well, I changed my water pump. only moved the alternator down to remove the belt. nothing got pinched. didn't mess with any wiring, no coolant on any wiring.

battery won't charge. alternator puts out 13.96 volts while running. my gauge in the cluster usually sits just above 12 when it was running correctly but now it sits just below 14 all the time no matter how long I drive it and I shut off, then go to start and nothing. maybe 2 slow cranks and then dead. I have recently wired up a mercury villager e fan to ignition for now so always on. has that killed my battery? its been fine for 2 weeks driving to work everyday.

Things I have checked:
meter fuse good
battery tested at bond auto, tested good but needs to be charged (obviously)
all connections at bettery look great, no corrosion, took off and put back on terminals. connections are tight.
checked all alternator wiring for kinks/shorts at the alternator but no further. just the area that would be affected by me moving the alternator. its all good and putting out 13.96 ( not great but adequate).
tried disconnecting my e fan completely and running it but results are same. battery is not charging.

it can't be anything "ghosting" power because I can drive it for 30 minutes and shut off and its dead. This coincided with me doing the water pump (just the pump, not the housing). I must have done something but what? is there a relay for the charging circuit or something I am missing? Is it the alternator?

 

Have you tried charging the battery w/a battery charger?

 

^I'm going to but don't have my own charger. I need to borrow one tomorrow hopefully. I push started the car 3 times today and its fine once its started. it just won't charge the battery. This battery has been drained a few times since I've owned it as I have had other issues with my terminal connector cracking and left my parking lights on 2 times (all over the course of 2 years). battery tested good with no dead cells though. I'll update tuesday hopefully after I get it on the charger. I have an aftermarket scotch positive terminal connector that has allen screw slots that hold the positive wiring. I have checked and rechecked the allen screws and wiring and it has good contact there as well.

 

Did you ever test the voltage from the battery while the car was running? The voltage would be about .5 volts less than at the alternator output wire.

 

yes, I see you found my other thread. so alt is at 13.96 and batt is at 12.54 and not charging any more. even though its at 12, it is instantly dead when shut off. maybe the cold cranking amps (and battery) have gone kaput?

 

See your other thread I just posted in

 

https://www.rx7club.com/2nd-generati...1033485/page3/

other thread of mine regarding my cooling problem and how I came to this charging problem.

 

solved, I don't know what it was but see the other thread for all I did and then it worked.

 

pin pointed. its the connector on the back of the alternator (for the L and R terminal wires). the prongs were very rusty/corroded. sanded em down and now she's charging.

 

I'm back. they alternator has been tested off car. puts out 14.5v. I got a new battery but it seems something is draining and it might be due to my 70 amp alternator. Its a little chili and raining so I was running my lights, wipers, rear defrost, and heat blower on high. each of these things made my stock volt gauge go lower. all of them had it sitting right on 12v. At idle though it would drop below a little.

I have my e fan wired up to a single temp probe and relay. so thats not on all the time anymore and the power source is hooked to ignition power. On such a cold day, the fan shouldn't even need to come on as I was only idling maybe 1 minutes max at a time.

the B+ wire is putting out 14v and at least some of it is getting to the battery. I'm wondering if it might have to do with starter wiring at this point.

after driving 6 miles (and not shutting off the car for a while anyway before that), I got home and shut it off. battery (still hooked up) tested 12.46. after I first took it for a drive with new battery it was 12.84 with car off. 12.46 seems a little low to me. I'm going to start pulling fuses checking for a drain. battery has good ground and continuity between b+ and positive.

 

if your voltage at the alternator is 13+ volts and at the battery it is 12.54v then your charge wire is having issues.

disconnect the battery and remove the charge wire off the alternator, check to be sure the armature is tight on the alternator under the black blind cap on the back of the alternator. clean and tighten the charge wire to the alternator. then check and clean both 10mm bolts to the main fuse inside the main fuse block in the engine bay.

last but not least be sure all wires are secure and clean at the battery.

if the battery is charging at 13+ volts and it is still dead when it sits overnight then you have a draw in the system, the usual problem area is aftermarket alarm systems.

 

well I don't have an alarm system and I have checked connections multiple, multiple times so ya, I'm checking for power draws but its not overnight. it loses powere little by little while driving. my e fan is on a relay temp switch now but even with fan off, my charge is diminishing at idle and very low with lights,wipers,blower on. must be a wiring issue. because of the e fan, I'm also going to get my alternator rewound and set for 100 amps. seems easier on a S4 car then getting a different alternator. thanks for the help.

 

sounds like you're putting a bandaid on it by rewinding the alternator, which usually results in less amps at idle versus while moving. i would be looking at the charge wire off the alternator, if it's over 1 volt discrepancy then you know that is a problem, it should be about .1 volt.

if the output at the alternator is over 13v then it is doing it's job just fine and the problem still needs to be found and addressed.

 

Dude, just run a new battery charge wire, It's easy.

Needed...

