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#1
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Troubleshooting Truck electrical
Monday night I went to start the truck, and was greeted with a run down battery. Not enough juice left to crank it fast enough to start.
Checked out electrical system, and figured out there was no output from alternator. Bought a new alternator, but before I changed out the whole thing I decided to try just the voltage reg. And brushes from the rebuilt alternator. Sure enough it works now, battery charges, back to normal But: charge voltage is 13 at idle and 13.5 with engine revved up high. It's within spec but seems to me kind of low, and I am at a loss as to why. I would much prefer to see 13.8 - 14.5 with engine revving. I am thinking for next steps: check battery terminal of alternator with scope to verify if I have any bad rectifiers Check charge current at idle to verify if I have any parasitic loads Unfortunately regulators for this alternator are pricey so I can't easily swap in a new one just for the sake of testing. Truck is an 86 Toyota pickup, with 2.4 Diesel engine. |
#2
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Why not just install the rebuilt alternator you already bought?
Depending on the year the charging voltage may be controlled by the PCM. It may be keeping the voltage low so the amperage doesn't get too high pushing against a low battery.. |
#3
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The truck is very simple, there's no computer or external electronics, the regulator is just a little steel can which Toyota refers to as an "IC Regulator" and is attached to the brush holder under a little metal cover. |
#4
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Thanks Eric - new alternator gives 14.1 V at idle and 14.4 revved up... All seems normal now. It seems odd to me that the olds alternator and old regulator both went bad at once, but it's nice to have the truck back to normal.
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#5
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I don't know why Toyota doesn't build a truck with a small diesel. They built one of the best. If you don't believe it, talk to the people in Cuba. |
Audiokarma |
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I know what you're saying! It was actually a trip to Cuba that had me looking for a Toyota diesel in the first place. I will keep it going as long as possible, this is for sure, there's no real modern equivalent. |
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The next year, all of those issues were corrected, but the sales wouldn't support, continuing the sales in the US. |
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charging system problems, you ended up changing all three to finally get a few years peace out of the system..... Battery, Alt, and regulator. You couldn't use yer brain, or a meter to fix it, you just had to replace it all, or you would be replacing each part over and over...... 1972 - 86 If the battery was 2 year old or less it usually was ok. Our Honda's are much better, and also odd in that we have 6 honda's in the family. 1986 - 1996, Each Alt. went at around 170K miles, then with 300K to 420K on those cars presently, the second Alt. in each car, A Honda Factory rebuild has not had any troubles.... .
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Yes you can call me "Squirrel boy" Last edited by Username1; 10-03-2015 at 02:46 PM. |
#9
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I have owned my repair shop for 36 years now and I only use BOSCH alternators and starter even in us cars no Auto Zone junk . Bosch top quality no come backs.
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#10
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he use to have to replace it every year or two. I asked him, so where is the bargain in that ? AZ is a mindset kinda place. The labor to keep replacing cheap guaranteed forever junk is too expensive.... .
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Yes you can call me "Squirrel boy" |
Audiokarma |
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#12
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With the Toyota it was a matter of what was possible to find - last year the 2.4l diesel was sold was 1986, and with how old cars rust around here the demand for parts has got to be nearly nil. It's still working so the new alternator definitely did the trick!
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#13
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Yes ~ He was one of only one person I know who has ever had a battery explode
in his car from overcharging..... His '86 T-bird, the car he had during his AZ years, whenever the alt. light would come on, once or twice a year, he said "I got 20 seconds to close all the windows, and get parked, then the car's dead in the water..... I told him after watching it for a few years, "Go get all new stuff from the dealer and fix it once, and be done with it" I am pretty much a fan of OE parts, our '79 Mercury (Colony Park ??) LTD wagon had a original new Ford battery from the factory last 10 years...... Amazing ! ! .
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Yes you can call me "Squirrel boy" |
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