Charging Problem - need help from the proz
#1
01-01-2008, 08:16 PM
Charging Problem - need help from the proz
I've been experiencing a charging issues that I hope you guys can help me think through. I'll explain the symptoms and then what I've done.
Symptoms: Start vehicle and alt does not charge initially. Tach does not move off 0. After 15 seconds (in warm weather), the alt will begin to make a whilr and the tach needle will rise to where it should be. It was always 15 seconds in warm weather, you could count off the seconds. In cold, sub-freezing weather, it takes much longer, like 5 minutes. Once it starts to charge, all is ok, unless ya turn on enough accessories, like the lights and fan on high. Then the alt will stop charging and the tach needle will fall to 0. Turn off the accessories and the tach will rise and alt begin charging.
What I've done: The autozone test (on vehicle) indicated the Alt failed the diode test. I replaced the diode assembly and also the brush/regulator assembly. Everything else in there looked good. It passed all the alternator tests at Autozone (off vehicle). However, it still acts the same way, even with a different (known good) battery. I also checked and cleaned the cable ends and where they attach on the vehicle. Reason I rebuilt the Alt versus replacing is: 1) I like to dig in and get my hands dirty. I've rebuilt several at a fraction of the cost of a rebuilt and never hand one NOT work. 2) I wanted to keep the original alternator on the vehicle.
Anyway, it still acts the same way as before. My question is if there is any other assembly on the vehicle that can affect alternator charging (ECM?)? Why would the alternator always begin charging at the same exact time interval? I mean, you could count the seconds at it begins charging at the same amount. And, why would the delay get longer (but still consistant) in cold weather? My mainstumbling pointis I don't want to shell out $260 some dollars for a rebuilt alternator and potentially find out it acts the same way as what I've got.
Any ideas? Have you seen this before? Suggestions? Does anyone have a charging wire diagram to see what other components might affect alternator output? Your help MUCH appreciated. Thanks
Symptoms: Start vehicle and alt does not charge initially. Tach does not move off 0. After 15 seconds (in warm weather), the alt will begin to make a whilr and the tach needle will rise to where it should be. It was always 15 seconds in warm weather, you could count off the seconds. In cold, sub-freezing weather, it takes much longer, like 5 minutes. Once it starts to charge, all is ok, unless ya turn on enough accessories, like the lights and fan on high. Then the alt will stop charging and the tach needle will fall to 0. Turn off the accessories and the tach will rise and alt begin charging.
What I've done: The autozone test (on vehicle) indicated the Alt failed the diode test. I replaced the diode assembly and also the brush/regulator assembly. Everything else in there looked good. It passed all the alternator tests at Autozone (off vehicle). However, it still acts the same way, even with a different (known good) battery. I also checked and cleaned the cable ends and where they attach on the vehicle. Reason I rebuilt the Alt versus replacing is: 1) I like to dig in and get my hands dirty. I've rebuilt several at a fraction of the cost of a rebuilt and never hand one NOT work. 2) I wanted to keep the original alternator on the vehicle.
Anyway, it still acts the same way as before. My question is if there is any other assembly on the vehicle that can affect alternator charging (ECM?)? Why would the alternator always begin charging at the same exact time interval? I mean, you could count the seconds at it begins charging at the same amount. And, why would the delay get longer (but still consistant) in cold weather? My mainstumbling pointis I don't want to shell out $260 some dollars for a rebuilt alternator and potentially find out it acts the same way as what I've got.
Any ideas? Have you seen this before? Suggestions? Does anyone have a charging wire diagram to see what other components might affect alternator output? Your help MUCH appreciated. Thanks
#2
01-01-2008, 08:46 PM
RE: Charging Problem - need help from the proz
I have never rebuilt a alt, but I JUST bought a rebuilt from AutoZone for $185 with lifetime warranty. I mean I ordered it last Wed and installed after it came in on Fri. Under 30 min and I was done. And it is still a MagMalli (ok, I know I spelled it wrong). My bearings went out on my alt onChristmas day with 150 miles left in our trip,at nightand snowing.
I dont think a bad ground would care how long the trk was running, I would tend to say it is the alt. And it takes longer in cold weather because it takes longer for the alt to warm up.