1) a 4 feet of 8 or 4ga wire. Yes, a little long, but it gives you options for routing.
2) high temperature wire loom, don't run that **** bare!
3) 10 minutes.

That should fix your issue. Yes, it won't be fused, but many modern production cars i work on today do not have a fused charge wire. If you want to fuse it, I can go over options with you as well, but it really isn't needed.

 

Sorry, you mis understood. I am going to be running new wire on that charging circuit. I have put an e fan in recently as a step to solve an over heating problem (was thermostat, had a stant :/ ) and had it hooked to ignition. I have wired it correctly through relay temp switch now but there is a large drain when its on so that was the reason I am also rewinding the alternator. I was unaware it would affect my idle amps, would it be better to use the FD alternator? I was rewinding to save some money for myself and it would be an easier install.

also, I have a spare fuse slot in my engine bay box so I could run my charging wire there. How complicated is it to completely remove the stock charging circuit wiring and replace it and put back into the stock loom (run a new loom of course)? does it go all the way through the starter or is it direct to battery? I haven't opened the loom and it disappears into it so not sure on how its routed. I'm not super successful with traditional wiring diagrams either but I could figure it out.

 

it depends on the winding process, you should ask the shop that is going to be rewinding as for what to expect from their service.

 

it takes like 10 seconds to voltage drop test any load. VD testing will tell you everything you need to know to find the problem

 

Numbers

Car off, battery read 12.31 at posts (still connected). night before it was 12.45 when shut down. It was a little cold last night but will check for ghost power.

Car on, during warm up period (my car stays at 1000-1100 after first drop from 2000 rpm for a while before dropping to idle). This is with my e fan off and right after start up.
battery: 13.58v
neg post to alternator housing: 0.00-0.01
Pos to B+: 0.61-0.64 (read this is not supposed to be over .2v)
neg to B+: 14.35

Car on, all acceries on (wipers, lights, blower full, rear defrost, normal deck)
battery: 13.07 but drops .01v every 3 seconds or so. seems to level off around 12.66 at idle (750 rpm)
neg to alt housing: 0.34-0.35
Pos to B+: 0.77-0.83
neg to B+: 13.61-13.68

at idle of 750rpm, alt is putting out 13.41, batt is at 12.96 area with acc off. acc on at idle, alt puts out 13.02-13.50 sparatic. it seems that when I turn accesories on, my ground goes up to 0.35 max but is all over the place between 0.00 and 0.35. this happens no matter which accesories, I tried each by themselves.

Do you think grounding my e fan to a chassis ground will help anything? it is on neg batt right now but it is a ground so why would that matter? I have no corrosion at terminals, never have. another note, with all my acc on, if I hit the brake pedal at idle, voltage/alt drops right at the 12 line. below it if I have been driving with all accesories on for a while. let go of brakes and it jumps back up. almost like its only running off the alternator.

I read a trick to see if batery cables are good. turn headlights on and start car. if the lights stay bright then they are good. how good of a test is that because my lights dim a bit and whenever I hit brakes all dash lights/headlights dim at night. its noticable.

all my connections are good, belt is tight not overly or less so. new battery, alt test at 14.5v off car. I suppose I will clean up all my grounds again (have before) and run new positive wiring. Sounds like wiring to you guys too?

 

stop running around in circles, a .7v drop across the charge cable is too high. that is probably a net loss of 20-30 amps from the alternator.

 

double checking. I don't know **** about wiring or charging circuits. My first issue with them. So Going to run the new wires b+ to starter, to battery. I'll try cleaning and putting dielectric grease or whatever on the grounds before replacing those completely. I didn't grease them last time, just cleaned. thanks for the help. I'll update when I get it done, its raining and I have no garage so might be a week or so.

 

you're missing the problem again.

the problem isn't the battery wire to the starter, it is the thick alternator wire to the 80a fuse in the fuse box, or the wire off the other side of that fuse to the battery or both. high resistance in that circuit is eating up voltage/amps.

 

oh, I thought that the b+ went to the starter first and then to that fuse. I'll look at the diagram. I read something and must have misunderstood how its wired. regardless, I have been having minor starter issues as well so I'm doing the whole thing. all to the starter, all to the battery pre and post fuse. I'm not messing around with the fix, going ALL new wire for the entire circuit back to the starter and battery. That should solve everything in one fell swoop. Thanks for correcting me, I know I'm a noob at electrical.

 

The positive wire from the battery goes to two places. The thicker of the two runs directly to the starter while the thinner wire runs to the engine fuse box. The thinner wire's voltage passes through the Main fuse and runs to the Ignition Switch. The alternator output wire splices into this thinner wire.

 

thank you. hmm, then I suppose I will end up replacing the wire all the way to the switch. no point replacing it only to where the alt splices in. If I'm going through the trouble I might as well.

 

You don't need to replace it all the way to the Ignition Switch as it wouldn't achieve much. Running the wire straight to the battery would be a better alternative.