fc na a few questions and issues
03-04-11, 02:50 AM
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turbo II swap coming soon
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fc na a few questions and issues
ok so ive read thread after thread and im still having a hard time with some of these even though i know these subjects have been covered
1: i just installed an fd alt in my 86 na and i cut the plug off my harness and wired in an fd plug
the alt was running 15.2 volts at first but now is down to about 14.5(multimeter) or so and is staying steadily there. ive been keeping an eye on it. ive read threads about how your suppose to rewire it but i looked at icemarks wiring diagrams for alts and it appears the way i wired the plug in is correct although other people leave out a wire? anyway the real problem is sometimes when i stop and have the break on it drops down to 12 volts and wont go back up to normal until i start driving? what can cause this? a bad ground? it only happens sometimes. (my old 70a alt did this also but it was shot it would drop down to 11.5 sometimes with the break on when it got around 0 degrees) its a little below freezing most of the time around here now as its winter
oh and i bought a 100a fuse to replace the 80 but i havent done that yet? just wanted to make sure that was important to do to handle the alt? i didnt know if anything else had to be modified for that big of a fuse??
2: the car is beginning to run hot. again ive read multiple threads on this. it just started after a four hour drive on the freeway with a half hour break in between. it was fine until i got off the freeway and then my heat gauge started rising and stopped barely above half and was there until i got home. it didnt go any higher. it usually runs a quarter to a third up the guage. now at idle it sits there and when i drive its a little under half? the coolant is full. there is no oil in it. my guess is maybe the rad. im doing a t2 swap eventually and have a t2 radiator. will that be ok to swap in on my na? just making sure it will before i try. i replaced the thermostat a few months ago. there are no leaks and im not losing coolant.
3: weird issue that also just started two days ago about the same time the engine heat started rising. my oil pressure guage usually reads about 60 at 3k. then all yesterday it would only read about 45-50 at 3k. now today its reading 60 at around 2.2k and an even 30 at idle. and my idle is a steady 750 its bouncing up and down between 700 and 750 its usually completely steady?
does anybody got any ideas to what may be causing these issues. like i said ive read numerous threads but i feel like mine might be tied together?
any help is appreciated. thanks guys
oh i installed a k&n cold air intake 57-5005 about a week ago to accommodate my vented hood and before 2 days ago it was running a little cooler. also
1: i just installed an fd alt in my 86 na and i cut the plug off my harness and wired in an fd plug
the alt was running 15.2 volts at first but now is down to about 14.5(multimeter) or so and is staying steadily there. ive been keeping an eye on it. ive read threads about how your suppose to rewire it but i looked at icemarks wiring diagrams for alts and it appears the way i wired the plug in is correct although other people leave out a wire? anyway the real problem is sometimes when i stop and have the break on it drops down to 12 volts and wont go back up to normal until i start driving? what can cause this? a bad ground? it only happens sometimes. (my old 70a alt did this also but it was shot it would drop down to 11.5 sometimes with the break on when it got around 0 degrees) its a little below freezing most of the time around here now as its winter
oh and i bought a 100a fuse to replace the 80 but i havent done that yet? just wanted to make sure that was important to do to handle the alt? i didnt know if anything else had to be modified for that big of a fuse??
2: the car is beginning to run hot. again ive read multiple threads on this. it just started after a four hour drive on the freeway with a half hour break in between. it was fine until i got off the freeway and then my heat gauge started rising and stopped barely above half and was there until i got home. it didnt go any higher. it usually runs a quarter to a third up the guage. now at idle it sits there and when i drive its a little under half? the coolant is full. there is no oil in it. my guess is maybe the rad. im doing a t2 swap eventually and have a t2 radiator. will that be ok to swap in on my na? just making sure it will before i try. i replaced the thermostat a few months ago. there are no leaks and im not losing coolant.