Do you know someone with a Disco and you can switch with their alt to confirm that it will or will not still act up with a known good alt?
Otherwise these guys have used ones for $75.
http://www.autosportsunlimited.com/index.html
I dont think a bad ground would care how long the trk was running, I would tend to say it is the alt. And it takes longer in cold weather because it takes longer for the alt to warm up.
Do you know someone with a Disco and you can switch with their alt to confirm that it will or will not still act up with a known good alt?
Otherwise these guys have used ones for $75.
http://www.autosportsunlimited.com/index.html
#3
01-02-2008, 07:45 AM
Administrator
#4
01-02-2008, 10:07 AM
#5
01-05-2008, 11:37 AM
Mudding
#6
01-05-2008, 01:03 PM
RE: Charging Problem - need help from the proz
Disco 2,
Yeah we have shops here, and one is really cooperative with working with guys like me thatprefer to do it myself, the other one isn't. I can't see paying a shop to do something anybody with average mechanical skills could do in about 30-50 minutes. To me, it's a challenge, fun, and ya can save abunch of money over getting a rebuild. Plus, like I said, I wanted to keep it original.Shinnynew plating isn'tas important to me as theLand Rover sticker on it.There aren't hardly any parts to an alternator.With a Magnetti Marelli Alt, all the main wear items are on the back of the alternator, easily accessible and ya don't need to mess with the bearings to change any of this stuff. It's sooo easy, in fact, ya could change the brushes/regulator right on the vehicle if ya wanted.
On a high mile vehicle8times out of 10 the problem is worn brushes. Universal brushes are only about $ .50 a set. If ya let them go too long they wear out, arc to thecommutator and wear the contact surface on the shaft. That's when most people have alternator problems and get a rebuild. If they would have serviced it eariler, a couple bucks would have saved them $300. This summer I replaced the brushed on my Caddy alternator (230k mi) and our Jeep G/C (190k mi). Brushes on both were almost worn out.
Other problems could be a failed voltage regulator or a bad diode. In my case, the Autozone on-vehicle test indicated it was a bad diode. For this alternator the diodes are part of a rectifier assembly and becuase L/R is not a common application, vs a Ford/GM/Toyota, I had to get them from my alternator shop. That cost me more than online sources or catalog. I think it was like $40. While I was in there, I also replaced the regulator/brushes assembly (they come as one) with OME and that was about $40. Ultimately I didn't need to as you will later find out, but my thought was to replace the main wear items while I was in there. Putting these on the alternator took maybe 1/2 hr. The bearings look/felt good and I didn't replace them. Sometimes I do replace the bearings, but usually not. Bearing failure isn't very common (although it does happen), and usually the altwill whirl loudly for quite a while before it siezes up and causes other damage. I've run a lot of vehicles well over 200k and never have I had an alternator bearing fail. If ya hear them whirl ya can replace for a couple bucks before it leads to a $300 repair. Apparently a lot of shops and rebuild outfits also repack and reuse the bearings. I also ohmed out the field and other coils and they checked out Ok.
After all this, the alternator acted the same as before the work I did. I had the rebuilt alternator tested a couple times and it tested good. Ultimately the problem turned out to be that the previous owner (or mechanic) put the serpentine belt on incorrectly and there wasn't enough belt contact area around the alternator pulley. So, it would slip when under higher amp draw. I posted more about this in another post. My bad, the Autozone test sent me down a path of looking for an electrical problem. Usually I'm pretty good about looking at the problem from a more global perspective, but did not do so this time. Just goes to show that high tech tests are no substitue fundamental troubleshooting. Also, my L/R does not have a belt routing sticker or diagram under the hood or in the owners manual, to refer to. First time in all my years I ever had a belt installed incorrectly. It works great now.
Yeah we have shops here, and one is really cooperative with working with guys like me thatprefer to do it myself, the other one isn't. I can't see paying a shop to do something anybody with average mechanical skills could do in about 30-50 minutes. To me, it's a challenge, fun, and ya can save abunch of money over getting a rebuild. Plus, like I said, I wanted to keep it original.Shinnynew plating isn'tas important to me as theLand Rover sticker on it.There aren't hardly any parts to an alternator.With a Magnetti Marelli Alt, all the main wear items are on the back of the alternator, easily accessible and ya don't need to mess with the bearings to change any of this stuff. It's sooo easy, in fact, ya could change the brushes/regulator right on the vehicle if ya wanted.
