Alternator replacement/electrical issues

Hello all,

My extended warranty expired a few months ago and now I have to work on this car myself. :( I replaced the CPS a couple of months ago and now I am having the infamous electrical problems.

The headlights have flickered for years. My wife left the parking lights on a couple of weeks ago, so I replaced the battery. I figured it was about 5 yrs old and I didn't trust the charging system as it seemed the headlights were going dim for several minutes at a time, so why chance it.

Christmas Eve my wife calls me to tell me the car died. After having it towed to the house this is what I found. The battery was about completely dead. I charged the battery and started the car. Using my Fluke meter I noticed 14.5 volts at the battery. Then, the engine RPMs jump up a couple of hundred and the voltage creeps down to 12 volts and below. I notice the engine drops a few hundred RPM and the voltage kicks back up again. This is all within about 1 to 2 minutes time. It did this cycle several times just sitting in the driveway.

Either something is happening where the alternator craps out, or it is not getting pulled for anything. I guess this is why the rpms rise when the voltage drops. No load on the alternator means more horsepower for the engine. Something happens to tell it to come back on, and the load on the engine comes in. Either that, or I am totally wrong. :) :) I would hate to spend the $$$ and time to attempt a replacement (I figure Bosch) to find it is something else. Anyone else experience these symptoms? I wish these things had external regulators, as I would assume it is more of the problem then the alternator itself.

BTW...my dealer supposedly replaced the alternator under our extended warranty some time ago to fix the headlight issue, which it didn't fix. The part does look pretty clean, although I can't see too much of it.

And finally....how do I replace this thing? I am dreading removing the thermostat housing to introduce air into the cooling system. I know that would be my next project if I do. :(

Thanks,
Don

Don't know what to tell you, bud. The headlight issue is supposedly caused by the poorly designed alternator on these 3.5s. My headlights flicker with the original alternator, but I have never had the charging issue that you have. Are you sure everything is OK with the new battery? Even with all the electrical issues on this car, I have never had a dead battery or starting problem - with 70K miles and 5 years and original batter, starter and alternator. In Michigan. And the temperature just dropped here a couple of weeks ago to around 0 (yes, Fahrenheit) and hasn't risen much since then. I was waiting for the battery to fail when that happened but it just keeps on ticking!!

Do your dash lights all come on when the car acts up? I believe my alt is acting up, but when it does the dash goes crazy w/ the idiot lights all coming on and the gauges maxing out - then back to 0. After it acts up the trip odo. and the clock reset themselves also.
Did you check the connection at the alt., starter and the battery terms?

> Either something is happening where the alternator craps out, or it is not getting pulled for anything. I guess this is why the rpms rise when the voltage drops. No load on the alternator means more horsepower for the engine. Something happens to tell it to come back on, and the load on the engine comes in. Either that, or I am totally wrong. <

IMHO, this seems like a wrong assumption. The power of an idling engine is huge compared to the load of an alternator. That said, I don't know what the problem is so maybe I'm the fool!

Idle RPM should be controlled by the computer and the IAC (Idle Air Control valve). You should be able to see on a diagnostic computer the idle speed and possibly the desired idle speed that the computer wants. I have found this tool to be wonderful: http://www.obd-2.com/

> Christmas Eve my wife calls me to tell me the car died.

Can you give me details here?

IMHO, this seems like a wrong assumption. The power of an idling engine is huge compared to the load of an alternator. That said, I don't know what the problem is so maybe I'm the fool!

> Christmas Eve my wife calls me to tell me the car died.

Can you give me details here?

I am aware of the power of the engine, but understand your point. You may notice that when you turn your headlights on, or turn a blower fan on to max (without A/C on) the idle will drop slightly in most cars. This is due to load from the alternator. It takes power to make power. Disconnecting/reconnecting an alternator will make a difference in idle that will cause the IAC to have to compensate. Not only for the load from the alternator, but the voltage difference. That doesn't mean it is forever, as the system should compensate like it does from the load of an A/C compressor. It's the whole cause/effect thing. I can't prove which is which yet.

