rurouni2071

when I unplug my battery my car shuts down.. or will run for a few minutes then turn off..?
re ran a ground to my neg cable , ran a secondary wire from pos to my alt.. also the s5 alt test like brand new
anone know what else to check?

dizflyaznboi

the alternator is bad, or you have it hooked up incorrectly. Even if you take it to autozone and it test good it still can be bad, becasue the way they test it on the machine the bearings sit differently. This is true for starters, but i dont know about alternators, just trying to give you some options.

rurouni2071

when I start up the car it runs 14.5 v for a few minutes.. the it kicks down to 11.5 I cant seem to figure out why..

my fan clutch bearing is also going .. says chrysler anyways.. would that put drag on my alt belt maybe..

I am going to hook up a S4 alt I have and see if it'll do the same

RETed

I have never gotten an FC to run with the alternator unhooked.
I won't even attempt to try and explain why.
Maybe one of the electrical gurus could explain?


-Ted

R_PROWESS

iTrader: (3)

thats strange after my rebuild i drove my s4 around the block with the alt unhooked, started it with a charger

j9fd3s

iTrader: (3)

its some sort of shadetree way to test the alternator, its not really a very valid test, as its really hard on the alternator. at least thats what they said in school

lax-rotor

iTrader: (1)

How many amps is your alt pushing through? Depending on the amprage needed for the engine and different components you might not have enough. Check that. Also if the fan is to blame in the slow down of the alternator then that would also explain a drop in both voltage and amprage. Also make sure that it's an electrical problem and not lets say a bad sensor. Use a multimeter to test for opens and shorts anywhere along the way to the alt.

rurouni2071

how would one test for shorts in the charging system? I just put in my S4 alt and its putting out 12.7 - 13.5 volts , and it appears to be steady

now I know there is a million threads on putting in a s5 alt , but I want to double check .. everything on mine was set up the same as the s4 , just a plug swap , is that proper?

Black Knight RX7 FC3S

iTrader: (7)

you can try doing a load test with the car on.
Get a battery/alternator load tester and when the load is activated, if your car shutsoff, your alternator is not producing a stable charge.

HAILERS

http://www.troubleshooters.com/dont_...ct_battery.htm

On the series four alt, have the key to ON and backprobe the White/Black wire and you should see aproxx 3vdc. Start the engine and now you should see approx 14vdc at the White/Black wire if you backprobe it.

That's out of the FSM to the best of my memory. Where's Wayne when you need him?

Here's an outline on how alternators work: https://www.rx7club.com/forum/showth...318post6027318

That's why we invented Google. To search for stuff we know not about.

X-JaVeN-X

Didn't want to make a new thread when this one would work....I've recently ran into what I suspect to be a battery/alt problem. My car isn't being driven now...so I start it every week or so and let it warm upand drive it around the block, and then park it again. I noticed during the last 3 or 4 times or doing this...that when I started the car, it seemed to be a weaker battery each time...well the last time I went to start the car...it was completely dead. I jumped the car, and it started up. I let it run for 10 minutes or so...long enough to warm up...I couldn't disconnect the cables right after jumping it, because my bac is off the car, and it won't idle until it's warmed up sufficiently.

Anyway, after it warmed up and it was idling on it's own (about 10 minutes), I got out and unhooked the cables from the rx7's battery...immediately the fan shut off, and the car promptly died. I've never had this happen...normally, the car will keep running, and that was my plan, to let it charge. So, does this sound like an alt problem, or a battery problem?

Hailers, you say to probe the black/white wire for proper voltages. Can I do this with the car jumped, or do I need to put a good battery in the 7, and then test it?

Where the car was getting weaker with each start over the past month...my first thought was , the alternator wasn't performing sufficiently, and thus the battery was slowly being drained each time I started the car. What should I check first?

rurouni2071

well I got my S5 alt bench tested again and it checked out alright.. again so I put it back in and it still messes up , it still doesnt power the car ... it idles put when I rev it hesitates and lurches then I hooked my jumper battery up as well and it runs smoothly till that one runs down

when off the battery keeps even , with the ignition on it drains steadily and with the car running it varies up and down , but not enough to keep the car running well long

I tried unplugging the E-fan but that didnt do much

I'm guessing that either there is a short after the ignition in the circuit , or maybe the regulator in the alt is shot , does that sound reasonable ? what do you guys think

I'll check the fsm to see if there is a way to test the regulator on the regulator

btw: does anyone know what they check for when bench testing ? would that show a shot reg?

Icemark

Sounds like the alt is wired wrong, not a short (why does everyone think the have a short when they have electrical problems? Do you guys really have no clue about electrical systems at all?)

Is this the correct series alt for the correct series harness or a different series alt than car??? From your earlier posts it sounds like you just put a S5 alt into a S4 car, which would not work. It would be wired backwards and incorrect. Just like a FD alt, the ref and run wires are not wired like a S4.

That has been covered dozens of time here! Hell there are even pictures that have been posted on that.

And what is the voltage when the car is running??? It should be above 13.5 volts, and at 14.4 volts.

Sideways7

iTrader: (7)

Shorts tend to blow fuses...

Icemark

and melt wires... and cause fires.

rurouni2071

okay , the car was like this when I bought it , it has a s5 alt in an s4 car , I dont know how it was wired but it looks like someome just chopped the plug and hooked it up , I'll check the colors of the wires and where they go to

and its fluctating but mostly less than 12.5

Sideways7

iTrader: (7)

I think Icemark nailed it on the head in his last post.

Icemark

I can't believe that this is on the 2nd page...

Your ALT IS WIRED WRONG. Micky Mouse put the alt in, and wired a S5 alt like it was a S4.

it is NOT A SHORT

it is NOT A BAD ALT (unless it was blown up by being wired wrong or by you disconnecting the battery while the car was running... BTW that is a good way to smoke the whole electrical system).

Reverse the two small leads. See if it runs right.

rurouni2071

Okay ,

tomorrow morning I'm going to go and reverse the leads , I'll tell you exactly what i see
I thank you for pointing a kid like me in the right direction and I hope you'll give me some more help if this doesnt solve the problem

Icemark

If reversing the leads works and you haven't blown any internal diodes then you can just leave it. If you have blown the internal diodes then you will have to cut the black/white and run the alt side of that to the battery positive with a 5 amp fuse.

rurouni2071

I wonder what it'll do if the diodes are blown .. fluctuate?

I really do appreciate you helping me , I would be so lost by myself

Icemark

If the input diode is blown (most common when wired wrong) you will have current draw issues when the ignition is turned off.

rurouni2071

alright it runs better with the black/white wire running to the L terminal on the alt , but still is having problems

I put a dmm between my battery ground and the neg post and there was a voltage draw... I just picked up a 5 amp fuse and holder

so correct me if I'm wrong..
from the" L" terminal I am going to run a wire with a 5 amp fuse to the battery ,
then from the "S" terminal will be the white/black wire

Icemark

Huh??? How did you wire the DMM between the battery ground and the battery neg post and get voltage draw???

Do you mean amperage draw?

rurouni2071

sorry battery neg cable and battery neg post , and yeah it would have been amperage , it was on the 12v load setting