Hi folks, I hope somebody on here might have come across this fault before and be able to shed some light on it for me. First of all I probably need to give some history so please forgive me for this next large piece of text...






My girlfriend's Punto Mk2b was constantly needing to be jump started if she did not use it for more than 2 days running. I had also noticed that on occasions the power steering would drop off and the small steering wheel shaped light would illuminate on the dash. This was usually solved by simply pulling over and restarting the car (but not always I might add).
As mentioned the car was regularly jump started and would run fine unless it was left for a couple a days however one day my friend jumped it for me from a spare battery he had and I'm pretty sure he wired it up back to front although he won't admit it. The headlights lights came on along with all sorts of dashboard lights etc. and there was a slight burning smell before I got out the car and yanked the leads off. When we reconnected them the correct way, the car started but as soon as we removed the leads it would die.
I installed a brand new battery as per the instruction in my Haynes Manual and the car started fine. I checked over the battery with a meter while it was turned off to find that the battery was draining. I solved this problem by removing a badly wired aftermarket radio (the constant live / canbus / lack of switched live problem). This has solved the drain on the battery however the power steering is no longer functional. My confusion is that there is no steering wheel warning light but the battery light remains on. I have also checked over the battery while the car is running as it does not increase in voltage above 12ish as I would have expected if the alternator was working.
From the history of the car I had assumed that the alternator was previously working since the car would run for hours after being jumped but now it looks like it isn't.
Ok, thanks for reading the whole way through. If you have any advice that could help it would be much appreciated.

while car is on and everything electrically turned off, voltage should be around 14V, in your case only 12V, thats not enough to charge battery, dont know if wrong jump starting can kill your alternator but you either got worn out alternator brushes or whole alternator is bad

bottom part of pic is voltage regulator, inside of that are also brushes, you can replace that or solder new brushes on or whole alternator


https://www.fiatforum.com/punto-mk2-2b-guides/284983-changing-fiat-punto-1-2-8v-mk2-alternator.html

Sounds like something got fried on the jump - possibly the alternator regulator/rectifier.
The power steering takes a lot of power and if the battery is being drained or is just old the p/s will trip out on undervoltage. This was probably the original problem. Lights coming on at the jump points to reversed polarity. This can fry the ecu.
I would get the alternator checked out by an autosparky and take it from there. It's possible the p/s will never get up if no charging is detected after startup.
It's possible a fuse has blown somewhere. Worth checking them out especially the big ones in the engine fusebox.

Bairdy said:

the power steering is no longer functional. My confusion is that there is no steering wheel warning light but the battery light remains on.

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I had a similar situation with the power steering light not coming on. My alternator totally did not work at start up. Battery light came on. Power steering light remained off. Power steering did not work. However after about a minute the alternator would produce full power and the steering worked fine.

judderbar said:

I had a similar situation with the power steering light not coming on. My alternator totally did not work at start up. Battery light came on. Power steering light remained off. Power steering did not work. However after about a minute the alternator would produce full power and the steering worked fine.

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Thanks for your reply and input. Unfortunately I have repeatedly tried starting the car, if only to run the engine for several minutes but I've had no such luck with anything starting to work again. All I'm succeeding to do is gradually flatten my new battery. Thanks anyway.

Brendan W said:

Sounds like something got fried on the jump - possibly the alternator regulator/rectifier.
The power steering takes a lot of power and if the battery is being drained or is just old the p/s will trip out on undervoltage. This was probably the original problem. Lights coming on at the jump points to reversed polarity. This can fry the ecu.
I would get the alternator checked out by an autosparky and take it from there. It's possible the p/s will never get up if no charging is detected after startup.
It's possible a fuse has blown somewhere. Worth checking them out especially the big ones in the engine fusebox.

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Yeah, my fear is that the burning smell I described was something cooking! I've been optimistic that the ECU is ok as the car appears to start fine with only the warning lights I've described being on along with the usual start up lights on the dash - nothing out of the ordinary. I've pulled almost every fuse that I can find both in the engine bay and at the drivers side but they're all good. Looks more and more like I'll have to shell out for a new alternator after all. Cheers for the reply.

flisko said:

while car is on and everything electrically turned off, voltage should be around 14V, in your case only 12V, thats not enough to charge battery, dont know if wrong jump starting can kill your alternator but you either got worn out alternator brushes or whole alternator is bad

bottom part of pic is voltage regulator, inside of that are also brushes, you can replace that or solder new brushes on or whole alternator

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Hi there, thanks for your reply. I've seen your reply along with a couple others (in reverse order) and I'm now beginning to circle around getting the alternator professionally checked and if required changed out. Your post has pretty much nailed the coffin for me. Thanks for taking the time to respond.

Thanks to all who responded to my problem a few weeks ago. I finally managed to set some time and a wee bit of money aside and just replaced the whole alternator. This seems to have solved my steering problem for the most part. The car has driven fine now for a week or so with the steering light only coming on briefly once, but this time the steering symbol came on, not the battery so maybe just a small glitch with the electrical steering itself which I've heard is quite possible :-/ . Anyway, thanks again for your contributions.
Bairdy.

The p/s needs minimum voltages to control itself and if the battery is not in good shape the voltage drop at cranking will trip out the p/s.
Check and clean the battery connections and the earth strap terminal at the top of the gearbox. Have everything switched off for cranking. Have a look to battery age and Ah rating. Some of the early cars came with 27Ah batteries fitted, most should be mid thirties to ensure enough reserve to stop the p/s dropping out. Some have fitted 40Ah and over to deal with this.
Give the battery a few days to charge up and then check
12.6 V cold ( ideal perfect new battery 100% charged)
13 ish at idle
14+ at 2000 rpm or over
12.9 ish hot after a run for example.

As winter is on the way might be no bad thing to get a free health check done on the battery. Give yourself time to shop if needed before a replacement if forced on you

i got 13,9V on idle everything electrically off

winter is coming

flisko said:

i got 13,9V on idle everything electrically off

winter is coming

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Nice one. That's not going to run down going to the shops and back. Charging is like pumping air into a tyre. The charging system ( pump) has to be capable of a higher voltage ( pressure) than the battery ( tyre). If it's only slightly over, charging is slow. If too high the battery gets cooked. 14.4 Volts is a happy maximum for the system. Mid to high thirteens at idle is good although if you check a battery immediately after a run you'll see thirteens so at idle not much charge is going in.

never measured it after a run

Try it and you should see it fall back slowly to the 'battery voltage' as it cools over the next few hours or overnight. Same thing happens taking it off a charger.

Tbh the punto alternator ISN'T big enough to power all the electrical gizmo's of winter running IMO

With all the lights on, fans, rear demister, stereo, Phone plugged in charging and sitting in traffic, the voltage regulary drops - seen quiet a few

Yet you get a diesel with a big alternator and its fine?
60A vs 100A alterator - i'd fit a 100A if there was one

Ziggy

I found with two different Denso MS 1022118440 70Amp alternators for my mk2b that I got 14.04 volts at idle. All the voltage regulator is doing is cutting the power going thru the brushes when it reads 14.04V and then switching it back on again as it drops below 14.04V and then doing that very rapidly. As far as i know it is not interested in what the battery voltage is, instead it just responds to whatever voltage can be generated by the alternator for the various circumstances.

At idle, I get 13.88V with interior light, heater fan on full, side lights and headlights on dipped.