I posted on another thread an update. I forgot I started my own thread. It has been one heck of a month for me(not just the car). Maybe this new year will give me better luck. The alternator stops working for several minutes as proved by my Fluke meter. I assume that my wife was lucky enough to have it stop for more than several minutes which finally drained the battery. She had a few idiot lights come on before it finally stalled on her. A few hours of re-charging the battery and I was able to see what was going on. The dealer replaced the alternator for free as they did one in January 04. I didn't have the record on that repair, but they did. Woohoo! Because they don't like to work for free they charged me over $200 for a battery cable/harness to go along with the alternator. I thought it would be a good idea as I saw someone elses post about having a problem with the harness. Here we are 3 days later and I was able to witness the alternator not charging for over 5 minutes again. On the way back to the dealer, my wife said it was starting to act funny like it did the first time it died. No telling exactly what she meant, but she mentioned the steering. I can only assume it was the power-assist that works so well at very slow speeds.

My wife really likes this car, but it is frustrating. Once they fix the problem, we plan on putting it up for sale to get a newer car. I would like to give her my LS and get a 2005 Mustang, but I don't know if I will get that lucky. I would have hoped to keep the Intrigue for at least 100,000 miles. It's still just a baby at 80,000! :)

Also, if anyone could get a voltage reading and the amount of time the voltage dropped during the headlight flicker, that would be great. I might be dealing with a separate issue completely here now. One may be harmless and the other not.

Thanks all and Happy New Year!

this still sounds like alternator/regulator problems to me. Are you sure they replaced the alt again? Maybe they just told you that. Maybe it has a problem with the alternator wiring harness?

Hey ttbit, I just spent a few minutes looking at my factory service manual (for a 2002) and it describes how the circuit works a little bit. The Powertrain Control Module (PCM) uses a generator turn-on signal to control the alternator. A high side driver inside the PCM, (which I believe is some kind of output transistor), is responsible for turning the alternator on and off by supplying a 5 volt signal to the voltage regulator (pin B - red wire). (Not the big red wire attached to the post).

This system also stores codes for certain faults relating to these circuits. I would think a good GM tech might be able to narrow this down if codes exist. So anyway, my guess might be a bad PCM, or possibly a poor connection at the harness plug of the alternator.

One thing you might try is wiggling the alternator harness (if you can get to it) with the engine running and see if you can make it act up. If so, you probably need to repair the harness near the alternator. (We used to have to splice in new alternator harness plugs when I worked for VW all the time.)

Another thing, possibly, is monitoring the 5 Volt signal from the PCM with a (digital multimeter) that controls alternator turn-on. Being a mechanic, I would maybe try doing that to my own car if I couldn't figure out what was happening, but if you screw up you may potentially damage something if you splice in or hook up wrong.

Have somebody read the codes first of all, then clear them. And maybe have them read again and see which ones come back.

Good luck - I have wiring diagrams and a pic of the pinouts in the alt wiring plug.

Good info! Thank you. If you can send me any pics/diagrams to my djperuski at comcast.net I would appreciate it. Been getting a lot of spam lately, so I have not been posting the email as a link. :)

The alternator is as shiny as can be, they replaced the positive lead harness, and there is steam coming off of the radiator, so I assume they did the job, just maybe not correctly or it was mis-diagnosed.

The car is sitting at the dealer now, otherwise I would be looking for that 5 volt signal right now. I wonder why that exists? Possibly in case the alternator/regulator is producing too much voltage?

Thank you again,
Don

I tried sending you those images - apparently your email server is not accepting the message

there is an new alternator design for the 3.5L :P/N 10464469

for cars with the air pump there are 180 amp alternators available.

from AlldataDIY:


2000 Oldsmobile Intrigue V6-214 3.5L VIN H SFI

Top - Vehicle
Starting and Charging
. Charging System
. . Alternator
. . . Technical Service Bulletins
. . . . All Technical Service Bulletins
. . . . . Headlamps/Interior Lamps - Dim Intermittently

.



Notes


Headlamps/Interior Lamps - Dim Intermittently

File In Section: 06 - Engine/Propulsion System

Bulletin No.: 01-06-03-001A

Date: April, 2002

TECHNICAL

Subject:
Headlamps/Interior Lights Dim Intermittently in Cold Weather
(Replace Generator)

Models:
1999-2002 Oldsmobile Intrigue with 3.5L V6 Engine
(VIN H - RPO LX5)

This bulletin is being revised to add VIN breakpoints and to include information on 2001-2002 vehicles which may exhibit a similar condition. Please discard Corporate Bulletin Number 01-06-03-001 (Section 06 - Engine/Propulsion System.

