Technical alternator changed/battery light when starting?

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Technical alternator changed/battery light when starting?

my alternator gave up 14 days ago today ..having previously read this thread ,i just bit the bullet and got my replacement from the dealer along with a new tensioner and belt ...i just couldn't be bothered with the thought of a different manufacturers not putting the light out and possibly overcharging ...also the thought of removing the aircon pump again ,,.then again as a mechanic i like most cant be bothered working on my car more than i have to..after spending all day looking at trucks lol

if you want a quick fix then dealer is best ,though if you don't mind liasing with other manufacturers then obvious if they are cheaper then go with them
 
just digging this up to say I had a genuine alternator from fiat at £297 fitted by a mate today and its working perfectly, looks like its non genuine items the cars wont take to
 
Apologies for digging up an old thread, but I have the same problem. I've run my fiat into the ground but was hoping to get rid this week. Probably only worth a grand now. It needed a new alternator, so got it fitted but now the battery light is on until you restart the car and all is good. Guessing the alternator is not compatible as it is a unofficial aftermarket part.

Obviously cant get rid of the car like this. Did anyone find a solution without having to change the alternator again? Reluctant to pump anymore money into the dam thing.
 
Old topic but still valid I think :(

Same problem here.
I recently changed my alternator on a Grande Punto 1.4 8v.
My old alternator the housing was cracked and rotor was hitting the stator sometimes which resulted in bad noise.
After I changed the alternator same symptoms as described.
The alternator I got is from a german car parts shop on ebay.
(not yet allowed to put a URL here.)
It's not genuine and costs around 85 euro.

What seems to help :
Switch on ignition, wait around 8 seconds and start the engine.
Until now this seems to work.
But when I switch ignition and start directly sometimes the battery indicator light stays on and no power steering.

If I cannot solve this with the supplier I am thinking about fooling the electronics (one input on the ignition module is sensing the D+ signal which comes directly from the alternator.)
Putting a resistor and a zenerdiode from +12V to this input might fool the module.
First I have to do some measurements for which resistor value (somewhere between 1k and 4k7) and zenerdiode with voltage drop of 7,5V or 8,2V will do the job I think.
 

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Yes indeed!
I also think that the decision made in the CPU for having a low voltage is only one time trigger.
It never decides to check the voltage again and that's why also power steering is switched off.
I can imagine that's a good decision, because power steering can drain a lot of power from a battery.
But at least check again and decide to switch off the indicator and switch on power steering again in case voltage is sufficient.
It would be a better job to check battery voltage lower than 12V after engine is running at least 1000RPM.

The elearn documentation and the schematics are a little bit confusing because from the documentation and the description it looks like the D+ is also getting power from the injection module and I disagree on that, because I think the alternator itself can regulate its output very well.

So I will do some careful measurements on the car and also disconnect the D+ from the alternator and try to fool the injection module input with an external power via a resistor and see what happens.
 
Today I made a testlab with my old alternator to measure some values.

First I thought D+ did not need any external power source, but it really needs to deliver some energy to the rotor to become a rotating magnet.

I used 2 different light bulbs which act as loadindicator for the alternator and rotating the rotor with a drill I managed to make the alternator deliver power to the battery.

The bulbs I used where 12V 1,2W and 12V 5W.
both made the alternator work fine and they give a preload current to the rotor of 54 mA and 320mA respectively.

So I think when I increase the pre-load current on the new alternator this will do the job. (waiting now for the GP to return home) :)

The attachment shows the schematic principle of a modern alternator with + en D+ connections only.
 

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Today I could work again on the Grande Punto.
Measurement on the pin 5 of connector D029 shows a voltage drop of around 0,9V. (With only ignition switched on)
This means an estimated 50mA rotor current.
I increased this current a little bit more by connecting a 12V 1,2W light bulb between pin 1 (+12V ignition coil) and pin5 of connector D029 (right below the injection unit)
This already helps a little in reducing the amount of battery light errors after quick starting.

I have 2 other ideas which need to be tested also:
idea 1:
Place a capacitor 1000uF to start with on pin 5 D029 and earth.
This capacitor should flatten the voltage from the coils and also will increase the DC voltage which is measured by the injection module.

idea 2: Put a rectifier (e.g. 1N4007) between D+ connector on alternator and the wire which comes from the injection module.
By putting a rectifier in between the voltage on the input of the injection module already increases from 0,9V to 1,6V and I assume a pull up resistor is used in the injection module so it will be easier to reach the 5V threshold when the alternator starts generating power and voltage.

(Ideas 1 and/or 2 could possibly replace the first adaption with the extra light bulb.)
To be continued soon :)
 
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Today I used the car to drive to work and I only waited around 1 second to start the car (after ignition switched on) and no warning lights on :)
So that's already a big improvement and almost acceptable.

I already made some preparations to test my idea's I wrote before.
First I want to start by only adding a 1000uF capacitor on D+ and car earth.
(I will remove the 1,2W bulb first to check a solution with the minimum of modifications.)

When that's not sufficient I will try idea 2 with the diode in the circuit.

In the first picture I show the diagram and the hardware solution:
attachment.php


Th next diagram shows all possible adaptions:
attachment.php


Sorry for my bad drawing and writing :)
 

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...

idea 1:
Place a capacitor with a value of 1000uF on pin 5 D029 and earth.
This capacitor should flatten the voltage from the coils and also will increase the DC voltage which is measured by the injection module.

This one might do the job :) :D


Just tested this one and I tried a few attempts to get the battery light on (very quick turning of the key)

This picture shows the needed hardware (also add washer and m6 nut for earth):
attachment.php

This shows temporary test in the Grande Punto next to connector D029 pin 5:
attachment.php



Final connection will be soldering on the wire itself after removing some isolation.
 

