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Hello new to Rx7club. I'm having problems with my 87 fc it's a glx with a t2 swap with adaptronic. Im have a confusing electrical problem with my car. It started while normal driving yesterday and all of a sudden the wipers started going crazy, back and forth really fast . And then I pulled over and it seemed the slower I drove the wiper speed slows down. So I unplugged the wiper motor to get it home. and when I pulled off the car shut down about 20ft down the road and costed to a stop. I found that the main engine 80amp fuse was blown, so I looked around for a short or + cable touching the frame and found a small hot wire touching but did not see any arc strike as it was on a really rusted part. So maybe didn't even cause the issue. But I wrapped that with electric tape and got it out of the way. And replaced the fuse and for some reason the fuel pump then would not turn on threw the relay so in effort to just make it home. I wired the + from Batt directly to the fuel pump bypassing the relay and only then would it turn on.(may have something to do with the wires from the fuel pump relay that are running to the adaptronic ecu. Could someone explain why this is wired like this??)anyway , So I got it started and drove another 50ft before the same 80app fuse was blown again. I don't see any shorts or any visible problem. What could this be?? could this have something to do with the way the alternator is wired in because I have a fd s6 alternator on my s4.? Iv had nothing but electrical problems with this car since I bought it and it's driving me insane. thanks in advance for any helpful response
If so , Is this something I could fix if I took the alt apart? I have a diode kit laying around somewhere. what makes you think this is the problem? any knowledge on the fuel pump relay question? why it's wired to the ecu (aux) or why the fuel pump won't turn on through a relay ?
the fuel pump no I'm not sure, but being as you have a adaptronic, it may be controlling the fuel pump through the software, but I'm not sure because I don't know aftermarket ECUs
you could fix the alternator, they are very easy to take apart and put back together, another thing you could do it bring and get the alternator tested to see if my guess is correct or not, but being as it blew the main fuse, and your wipers were going with the RPMs of the car, that screams alternator to me
Okay so I took the alternator off and something is definitely wrong with it when I turn it by hand it's sounds like his rubbing against something and aluminium shavings come out of the casing.
I tried to take it apart and look inside but this alt does not let you inside of it with ease. so I just ordered another one and will probably have this one rebuilt. but it still doesn't explain why the ecu stopped giving me ground or enough power to the fuel pump relay to turn the pump on. I hope I didn't damage anything everything els ecu related works fine. another thing that went wrong when this all happens was my wide band just stopped turning on & it's getting both power and ground.?? wiper motor does not work either after it went berserk.
yes it does, EVERYTHING is powered by the alternator, when it dies, the battery can only keep everything going for so long, everything in a car is supposed to "normally" have 12v DC, when the alternator dies, and the battery starts getting below 12v, electronics do some WEIRD things because they all try fighting for the voltage
Case in point, when my alternator died, my aftermarket radio shut off randomly, then came back on, then went back out, thats what told me my alternator was dead, and it was
Get your new alternator in, and to be on the safe side, get your battery checked if its on the older side, everything scavenging the battery can damage it
Yea now that you say that, that could be the issue with the ecu no supplying enough power to relay. idk but I guess I'll find out when I change the alternator.
when I hooked my jeep up to it to start it, my jeeps voltage was 14 but for some reason my Battery voltage stayed the same around 11.2 with the jumper cables still connected properly, as if my car was not allowing the charge from my jeeps alternator to go into my battery into the car itself and the battery is only a week old & the ground and positive cable have tested good for continuity. How could the alternator being messed up cause this? also when I disconnected the jump cables the voltage slowly dropped to 9.8 volts and my car some how stayed running and did not stall out?? which is very strange because about a week ago before I replace the battery. if the voltage we're to drop below 11v the car would shut down everytime
I know there are a few forums on swaping the s6 alt into the s4 but if someone has a correct proven way to do this, could you please help reassure that I'm doing it the right way before I get my new alternator.
Ok so my new alternator came in and I installed it & it does seem to have fixed the short problem I think only because the main fuse hasn't blown yet. but at idle I'm still only getting about 12.5 -13 volts and if I rev the car up the voltage will go up to 14.5 but as soon as it goes back to idle it drops to 13 again.
if I put the volt meter on the (b+) post on alternator it's gives me more voltage than when I check the battery.. e.g if the alt is pushing 13.80 volts the battery only only reads about 12.60 volt for some reason ? what could be causing this? and it's like the car only starts when it wants. once I get it started it will run great (besides it not charging enough) but if I turn it off and try to start it again it just keeps cranking and will randomly eventually start
I understand that there are plenty of threads that cover the alt swap because iv read all of them but none have the problem I'm having. So please someone help me out here.... Im almost positive I have the alt wired correctly. but my idiot light cluster does not light up at all any more. so I have a the small (w/b) (L) wire, wired into a switched ignition and inline light. because my cluster lights do not work for some reason. this is what I used to wire in the s6 alt
when the fuse blew the First time the wiper motor, idiot lights, wide band o2 & fuel pump all stopped working at the same time and still do not work im thinking maybe the problem has something to do with that or at least isn't helping and I don't even have an idea how to fix that at this point being that all the fuses are good and I can't find any shorts.the only way I can get the fuel pump to work is to wire in separate ground to relay
also IDK if I'm replying to the whole thread or just a individuals comment so let me know I new at this.
Last edited by Travis Duncan; 04-01-17 at 08:28 PM.
I remember vaguely that there is (supposedly) a way to wire the alternator incorrectly such that it would work, but will always provide low output. I don't remember the specifics, but it is possible that you did that. The following link has a wiring diagram for the s6 alternator in an s4 car (although I've never tried it as I am in the process of converting to a Taurus 130 Amp alternator)
okay iv got the alternator wired correctly iv checked every forum i could find on the subject and im 99.8% sure that it is correct also the alternator is putting out 14.5 volts at the pos post on the alternator.
The problem i am having now is that something is preventing the battery from receiving 14.5 volts. my battery will only show 13.8 at idle while at the same time the alternator is putting out 14.5 volts. iv checked with multiple multi-meters. the wire coming from the post on alt is getting warm.
could this be that i need to get a bigger lead from the alt to the main fuse? because while the alternator is putting out 14.5 volts when i check the other end of the wire coming from the alt before the fuse (about 12 inches away from the alt post) it only reads 13.8 the same as the rest of the system. this makes me think maybe if i upgrade the wire it will help, i dont know. the alternator is a 130amp and iv upgraded the old 80amp fuse to a 120amp
i adjusted the tps on the adaptronic software and fixed the no start issue but i still have not figured out why the idiot light cluster is not working. only a few of the bulbs are blown and the CPU alt relay does click open when i test it.
& im guessing that i fried the wideband because it too still does not come on. which is a shame because they are pretty expensive.
if you got a 130 amp alternator then yes, run an upgraded wire. You already gave away your first clue to that with 14.5V at the alternator, but 13.8 at the other end of the wire, means there is resistance and thats why its getting warm
03-28-17, 07:27 AM
