I took the car out for a test drive yesterday. Got about 1 mile down the highway and i notice the gauges start to dim and my headlights were dimming. By the time i got to the next exit, the gauges were completely dark. I pulled over and the car sputtered a few times and the idle got rough and dropped really low. I tapped the gas pedal, it reved a bit and died. I attempted to crank the car and it would not turn over. I had the car towed back home. Today i put a boost box on it and it started right away. I removed the booster box almost immediately. The battery voltage remained at 14v. I let the car idle for half an hour with the headlights, stereo and fan blower motor on attempting to reproduce the problem. The lowest the voltage got was 13v. Took the car for a spin in the subdivision and the voltage never dropped bellow 13.5v. I parked the car and shut it down. Upon restarting it, the idle was a bit higher (not sure if this is related). The voltage read 12v. After a few minutes it was back up at 13.5v.

The car has a FD alternator. I do not think there is anythign wrong with the alternator or else it would have died when i shut off the booster box. I checked the connections between the harness and the alternator and it all looked ok. Is there some control circuit that could be going crazy? The car is running a haltech so the stock computer is not there. Any idea whats going oon?

thanks

lee

 

sounds like either a loose connection (probably at the alt) or a loose belt.

 

read here -

http://www.ausrotary.com/viewtopic.php?f=16&t=33676

it sounds like you have a series 4 and just connected the original electrics to the series 6 alternator..

ie wont work properly.. as they are totally to different styles of alternator

 

shouldn't be spiking then, it should be more that the car has it's battery being drained when he turns the car off.

 

nope

this is exactly what they do when they are connected wrong..

as the reg gets confused as it doesnt have a correct reference point and tries to compensate.. this over works the reg and fries it..

ie any less than 1 volt drop from B+ to field connection and it will do it..

also by running a link wire from the B+ to the field connection sends the reg funny as well..

both B+ and feild connect have to be from the battery source and the charge light circuit needs to be connected for it to function properly.


also if the reg ***** itself, it turns into a parasydic load on the battery when the car isnt running and the alt needs to be services when this happens..

a clip meter will show the feild circuit with anywhere around 5 to 8mA or more drain if the reg has died.

ive done well over 50 of these conversions now, plus trouble shooting other peoples installs.. seem to always see the same pattern if you read the thread i posted to ausrotary..

if its connected exaclty like i have shown in my diagrams no problems you should have

 

it is a s5. i bought the car with the fd alternator. to the best of my knowledge it was working correctly until the other day

 

My S5 has the same issue with its FD alternator except its never turned off before. I was just wondering what it could have been as well.

 

See on a S4 the only difference is that the reference line is coming from the ignition switch instead of the battery. So with the Key On, it is exactly the same as a S5 or S6 setup (as long as the reference and field have been wired correctly in the first place- if they haven't then he probably has wasted the diode anyway).

It should be wired like this:



Of course the original poster has not said that he just installed the alt... so based on that, we can probably assume that it has been wired and running correctly until this test drive of his, unless he simply left off that pertinent information.

 

The alternator was not originally installed by me. I did pull the motor to do a clutch change. Previously it was working correctly. I never had any issues... although i have only driven the car 100 miles or so.

 

ah ok


well series 5 rx7 to series 6 alt is a straight plug in and bolt up operation, no wiring changes needed (just pulley change needed..)


get your alternator serviced and make sure no one has swaped the pins in the 2 pin plug that goes in the side of the alt!!

can be tested with a mulitmeter as one pin will have constant volts the other will get volts when ignition is turned on..

make sure the constant volts is going to the S terminal
igntion to the L terminal

as with ya battery being drained im betting the reg inside the alt has died..


after putting repair alt on you should see around 14.7 volts charge rate (cause of low battery voltage).

go for a drive and it will drop to around 14.1 volts which is perfect.

 

just went and checked around the enginebay. It is wired correctly. The top pin has continuity with the positive battery terminal whihc is in the rear bin. I did not test the lower pin which is the output to the volt meter. I will take the alternator to get it tested tomorrow

 

Being pickey. .......The pin that does not get consant power 24/7, is just for the Warning light. It does not feed the volt meter. Like I said, picky.

The term Lower pin throws me off a bit. That term does not sound quite right for that alternator.........unless it's from a FB.

 

yep it doesnt feed the volt meter

its the warning light circuit, by feeding the alt in that pin tells the alternator to activate and start charging..

it is a very important part of a load sensative alternator..

not running it will send the alternator stupid as well..

 

Perhaps you are mistaking the circuit or I am not understanding what you are saying.

The L Pin or reference lead is simply a lead from either the CPU or idiot lights/dash.

If the wire has ground on it, it completes the circuit and turns on the charge/alt failure light. On the S4 for example, one side is on the pin 85 of the relay in the CPU, with 86 hooked up too ignition. Other series are similar but driven by transistors instead of a relay. The alternator does not use anything on this circuit as there is not sufficient current to drive anything including a relay or transistor.

Perhaps you are thinking of the S terminal which is the feed. This is what the regulator is using as a voltage reference to "see" when it needs to ramp up the voltage/amperage.