3: weird issue that also just started two days ago about the same time the engine heat started rising. my oil pressure guage usually reads about 60 at 3k. then all yesterday it would only read about 45-50 at 3k. now today its reading 60 at around 2.2k and an even 30 at idle. and my idle is a steady 750 its bouncing up and down between 700 and 750 its usually completely steady?
does anybody got any ideas to what may be causing these issues. like i said ive read numerous threads but i feel like mine might be tied together?
any help is appreciated. thanks guys
oh i installed a k&n cold air intake 57-5005 about a week ago to accommodate my vented hood and before 2 days ago it was running a little cooler. also
Last edited by Mitchigator; 03-04-11 at 02:53 AM.
03-04-11, 03:20 AM
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turbo II swap coming soon
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I wired the s wire from the fd alt to the ignition wire that went to the r terminal on my s4 alt. Should I rewire the s terminal the the main 80a fuse instead? Isn't that where the b terminal goes also to ground?
03-04-11, 06:55 AM
#3
Rotary Freak
You NEED to use the WHITE/black wire that was in the old series four alt plug.
That's the excitation wire for the alternator.
The S terminal..........I have it running to the engine bay fuse box to where one of the EGI fuses is. Others just run it to the output wire on the alternator.
I had my WHITE/black wire fall off the alt the other day. The alt output was close to fifteen vdc. Not good. So I reconnected the White/Black wire to the alternator.
About alternators and what little I know..................if the excitation wire does not exist, an alternator can still put out. It does this thru self excitatioin due to residual magnatism in the rotor/coils. But this won't happen unless the engnine is rev'd up quite a bit. Then even though now its got allllll excited and is putting out, the output is not regulated hence the fifteen vdc seen with the meter.
Make sure you don't confuse which terminal on the alt is S and which is L. The jack on the alt is *keyed* in the sense that the locking device that holds the elect plug on to the jack is at the top of the jack. So you look at the jack and have the locking device at the top when viewing the jack. Then the S is to your left and L is to your right. Or another way of making sure is .......the S is closer to the output terminal of the alt than the L is.
Some of what I wrote made sense.........I think.
One thing I did when I put a series five alt in the series four car was...........I spliced in a wire to the White/Black wire and put a female terminal on that new wires end. So now even though the White/Black is connected to the alt jack, I now have the ability to read the power on the WHITE/Black with the engine running without backprobing the White/Black at the alternators elect plug. I did this so I would know what's going on. IF the key is put to ON, engine OFF, the white/black should read approx 3vdc (excitation voltage via the CPU alt relay). IF that 3vdc is there I KNOW things are going to work out for me and the car.
White/Black wire on a series four is for more than just turning on the idiot lights. The series five cars have the equiv to a white/black but the color on those series five excapes me right now. Just a color diff.
That's the excitation wire for the alternator.
The S terminal..........I have it running to the engine bay fuse box to where one of the EGI fuses is. Others just run it to the output wire on the alternator.
I had my WHITE/black wire fall off the alt the other day. The alt output was close to fifteen vdc. Not good. So I reconnected the White/Black wire to the alternator.
About alternators and what little I know..................if the excitation wire does not exist, an alternator can still put out. It does this thru self excitatioin due to residual magnatism in the rotor/coils. But this won't happen unless the engnine is rev'd up quite a bit. Then even though now its got allllll excited and is putting out, the output is not regulated hence the fifteen vdc seen with the meter.
Make sure you don't confuse which terminal on the alt is S and which is L. The jack on the alt is *keyed* in the sense that the locking device that holds the elect plug on to the jack is at the top of the jack. So you look at the jack and have the locking device at the top when viewing the jack. Then the S is to your left and L is to your right. Or another way of making sure is .......the S is closer to the output terminal of the alt than the L is.
Some of what I wrote made sense.........I think.
