Ok so my alt fuse says on the fuse box cover 1.25B. It has a 60 amp fuse in the place. I'm reading on tsrm that there is suppose to be 100 amp fuse. Which one do I get 60 amp fuse or 100 amp fuse? Or am I suppose to have a fusible link?
Help! Supra doesn't run right
- Thread starter Abe's 1987
- Start date
I've read someone talked to a electrical engineer which told this guy that 1.25b converts to 80 amps.
I believe that's your expertise Mr. 3p141592654. What's your take on that?
I believe that's your expertise Mr. 3p141592654. What's your take on that?
Have you followed the TSRM for the charging system yet?
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=CH&P=2
Does your dash battery light work? (Charge warning light)
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=42
Diagram shows the 2 fuses and 2 fusable links required for alternator output to function properly.
Key on, engine off it is illuminated?
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=CH&P=2
Does your dash battery light work? (Charge warning light)
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=42
Diagram shows the 2 fuses and 2 fusable links required for alternator output to function properly.
Key on, engine off it is illuminated?
Took the alternator to autozone, O'Reillys, and advance auto part today to have it tested. Alternator tested good at autozone and O'Reilly and the guy at advance could not figure out how to test it right so it kept testing bad.
I will start with tsrm tomorrow to figure out my issue.
My 87 turbo uses a 80 amp alternator. The difference is the non turbo Supra uses a slightly smaller 70 amp alternator. Best to go with the highest output one you can get.
I heard of people running the MR2 alternator which is rated at 100 Amps but you need the pulley from a 89+ alternator.
You've got the alternator out, so the tests are simple.
With the battery connected do you have 12 V at the big alternator wire. If the answer is no, then work you way back and find the problem. The obvious first thing to check is the Alternator fusible link. Hacked wiring would be the second most likely cause. Its a pretty short connection from the alternator to the fuse box under the hood. The car would not run if the battery FL was bad.
Be careful with that loose alternator wire if the battery is connected. If it touches a ground you will at the very least blow a FL.
As far as fusible links go, they are typically sized 4 gauges smaller than the protected current. 1.25mm is roughly 16 AWG, which is rated about 20A, so that FL would protect an 80A circuit. But FLs use special high temp insulators so don' try to make your own. Go buy it from Toyota if it turns out you need it.
With the battery connected do you have 12 V at the big alternator wire. If the answer is no, then work you way back and find the problem. The obvious first thing to check is the Alternator fusible link. Hacked wiring would be the second most likely cause. Its a pretty short connection from the alternator to the fuse box under the hood. The car would not run if the battery FL was bad.
Be careful with that loose alternator wire if the battery is connected. If it touches a ground you will at the very least blow a FL.
As far as fusible links go, they are typically sized 4 gauges smaller than the protected current. 1.25mm is roughly 16 AWG, which is rated about 20A, so that FL would protect an 80A circuit. But FLs use special high temp insulators so don' try to make your own. Go buy it from Toyota if it turns out you need it.
Ok so dropped the alternator back in with a 80 amp fuse. Battery warning light came on with key on then went off with car started. Tested volts to battery. Was getting 14.4 volts. Tested volts to fuel pump 8.9 at idle and 11.5 at 2800 rpms but wouldn't rev past 2800 rpm. Turned car off. Volts slowly went down to 12.7 volts.
Put key back to on position again and battery warning light did not light up. Turned car back on and volts at battery were 12.4 volts. Turned car off and tested volts to black wire of alternator and was at 12.67 volts. Tried unplugging and plugging alternator and battery to see if it will start charging again but no luck. Tested all wires to alternator and all tested good.
Conclusion bad alternator or bad alternator connector. But confused as autozone and O'Reilly tested it good yet advance tested it bad.
Also with alternator working car only revved to about 2800 rpms but with the alternator not working it revved up to 4000 rpms.
Side note; never put hands near moving parts. Tore up the tip of my finger on the cps. 1 and a half hours later it still burns.
Put key back to on position again and battery warning light did not light up. Turned car back on and volts at battery were 12.4 volts. Turned car off and tested volts to black wire of alternator and was at 12.67 volts. Tried unplugging and plugging alternator and battery to see if it will start charging again but no luck. Tested all wires to alternator and all tested good.
Conclusion bad alternator or bad alternator connector. But confused as autozone and O'Reilly tested it good yet advance tested it bad.
Also with alternator working car only revved to about 2800 rpms but with the alternator not working it revved up to 4000 rpms.
Side note; never put hands near moving parts. Tore up the tip of my finger on the cps. 1 and a half hours later it still burns.
Unless I'm missing it I didn't see anything on the 3 pin connector testing on the tsrm.
You can use the wiring diagram to meter out the Alternator wiring.
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=042
Are you running a 7M or 1J/2J alternator?
Ignition on, engine not started, battery light on. Engine started, battery light off. That is the basic test of the three pin warning light circuit and its odd that it worked fine once, then not the second time when charging was an issue.
One point I'll make is that my alternator when the brushes wore out became intermittent. It would snap between working and not working. With the car idling suddenly it would start charging, and then stop after a while, no rhyme or reason to it.
Its easy to remove the brushes and check their length.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=CH&P=7
Also, with low voltage the ECU will lengthen the injector pulse widths. This could play into your fuel issue and explain why the car ran differently with and without the charging working.
One point I'll make is that my alternator when the brushes wore out became intermittent. It would snap between working and not working. With the car idling suddenly it would start charging, and then stop after a while, no rhyme or reason to it.
Its easy to remove the brushes and check their length.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=CH&P=7
Also, with low voltage the ECU will lengthen the injector pulse widths. This could play into your fuel issue and explain why the car ran differently with and without the charging working.
I've now dealt with that parts store alternator test circus with 4 different vehicles and concluded that the test is only a small part of a good diagnostic. I got both good and bad test results with multiple vehicles, back to back. I think their test is simplistic enough and of short enough duration that you can have a failed alternator pass or fail. I think I also had a good alternator fail once with my Land Cruiser. I was on a cross country road trip and couldn't replace it myself (pain in the ass job compared to a mk3) and had my pregnant wife with me. I paid a very painful $500 for Sears to replace the alternator only to still have the temper-mental charging issue.
Checking the brushes and bench testing yourself is a good way to go. Picking up a Denso alternator from Rock Auto is probably a relatively cheap peace of mind if you're unsure of the current unit's health or how to rebuild it.
That is true because I just had the battery tested with their tester three times and tested good all three times. They put it on a charger and found out it was bad. So hard to trust their testers. I guess it would be more piece of mind to just drop in a new alternator atm as all my wires are looking and testing good. To my memory I was getting the battery warning light on with key on and off with car started but wasn't getting the charge. But has to wait as my camaro needs new fuel line and bmw needs new shifter assembly. Benefits of owning three cars cost a soul to maintain all three. And of course my dd bmw comes first as it is my family car.
So rebuilding it would be cheaper then buying new one? Where do I find parts for the rebuild? Is there places I can take it in for rebuilding it?