Condition

Important: Short term voltage drops (flickers/fluctuations of lights) may occur whenever high demands are placed on the vehicle's electrical system. This is considered a normal generator output characteristic and a repair may not be necessary. Some owners of the 1999-2001 model year Oldsmobile Intrigue built prior to VIN breakpoints 1F237068 may comment on an intermittent condition where the headlamps or interior lights may dim intermittently. This condition may also be noted in the blower speed slowing or changing pitch intermittently. Some 2001-2002 model year vehicles built after the VIN breakpoints may exhibit a similar condition.

Cause

On 1999-2001 vehicles built before the VIN breakpoints, this condition may be caused by intermittent low voltage. Transient engine vibrations may induce the generator to experience field discontinuity. This state results in a voltage spike that causes the voltage regulator to reset. During this period, the electrical system drops to battery voltage.

On 2001-2002 vehicles built after the VIN breakpoints, the voltage drop may be due to the electric AIR (Air Injector Reactor) pump cycling. This electric pump causes a large current draw when it starts.

Important: At no time during the above conditions will the headlamps go out.

Correction

On 1999-2001 vehicles built before the VIN breakpoints, replace the generator with a revised generator, P/N 10464469, that has circuitry to inhibit the voltage regulator reset condition. Use the procedure below to replace the generator.

On 2001-2002 models built after the VIN breakpoints, do not attempt any repair to the vehicle. This is a normal condition of the vehicle and does not indicate the need for service. If the customer requires reassurance that this is a normal condition, please refer to the AIR pump demonstration section below.

Important: 2000 model year California and Northeast states emission equipped vehicles and all 2001 Intrigues are equipped with the electric AIR pump. After generator replacement, these vehicles may still exhibit very short dips and/or headlamp dimming due to the AIR pump cycling. Refer to DTC P0410 in the Engine Controls sub-section. If the generator has been replaced, any short term headlamp dip should be considered normal. If the customer returns a vehicle that has been corrected with a generator replacement, you may reassure the customer by demonstrating the condition. Refer to the AIR pump demonstration section.

Anyone replace the alternator themselves in this thing? Looks like a real PITA as there is not much room to work in there. Looks like you get to perform cooling system maint at the same time as you will need to pull off the hoses to get in there.

Hey all,

Here is an update. The dealer replaced the alternator again and when I drove it home I saw no headlight flickering. It has been a couple of days and I haven't had time to drive it again to test, but will be keeping an eye on it. My wife says the steering feels funny like it did the first time before the car died. I believe she is talking about the steering assist where it is very easy to turn when you are parking or at slow speeds. I noticed that it seemed different also. Is this electronically controlled? Maybe it is related? I will have to check for a bad connection/short, I guess.

I really appreciate all the input I have received on this thread. Very useful stuff. I don't think the service guy I spoke to at the GM dealer knew what a TSB was. :shakehead He said he has never heard of alternator problems. It could be they replaced the last one with the updated version, but good service is very hard to find around here.

kmohr3: Were you trying my djperuski at comcast.net account?

My wife wants my LS, so we will be selling the Intrigue. I want to make sure we get this stuff worked out first though.

That didn't take long. Broke again today and stranded my wife and son.

My sympathies for your Intrigue...... Please let me know what repair finally fixes your Intrigue, good luck. I hope the diagrams help you out. Did they check for codes?? You may want to call GM, they should have a phone number for customer concerns. Also, is there another GM dealer nearby that might be more knowlegeable than these guys?

That didn't take long. Broke again today and stranded my wife and son.


You never posted a "Fixed" post for your generator problems. I am having flickering and overcharging. The old alt. was overcharging, but would reset at 16.5V.

I replaced the alternator and it immediatly started charging at 15.5 this worked for a day and then after the weend when I went home it was chargine at 17V and above.

I replaced both of the wires to the PCM (Except the plugs) it was working perfectly until I tried to come home from work, Back to 17V. The only other wire to the alt. was a hot at all times. I took out the fuse for the generator (hoping to drive home on battery voltage)

To my surprise, it started charging at about 14.5V This shouldn't be. I would be happy with just leaving it this way, but I know it will just stop charging at one point.

What Fixed Your Problem?

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