On a high mile vehicle8times out of 10 the problem is worn brushes. Universal brushes are only about $ .50 a set. If ya let them go too long they wear out, arc to thecommutator and wear the contact surface on the shaft. That's when most people have alternator problems and get a rebuild. If they would have serviced it eariler, a couple bucks would have saved them $300. This summer I replaced the brushed on my Caddy alternator (230k mi) and our Jeep G/C (190k mi). Brushes on both were almost worn out.
Other problems could be a failed voltage regulator or a bad diode. In my case, the Autozone on-vehicle test indicated it was a bad diode. For this alternator the diodes are part of a rectifier assembly and becuase L/R is not a common application, vs a Ford/GM/Toyota, I had to get them from my alternator shop. That cost me more than online sources or catalog. I think it was like $40. While I was in there, I also replaced the regulator/brushes assembly (they come as one) with OME and that was about $40. Ultimately I didn't need to as you will later find out, but my thought was to replace the main wear items while I was in there. Putting these on the alternator took maybe 1/2 hr. The bearings look/felt good and I didn't replace them. Sometimes I do replace the bearings, but usually not. Bearing failure isn't very common (although it does happen), and usually the altwill whirl loudly for quite a while before it siezes up and causes other damage. I've run a lot of vehicles well over 200k and never have I had an alternator bearing fail. If ya hear them whirl ya can replace for a couple bucks before it leads to a $300 repair. Apparently a lot of shops and rebuild outfits also repack and reuse the bearings. I also ohmed out the field and other coils and they checked out Ok.
After all this, the alternator acted the same as before the work I did. I had the rebuilt alternator tested a couple times and it tested good. Ultimately the problem turned out to be that the previous owner (or mechanic) put the serpentine belt on incorrectly and there wasn't enough belt contact area around the alternator pulley. So, it would slip when under higher amp draw. I posted more about this in another post. My bad, the Autozone test sent me down a path of looking for an electrical problem. Usually I'm pretty good about looking at the problem from a more global perspective, but did not do so this time. Just goes to show that high tech tests are no substitue fundamental troubleshooting. Also, my L/R does not have a belt routing sticker or diagram under the hood or in the owners manual, to refer to. First time in all my years I ever had a belt installed incorrectly. It works great now.
#7
01-05-2008, 01:16 PM
Mudding
RE: Charging Problem - need help from the proz
Thanks Mark for the note on your belt. Since I have put 35,000 miles on my truck over the two years I have owned, I don't think I have the same problem (at least with proper belt installation). I did check it for tension and visible wear and all looked okay to me. All ground contacts look good as well so my next move is to take the alternator in for testing. I'm a little leary of driving it much as roadside failure in the weather I have going on now is something I'd rather avoid, plus potentially draining a new battery in the process. Also much thanks on the rebuilding info you went through - something I have yet to attempt myself. Disco Mike's advice on buying a replacement with a lifetime guarantee is hard to ignore!
#8
01-05-2008, 01:23 PM
RE: Charging Problem - need help from the proz
Disco 2, what issues are you having? Describe, maybe I can offer suggestions.
BTW, alternators/starters are not rocket science. I've rebuilt many and never had one NOT work. This was the only one I had problems with and ultimately it turned out to work just fine, the problem was elsewhere.
BTW, alternators/starters are not rocket science. I've rebuilt many and never had one NOT work. This was the only one I had problems with and ultimately it turned out to work just fine, the problem was elsewhere.
#9
01-05-2008, 01:35 PM
Mudding
RE: Charging Problem - need help from the proz
My battery went dead on a 7 degree day this week, so I replaced it, checked the alt for positive volt charging, and the battery light still stays on (covered in another post "battery liht won't go out"). Everything else seems okay...all gauges, tach, climate control etc. work properly - the battery warning light remains on.
#10
01-05-2008, 01:42 PM