charge to. In this case the alt will run wide open trying to charge a batt that will never come up. This is actually a fairly common occurance and is why in many cases a dealer will replace the battery any time an alternator is replaced. My wife just went through this with her Blazer, same set of conditions. Modern car's hit the battery with high current as soon as it starts to run. This actually cut's the battery life very short. It also does not provide the kind of charge that a slow trickle will provide. Trickle is ideal at about one-tenth of C, C being the battery's capacity in ampere hours. The guy who put up the post could very well have a third bad alt but in all reality that would be a stretch. He has something else going on. Batteries are pretty interesting bird's, and over the years I have seen them do some pretty strange things. I do agree with you that 18 volts doesn't make sense because even if the reg were bad the batt normally will hold at about 16 volts, if he were hitting it with 18 for any period of time it would probably explode. I usually give mine a slow trickle once a month, and maybe you heard this from me before but my original batt from the rock is still running the kid down the street's 86 bird. TNX for the web address, I'll check it out.

 

UPDATE - - - - Still no luck.

This time I tried the new battery from my race car and another altenator. Fired it up, looked good, for about 4-5 minutes, then the volt gage started climbing till it hit the red zone and popped the engine light on. We checked voltage of the battery when running and volt gage was reading 17.4. (WTF). I have also cleaned all the grounds, etc., Any other suggestions before I take this thing up to a shop and have to pay for them to diagnos it.

I have been working on cars for years, mostly pre (dam) computer. If this happen, usually one of the above listed solutions would work. This one has got me stumped. Only thing I can think of is it might have a bad computer (or something) that is telling the computer that the voltage is low and it is telling the altenator to charge more.

 

The ECM has nothing to do with charging. When you check the voltage are you measuring it right at the battery terminals? At 17-18 volts you will eventually smoke the electronics. I would not believe it but take the alt to a shop taht will test it for free, and see what they say. Many parts stores provide this service. Let me know.

 

Well,hi there i'm Marc from holland (Europe) i have also an
transam from 1986 and i also bought a new alternator (orginal and very very new so no rebuild one) it costs me about 475 guilders that about $200.and then it begans......

I installed it myself with the old battery and i drive fine but afther 2 days when i got to work al my light went go up and my voltage got up to about 16.3Volts.....

In the evening i go to this site and ask in a topic it can hurst ?
NO NO said eveyone in this topic (sorry for the bad englisch)

But now afther about 6 moths i started worried and ill go back with the alternator and yes YES ITS No GOOD 16.3 VOLTS !!! it has to be max 14.8Volt or like that (I the meantime i replaced also my battery)

The store i was for my alternator was very very kindly and tested for free and yes there was the problem YES he didn't know of the regulator was broken so he replaced anyway...but when he tested it again yeah.... there it was i saw a spike on his scopem in the diodetrio bridge YES 1 diode was BAD he replacec it also and now

I'll NEVER HAD (tot nu toe in dutch) problems anymore with my alt it's clearly loads the battry with 14.5Volts and if i have everything on my voltage drops to exaclty 13Volts how it should be....

Greetz from Marc in HOLLAND (Europe)

**** i had to replace the waterpump and hose now my brakes in the front with the discs are replaces and **** **** now ill have also to replace the how should i say it in dutch ''mijn fusee kogels'' i think you call it steering knuckle is no good i have also to replace it.what i wan to say is that DRIVING A CARE LIKE THIS IS MAKING ME A POOR MAN In A COUPLe OF MONTHS (NO JOKING) hahaha

see you next time maby....

bye bye

(RSPONCE PLEASE) also on:

e-mail: captain.software@wanadoo.nl

 

Still fighting with this problem. I gave up for a while to finish my pro street project. Still way high voltage. 6 altenators and 3 new batteries. I had the altenators tested before I took home, tested fine. Got home, put on the car, instantly 17.4 at the battery. Can the computer control voltage at all, decide if its reading low, to increase the output (just a thought) Also, can someone measure the diameter of their altenators pully on an 86 V6. I change this to the one that is one the car, maybe someone put the wrong on at one time and I am spinning the thing way too fast.

I am ready to take this 200.00 car and have a nice bon fire (which it may do on its own if I can't solve this problem)

Thanks

Bruce
Rat427@aol.com

 

Have you tried tracing the sense wire? It is the only possibility left. If the sense wire is low with respect to the battery it will force the alt to generate tons of output.

 

Which wire is the sense wire (color if possible) and where does it run to, going to pull my wiring diagrams out later to try to figure it out.

thanks,

 

In most cases it is the brown wire in the two wire plug. I am not quite sure when GM changed to the CS alternators but I think it was late 86 early 87 models. You either have a 10si or a CS style, but most likely it will in fact be a 10si unit. According to Chilton, the sense lead is fed from two points, differing from the later models. They show the brown wire(sense) coming from a point in the instrument cluster fed by the guages fuse in the fuse block, and a resistance wire going back to the battery via the ignition switch. If one of these feeds has a problem it may force the alt wide open very similiar to doing a full field test.

 

I pulled out a wiring diagram and you are right the brown wire will be the one to chase down. Is the wire itslelf the resistor, or is there a resisitor somewhere inline I have to find. My diagram just shows a square and the word resistor written next to it. At that point it splits from brown to a brown wire leading to the gage, and a pink wire that goes to the fuse panel & the other side of the gages. Any idea were this juntion is onthe car.

thanks,

 

Still Banging my head against the steering wheel.

Basically pulled the entire dash out, chase down all the wires, can't find any resistor in the brown wire. Only place I couldn't check was on the trany were this harness drops to. I could pull on the wire on each end of the wire loom, is not bound or hooked to anything. I even swapped out the volts gage for a spare.

I am still getting the high volts. The longer I let the car run trying to check stuff the hotter the altenator is getting (hot to touch, motor is not)

Please help.............

 

I need to know for sure what alt you have but most 86 models were equipped with the 10si Delcotron. Found my old manual for servicing the Delcotron. I am quoting , 1) with a voltmeter and plug removed, key on engine off measure the BATT, Pin 1, Pin 2 connections at the Delcotron using engine ground. All terminals of the Delcotron should read battery voltage(approx 12 volts). Troubleshoot any line which does not read battery voltage.2) An open on pin #2 of the plug will cause uncontrollable output voltage from the Delcotron causing damage to battery or electronics. Sounds like it, huh. You must trace that #2 wire, or if you can't find it post me and I will tell you how to fudge it. The resistor may be a resistance wire and they are usually crimped in place similiar to a fusible link. Some resistors can be mounted on the firewall. Keep the faith, we'll find it.

 

It finally runs, Thanks for all the help.

This is what it finally was. I started checking each wires voltage like you suggested. Got home, pulled the plug, turned the key to on posistion, brown wire 12v, red wire 12v, WTF. I started the car gage was reading 14v for 3 seconds, then climbed over 18v. Turned car off, checked wires again, brown wire 12v, red wire 0.

OK, now to trace the red wire. Dug my diagrams out and pulled and tugged for a while. Red wire leads down to starter and there are 3 fusible links there. Couldn't get to them to check without pulling started. Starter solonoid falls to pieces when I try to remove wires. So while I had the starter out I replace all fusible link anyways and had to buy a new starter.

Charging system is perfect now. either fusible links were dropping out after they heated up ar the started was creating some type of short after starting.

anyways, the car is finally drivable. Thanks,

Bruce