I need some help on this one, very confusing.

I got my skoda felicia 1.3 1997 a few months ago and it had the common problem of the airbag light on and over charging the battery (very high voltage). so i got a new voltage regulator and that fixed the problem and got the airbag light put out succesfully,

2 weeks later the voltage was very high again but airbag light didnt come on, so i got another voltage regulator from the scrap yard and that fixed the problem again. a few weeks later i also fited a new speedo with a rev guage which has caused the airbag light to stay on but i have had it checked and the airbag has no problem and they dont know why the light is on which is confusing. so dont know if thats the problem?

i also fitted a new battery a month ago as the last one would not hold charge very well, due to being boiled.

last week the alternator light started to glow when the revs got higher but the voltage was not over 14v, i then ordered a new voltage regulator which i fitted last night but didnt 100% fix the problem, the light was hardly on but you could see it get slightly brighter. then on the way home tonight the alternator light has gone back to being very bright when being reved. but the voltage changes from 12.5-13.9v so not high at all, the alternator has started to whine a little with the revs. the battery is still being charged but the light is still on, very confusing.

i have now decided it must be something else than the voltage regulator as i have tried 3 now. i am going to swap the speedo back to see if that puts the airbag light out. the only thing i can think it is, is the alternator is faulty, ie the diodes.

Does anyone have any ideas?

also the alternator fitted is 70amp is this correct or should it be 55amp as i dont have aircon or power streering.

Any help would be great

Cheers

Mark

Well, i'm looking for a 90amp alternator.... so no, 55 amps is very weak, but if the voltage regulator is getting Goosed (jejeje, learned that one here) then your problem is something that is shorted out

remove the battery with the car running an have a reading on the amps and the volt that the regulator is pushing out to make sure, you should get 14 volt, and rev the car up an down a couple of time slowly and check the amps, if the regulator is fried you should see amps going up and down as well.

are you getting problems outside the dashboard?, did you install wiring for A/V, new radio, modified headlamps or security system ?

please us know, cus i dont think alternator is the problem

I agree with your diagnosis Tonny, and that's exactly the correct way to use "goosed" in this context too!

right then last night the car nearly died on the way home, the alternator does not seem to be charging the battery enough so all the lights were very dim on the way home.

i dont believe it to be shorted out i think the alternator has truely gone and and i havent installed anymore items to the car. anyone know the cheapest place.

what is the reason for not thinking its the alternator?

cheers mark

The symptoms you describe, apart from the voltage which is acceptable, are all typical of a failed control box. The failed control box would usually see the voltage well over 15v, and on the way to frying the ECU! :eek:

I would check the heavy duty cables next.

failed control box? whats that?

the voltage is low not high, i changed the voltage regulator as the voltage was way over 15v last time.

Where are the heavy duty cables?

sorry for all the questions this is my first skoda, and the everyday work car so not 100% on where the parts on unlike my fun weekend car lol.

cheers Mark

Control box = regulator.

Heavy duty cables - feeds and earths from alternator, battery, starter motor and block.

oh ok, well i might send the regulator back as it might be broken, but i cant of had 2 broken ones from the same company jorilly? yer i will check the earths but i think its the alternator as the voltage is not higher than 14v

I'm suggesting checking them because a high resistance there fits with a good alternator and regulator, but poor supply to devices.

how would you check them?

Make sure the terminals are clean, and the terminal bolts tight. It may not be the problem, but it's at least reasonably easy, quick and cheap to do to eliminate them as a problem.

here i something i would if i was experiencing the same problem.

unplug all the fuses, check all of the ones i'm fitting are of the correct amp, have a tester ready and connect it to the two terminals in the battery,

check voltage write down value, then have a friend start up the car

check voltage again and write down value and keep a note of car state while reading value

turn on all the things in the car (without fuses on) make note of items that turn on

check reading if arround the same as car running make note of working accesories

put one fuse in at a time (correct amps) and every time check voltage reading

if you do this you ARE going to find that the voltage WILL go down OR fuse will burn

NOW, the only reason i belive the voltage regulator is getting fried is because is getting a pulse of high voltage, this high voltage is leaking through your system and is probably affecting the battery too,

only thing i can think of is a transformer (not a autobot or decepticon) from a Xenon system, Stacked High power Capacitors from Audio / Video Setup, DC/AC converter or something of the sort, or

something is storing energy, when is full, it shorts out close the the alternator sending all the amps it stored in a single pulse (very fast pulse could be doing several times before regulator giving up) thus goosing the voltage regulator in the alternator (im so proud of myself for learning that word, cant get enough of it, jajaja) and in the meantime giving you a low volt reading

now thats my idea, but with no tester in my hand and access to your car, i wouln't be supised if it where just a monkey in a hat :S (meaning it could be anything)