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I found some spare time to install the capacitor in a decent way.
Now I can start engine directly by turning ignition on and starting immediately and no warning light on anymore.
I had to delete the old P0621 error in the ECU and I expect that one will not return again.
So only one capacitor 1000uF /16V or 25V should solve this issue for others with the same problem.

The pictures from installation:

Removing isolation and sticking through the cable
attachment.php



Soldering:
attachment.php




Isolation and earth connection at the injection module housing:
attachment.php




Job finished.
Hopefully this error will never return again.
 

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Yesterday I checked with MES the motormanagement module and found no more P0621 error anymore.
In the last week I did a couple of cold start attempts to make the light pop-up, but I did not manage to get it on :)

I also tried a capacitor with lower value (put 470uF serial to the already connected 1000uF which gives about 320uF value)
Did also did not give any warning light on.
So today I decided to replace the 1000uF Capacitor by 470uF and also connected it more decent nearby the connector D029 etc.
In the picture you can see the final solution for my car:

attachment.php

The seller on ebay gave me a full refund. So everything solved in a decent way.
I did not want to replace the alternator again Because it's a hell of a job with no bridge available and a real struggle to loosen and fasten the upper bolt.
 

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Just wanted to say that the "cold start" trick, i.e ignition on and wait 5-10 secs before turning over really does work. Am going to fully digest damteds post and attempt the capacitor mod and hopefully get rid of this annoying problem!
 
Just wanted to say that the "cold start" trick, i.e ignition on and wait 5-10 secs before turning over really does work. Am going to fully digest damteds post and attempt the capacitor mod and hopefully get rid of this annoying problem!

Thanks for the feedback :)

To be honest it has become my 'normal' procedure since the Grande's inception..

My 2004 panda highlighted that the self.test needs to run fully..

I just wait for the fuel pump to finish priming.. then another fun journey begins :)
 
Thanks for the feedback :)

To be honest it has become my 'normal' procedure since the Grande's inception..

My 2004 panda highlighted that the self.test needs to run fully..

I just wait for the fuel pump to finish priming.. then another fun journey begins :)

It's pretty much essential to do on a diesel in winter time unless you want to crank for a while due to glow plugs not being hot
 
Just wanted to say that the "cold start" trick, i.e ignition on and wait 5-10 secs before turning over really does work. Am going to fully digest damteds post and attempt the capacitor mod and hopefully get rid of this annoying problem!

Update:
Still working fine. So it's worth to do.:)
 
Same problem here. I recently changed my alternator on a Grande Punto 1.4 8v. ...... After I changed the alternator same symptoms as described. The alternator I got is from a german car parts shop on ebay. (not yet allowed to put a URL here.) It's not genuine and costs around 85 euro........ But when I switch ignition and start directly sometimes the battery indicator light stays on and no power steering. [/QUOTE said:
Good morning..
My 1.4 8v with aircon, had a recon alternator fitted some 4 years ago. lately the same issue as above started cropping up.
Last Friday, with engine running, the battery light only came on at above 2000RPM, then stayed on. Steering light likewise. Steering worked, then cut out, then worked? Cleaned the earth cable contact points, all the fuses at the battery positive and also both terminals. Fiddled with the alt wires from below, seemed to be tight.
Car started, no strange lights, etc on dash. Steering worked. My wife drove car to town, only told me yesterday, the battery light came on.

Tested car yesterday, the steering motor would work intermittently and dash battery / steering lights came on randomly. Left car on charge all night, tested this morning, 14.2v.
Started car, battery at idle with no battery light on the dash, voltage dropped to 12.8v. I increased revs above 2000RPM, still no charge but now lights came on.

This is not normal?

I suspect the alternator needs to be removed, how do I reach the top bolt(s) without loosening / removing the aircon piping? The aircon pump was recently overhauled and regassed.

Please excuse my using this post, thought the strange dash lights sequence may be associated somehow.

Thanks,

Edd
 
Sorry for digging this Thread up after nearly 3 Years.

My wife drives a Fiat Grande Punto 1.2 with 69hp.
Two weeks ago, the battery light came on and we smelt some "burned" electronics. The original alternator died on us after 120tkm.
Luckily we were still able to drive the car to a local workshop. The steering started to became stiff. The car has a recently new battery (2 Months old) and probably thanks to this we were able to move the car to the workshop.

The mechanic told us, that the alternator was bad and even had a big crack.
He replaced it with a new 120A generator, I yet have to ask the guy which brand the new unit was. It definitely is not a genuine one. The replacement costed 260€. I assume a new one from the FIAT dealer would be twice as much.
Long story short: I now have the exact same issue!

On random startups (1 out of 10), the battery light comes on and steering is stiff. Shutting down the car and starting it again fixes it. While driving the issue is not reoccurring. The battery is new, the alternator is new. I also cleaned the grounds and then I found this thread here.

I'm not eager to replace the alternator again, but just out of curiosity:
What is the original brand for the 120A Generator in a GP with A/C and Start/Stop function?
Is it a Bosch unit? I was not able to find a 120A Magneti Marelli unit.

I have no problems turning on the ignition for a few seconds, but this car needs to undergo annually inspection and I fear that this error pops-up during it.

I also think to try the capacitor mod described by @damted .
I'm proficient in soldering but not in deeper electronics.

Why is a capacitor "helping" with this kind of issue? I understand that providing a load in form of a bulb between 12V+ and D+ increases excitor-current, thus making the alternator quicker ready. But why is a small cap between earth and D+ sufficient for this case? Aren't they just for smoothing voltages when installed in such a setup?
 
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