One thing I did when I put a series five alt in the series four car was...........I spliced in a wire to the White/Black wire and put a female terminal on that new wires end. So now even though the White/Black is connected to the alt jack, I now have the ability to read the power on the WHITE/Black with the engine running without backprobing the White/Black at the alternators elect plug. I did this so I would know what's going on. IF the key is put to ON, engine OFF, the white/black should read approx 3vdc (excitation voltage via the CPU alt relay). IF that 3vdc is there I KNOW things are going to work out for me and the car.
White/Black wire on a series four is for more than just turning on the idiot lights. The series five cars have the equiv to a white/black but the color on those series five excapes me right now. Just a color diff.
03-04-11, 07:20 AM
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So Im sorry man I'm lost
so I run the white/black wire from my harness to where on the alt? And I run the s wire to my fuse box? And what do you mean some people wire it to the output wire on the alt? Which wire is that
Ok there's three wires on the alt.
The b wire which hooks to the screw which leaves two more wires. The s and l. Stop me if I'm wrong. So where does the s wire go and where does the l wire go?
Do I use both wires that are from my s4 harness?
so I run the white/black wire from my harness to where on the alt? And I run the s wire to my fuse box? And what do you mean some people wire it to the output wire on the alt? Which wire is that
Ok there's three wires on the alt.
The b wire which hooks to the screw which leaves two more wires. The s and l. Stop me if I'm wrong. So where does the s wire go and where does the l wire go?
Do I use both wires that are from my s4 harness?
03-04-11, 07:29 AM
#7
So Im sorry man I'm lost
so I run the white/black wire from my harness to where on the alt? And I run the s wire to my fuse box? And what do you mean some people wire it to the output wire on the alt? Which wire is that
Ok there's three wires on the alt.
The b wire which hooks to the screw which leaves two more wires. The s and l. Stop me if I'm wrong. So where does the s wire go and where does the l wire go?
Do I use both wires that are from my s4 harness?
so I run the white/black wire from my harness to where on the alt? And I run the s wire to my fuse box? And what do you mean some people wire it to the output wire on the alt? Which wire is that
Ok there's three wires on the alt.
The b wire which hooks to the screw which leaves two more wires. The s and l. Stop me if I'm wrong. So where does the s wire go and where does the l wire go?
Do I use both wires that are from my s4 harness?
Alternator wiring diagrams: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/frequently-asked-questions-2nd-generation-rx-7-faq-fc-494667/
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03-04-11, 07:37 AM
#8
turbo II swap coming soon
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B terminal = output wire. Since B/W wire from alternator needs "constant voltage" rather than "switched voltage" the B/W wire from alternator "can" run to the B terminal or to another constant voltage source such as at the engine fuse box.
Alternator wiring diagrams: https://www.rx7club.com/showthread.php?t=494667
Alternator wiring diagrams: https://www.rx7club.com/showthread.php?t=494667
03-04-11, 07:46 AM
#9
So what you are saying is disconnect the black and white wire from my harness and run the black and white wire from the plug coming off my alt to the b terminal on my alt and it will work? So one wire will be connected to two places on the alternator. That just sounds weird so I am being clear. Or I can run it to the fuse box? The main fuse will work correct? Sorry this must be painful for you guys to explain
03-04-11, 07:51 AM
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turbo II swap coming soon
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Hailers suggested it "could" be run to one of two places such as "either" the B terminal or to another constant voltage source such as the engine fuse box. What is the best fuse to choose from at the engine fuse box depends as most folks wire it to a lower amperage fuse than the Main fuse. As to why, I am not certain.
I'll just run it to the b terminal and simplify things
it's seems the fastest way to do it and I won't have to add wire
I'll just clip the butt connector I used to hook the wire to the harness and put on a connector to go around the b terminal bolt.
As far as the main fuse goes should I switch to the 100a fuse or is it still ok to stay with 80
03-04-11, 04:37 PM
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I got the alt connected properly i figured id give you guys some pics! i had a hard time finding them when i was trying to do this and hopefully this helps someone out.
as far as my other problems any ideas??
will t2 alt work on my na
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