Author Topic: alternator went and now no tach after replacement (Read 5549 times)

sethyboy85 · « **on:** March 14, 2006, 01:26:29 pm »

I was cleaning some carbon out of my car getting onto the highway yesterday when at 4800rpm my tach and battery light died/lit up... I thought I popped a belt, nooo so I drove home as quick and safely as possible since I was running out of day light.

get reamed buying an alternator
install it today and now the battery light is gone when I start the car up (self excites at 1100rpm) but no tach it doesn't work... I can't find my multimeter for the life of me to check if any voltage is coming out of the W terminal. checked all fuses traced W and W+ line from alternator to firewall where they disapear (appear to be fine) cleaned the connectors, still nothing.

I am done freezing my ass off but if my battery light isn't on I should be charging right? I drove around for 15min with fan on high, lights on, stereo on all the way and dome light on. never lit up the battery light

when sombody gets home I am going to have them find my multimeter they used last so I can check to make sure I am charging.

why does my tach not work? did it send a surge and blow out the tach, I have an extra one on my desk here but im not pulling that dash apart to get the tach out tonight.

wyldman · « **Reply #1 on:** March 14, 2006, 02:07:58 pm »

Maybe the W terminal isn't connected inside the alternator ?

sethyboy85 · « **Reply #2 on:** March 14, 2006, 02:43:43 pm »

I got the multimeter... have 12.3v from alt to battery neg or alt to block, have 12.3v from W+ to block or neg battery and 0v from W to anything....

so did the punks forget to hook up the W terminal considering it's a $190 alt I am going to raise hell

regcheeseman · « **Reply #3 on:** March 15, 2006, 05:18:42 am »

Quote

I got the multimeter... have 12.3v from alt to battery neg or alt to block, have 12.3v from W+ to block or neg battery and 0v from W to anything....

First off, you mean D+ not W+ right???

You won't measure much from W term (and ground/block/earth/neg) with a multimeter - you may get something if you switch to AC voltage measurement but it won't be much.

It is incredibly unlikely that the terminal is not connected.

If you've got a spare tach, bodge some wires on and connect it up to your alt.

sethyboy85 · « **Reply #4 on:** March 15, 2006, 07:35:47 pm »

no the directions I got with the alternator were very confusing, as in their lableing method... so I had to clean up my old Alt today to read what I had it plugged into before and moved one wire from the W+ to the D+ pin and all is better now... the directions were gay

hillfolk'r · « **Reply #5 on:** March 18, 2006, 04:42:38 pm »

w lead is ac power,,,,read ac on that,,its from the stator output before the diodes,,,i mod old alternators,so i canhook my vdo dieseltach up in my rabbit,,just soldering a wire in there no problem,,,either it isnt the w lead,,or your tach is fried,maybe like if the stator shorted or something,,but idoubt that, i remember reading the ac voltage on the w lead rises with rpms,,,,lamp is out you should be charging,,i bet that w lead isnt correct or somethin like that,,,i coulda swornit read like 7 volts at idle and the most i saw was like 12 but i didnt rev it much,thats on the w lead,reading ac on your multimeter,,cool you got it working,,,i called a few alt shops at first when i got my tach,,because ididnt know what a w llead was,,niether did they,,,,after calling vdo, they faxed me how to get a w lead out of any alternator, they were great,,that was funny,they didnt know either,these auto electric rebuild shops,,this was before iwent to school,and was trying to learn about cars,and after that i knew that if you didnt doit yourself,it wasnt gonna be right!!! if ya get a chance sethy,,check it again,,i cant remember the voltage,,but basically the tachis reading the frequency change,,the ac for the w lead is just a signalwire basically