Alternator changed and ensuing Christmas tree on the dash.
02-02-2012, 02:13 PM
#1
Rennlist Member
Thread Starter
Alternator changed and ensuing Christmas tree on the dash.
Just to start with, I work on 928's daily and the 996 is a different bird to me. I've worked on a few so you'd think that changing an alternator would be a simple deal with no issues. So here is a short story.
Have a guy that was recommended to me from a customer, '01 996 tip with a bad alternator. Now I was told the battery had been going dead quickly and was unable to be jump started. This apparently has been going on for some weeks and the owner just parked it and left it until I could get the time to check it out.
I get to his house and we put in a new battery, car fires right up and the alt is not working at all. Sucking down the battery as one would expect it to. So I get a Bosch reman like everyone usually does, install it, car fires and charges fine. I leave and get a phone call later in the day saying his speedo (both digi and analoge) are inop, odo inop, the spoiler light is on (it does go up and down), check engine light, and the ABS light. Radio doesn't work but I'm sure that is the fuse behind the radio. These all stayed on during his 15 mile drive. The car is running great he says.
Need some thoughts and some assistance.
Have a guy that was recommended to me from a customer, '01 996 tip with a bad alternator. Now I was told the battery had been going dead quickly and was unable to be jump started. This apparently has been going on for some weeks and the owner just parked it and left it until I could get the time to check it out.
I get to his house and we put in a new battery, car fires right up and the alt is not working at all. Sucking down the battery as one would expect it to. So I get a Bosch reman like everyone usually does, install it, car fires and charges fine. I leave and get a phone call later in the day saying his speedo (both digi and analoge) are inop, odo inop, the spoiler light is on (it does go up and down), check engine light, and the ABS light. Radio doesn't work but I'm sure that is the fuse behind the radio. These all stayed on during his 15 mile drive. The car is running great he says.
Need some thoughts and some assistance.
02-02-2012, 03:30 PM
#2
Race Director
Just to start with, I work on 928's daily and the 996 is a different bird to me. I've worked on a few so you'd think that changing an alternator would be a simple deal with no issues. So here is a short story.
Have a guy that was recommended to me from a customer, '01 996 tip with a bad alternator. Now I was told the battery had been going dead quickly and was unable to be jump started. This apparently has been going on for some weeks and the owner just parked it and left it until I could get the time to check it out.
I get to his house and we put in a new battery, car fires right up and the alt is not working at all. Sucking down the battery as one would expect it to. So I get a Bosch reman like everyone usually does, install it, car fires and charges fine. I leave and get a phone call later in the day saying his speedo (both digi and analoge) are inop, odo inop, the spoiler light is on (it does go up and down), check engine light, and the ABS light. Radio doesn't work but I'm sure that is the fuse behind the radio. These all stayed on during his 15 mile drive. The car is running great he says.
Need some thoughts and some assistance.
Have a guy that was recommended to me from a customer, '01 996 tip with a bad alternator. Now I was told the battery had been going dead quickly and was unable to be jump started. This apparently has been going on for some weeks and the owner just parked it and left it until I could get the time to check it out.
I get to his house and we put in a new battery, car fires right up and the alt is not working at all. Sucking down the battery as one would expect it to. So I get a Bosch reman like everyone usually does, install it, car fires and charges fine. I leave and get a phone call later in the day saying his speedo (both digi and analoge) are inop, odo inop, the spoiler light is on (it does go up and down), check engine light, and the ABS light. Radio doesn't work but I'm sure that is the fuse behind the radio. These all stayed on during his 15 mile drive. The car is running great he says.
Need some thoughts and some assistance.
'course, I assume a thorough double-check of the alternator installation and wiring hook ups/connections and the battery cabling (not only at the battery posts but wherever the cabling runs and where the cabling connects) has been done?
Also, if the car sat any length of time -- and this can be just a few days -- rodents may have been at the car. Check very carefully all through the car and on top of the plastic panels under the car for any signs of rodents: Nesting trash, or worse.
Sincerely,
Macster.
02-02-2012, 03:41 PM
#3
Rennlist Member
+1 on connections/wire continuity & isolation
Also disconnect/reconnect the battery to see if this "resets" things. Check for bad diode letting AC through? Could show up as battery drain back through Alternator even when not running.
Also disconnect/reconnect the battery to see if this "resets" things. Check for bad diode letting AC through? Could show up as battery drain back through Alternator even when not running.
02-02-2012, 03:54 PM
#4
Rennlist Member
Thread Starter
I spent a few hours last night searching and didn't come up with anything but today I find that the ABS/check engine warning might possibly be due to the MAF. Since I did remove the MAF to change this out, I'm hoping it's as simple as needing to ensure the plug is in all the way.
I'll update this as soon as I get that checked.
I'll update this as soon as I get that checked.
02-02-2012, 04:01 PM
#5
Bad case would be ignition was on when connecting the battery. Heard that could damage computer brain.
Extra input is check the fuse box for funny additions gone wrong and signs of somebody jabbing a jumper cable onto the post in there and fouling something up. Maybe just a fuse blew.
Like mentioned diodes turn an alternators a/c into dc. Leaking a/c drives computers strange making the perceived sensor outputs all goofy. Last year a loose or miss wired alternator and such had symptom like yours of dash readings being from the twilight zone.
On the trouble shooting side of hind sight there's with and without bad install. Install went right what would be the problem that could possibly take out the alternator in time like a bad drain ie short or resistor in the system that has lost it's resistance. Fuel gauges operate with a set value resistor. Can't forget the dreaded ignition switch is flaky ie looks great after install but a twist here or there with a bump and or jiggle and walla your screwed with the same symptoms you are looking at now.
Extra input is check the fuse box for funny additions gone wrong and signs of somebody jabbing a jumper cable onto the post in there and fouling something up. Maybe just a fuse blew.
Like mentioned diodes turn an alternators a/c into dc. Leaking a/c drives computers strange making the perceived sensor outputs all goofy. Last year a loose or miss wired alternator and such had symptom like yours of dash readings being from the twilight zone.
On the trouble shooting side of hind sight there's with and without bad install. Install went right what would be the problem that could possibly take out the alternator in time like a bad drain ie short or resistor in the system that has lost it's resistance. Fuel gauges operate with a set value resistor. Can't forget the dreaded ignition switch is flaky ie looks great after install but a twist here or there with a bump and or jiggle and walla your screwed with the same symptoms you are looking at now.
02-21-2012, 07:31 PM
#6
Rennlist Member
Thread Starter
Forgot to update this one for the search archives.
After being assured that all fuses had been checked by the owner, I get there with the Durametric in hand, hooked it up and the ABS computer was not reading. Replaced the fuse and everything started to work properly. ABS/Speedo/spoiler/ and check engine all operational.
The fuse on the back of the CDR 220 was blown so that was an easy fix.
In short, if stuff isn't working, check the fuse box really well.
After being assured that all fuses had been checked by the owner, I get there with the Durametric in hand, hooked it up and the ABS computer was not reading. Replaced the fuse and everything started to work properly. ABS/Speedo/spoiler/ and check engine all operational.
The fuse on the back of the CDR 220 was blown so that was an easy fix.
In short, if stuff isn't working, check the fuse box really well.
