alternator issue ???
 

hi all ,
i have a bit of an issue with the voltmeter in dash on my 1980 928s , i only have the car a couple of weeks , and is on the to do list !!!....when i put on the turn signal left or right or( brake lights ) the voltmeter in dash jumps up and down in time with the turn signal , issue was there when i purchased the car p.o said he had the alternator out of car and it tested fine, seemed to be a straight up guy and i have no reason not to beleive him :rolleyes: so i was thinking bad grounds maybe and an easy fix ,
but today after a drive of 1 hour 30 mins in daytime got home car sat 30 mins got back in no start i had to jump start her, battery seemed dead !! no issue before today .. anybody know where i should start on this one could i be lucky and it be voltage regulator on the alternator ? or is this alternator defo ????
its 30degrees centigrade here today ambient temp which is hot for ireland could this have effect on alternator performance ? ( charging battery )

this issue just moved to the top of the list , nothing worse than jumping into a 928 and nothing happens http://forums.pelicanparts.com/support/smileys/chix.gif

Check the battery ground cable, both mechanically and electrically. Use an ohmmeter if possible while flexing the cable. Many look good but are corroded at the crimp. This would explain your symptoms.
One method to test is to use one jumper cable from the - battery post to ground and try to start. It could also be many other things, including the battery, + red cable, etc.
Dave

My volt gauge flicks with signal, sunroof, windows, etc. and my charging system is good. Always has flicked. My Battery is at least 3 years old. Meters not that dependable from what I have read. I replaced my ground battery strap and had improvement at volt meter and less flick iirc.

Check charging system at jump start terminal. Others will chime in with suggestions.

And what outback said.

A fully charged battery should read about 12.56 volts. With engine running you should read about 13.8 volts. Get a good volt meter and take readings right at the battery.

Cheers guys , I had already redone the battery ground no improvement , the age of battery is unknown but it is not the correct one it does not fit into battery housing properly so a new battery has been on the list from day one , but I wanna make sure all is ok with charging system before I ruin a new battery , I will work on above suggestions and post back any news 😀

Bottom line, check the obvious things first, battery for one. Battery connections, voltage, charging conditions. I bought the proper battery at Walmart at a decent price.

ok , pulled the battery gave it good charge overnight , 13 v out of car , in car nothing on 13v
lovely jump in lots of lovely bright lights on dash turn key to start ......nothing relay panel clicking thats all no motor turning , try jump start ....nothing just clicking from relay panel test battery 13v . but when turning key i dont hear fuel pump,.... checked fuel pump relay bypassed it fuel pump on . check start relay( no. 7 )bridged it out turn key engine fire straight away .
faulty start relay (very strange) .
checked battery engine running nothing on.. 14v at battery ,.... lights on,.. fan on full ...14v at battery! it that a good sign from altenator ? charging system ?
new relay needed !

Looks like it is charging OK. Sounds like a relay, switch, ground or connector issue. You may want to go through the CE panel, clean all fuses and relay contacts. I went and just replaced all the common relays, they are not too expensive. Pull all fuses and clean contacts.

Thanks guys
Yeah ce panel is pretty tired looking a refurb is defo needed , the list is getting longer the more I work on this car the bigger it gets 😓

Welcome to the Club :cool:

When you turn the key to start position - what voltage do you see on the dash voltmeter?

Sounds like a classic degraded battery in which case you are probably seeing about 6v during cranking - this is not enough to start and is not enough to keep relays engaged (the clicking).

Take the battery in and have it load tested - a load tester is not a handheld device - its a big carbon pile resistor device in a cage bolted to the floor - make sure they use that type of tester. Your battery will likely be toast under heavy load - get the proper sized replacement

Alan

thanks alan ,when i bridge out the starter relay the car fires up perfectly so i reckon battery is good , but i have since discovered im not getting any voltage at all accross the coil of starter relay 0 v when turning ignition sw is on to start , traced it out of relay board i going to pull the pod and check ignition sw. im going to investigate a bit more this eve and will post any more info !
p.s ...... the headlights went up last night but did not come down im hoping it just related to me pulling at the relay board .....the never ending story !!!!!!!!

http://forums.pelicanparts.com/support/smileys/wat1.gif
you gotta love it :)

ok , problem solved i did some proper investigation on the start relay . tested relay in house works perfect .checked terminals at relay board found i have sw wire + from ignition sw but no negative - across the coil . i traced the - wire into a loom that heads to the back of the car into spare wheel well where there is a junction box/cover ( still with me ? ) ok i had been at this junction box the other day while i was re doing battery grounds and i had a look and redone 3 electrical connections , i should have redone 4 !!!!!!!! i obviously disturbed a very badly done connection by a hack ! which for some reason is the -for the start relay ! car starting power full lovely
also on the headlights cleaned 4 pin connector at headlights and all connections at the relay male and female still no lights down . with car running and sw off , i started to manually lower lights , when i got to a certain point they would lower themselves a little bit then stop again!! manual lower again then motor would kick in again and complete the lowering auto.
i messed around with the manual knob rotating 1x 360 revolution to try and get the limit sw's to realign themselves and this seems to work lights go up lights go down ( for now) it could be the contacts on the famous disc inside the motor need to be cleaned !!! another one for the list !!!!
thanks for all the kind input guys really appreciate itSmileWavy