Technical Alternator only starts generating after revving
- Thread starter nigelvan
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Technical Alternator only starts generating after revving
Well, yes this is what I was thinking too. I can 100% confirm there is no fault in the wiring because I ran a complete separate wire (one that could easily carry several amps without loss) straight from the BCM directly to the D+ pin, also did multiple resistance measurements over the existing wiring. I wanted it to be a wiring problem haha.
I did say that after installation of the original voltage regulator the problem was briefly fixed. I also measured the current then and I also read about 30mA. So the same current as always. @jackwhoo as @koalar pointed out, could it be that this type of regulator takes a very small current from the computer in order to wake up the IC and it then takes power from B+ to power the coils?
Anyway, we will indeed know more when the new regulator arrives.
I will measure the pulleys when I replace the regulator.
I have a feeling that your hope bcm is not faulty is skewing your thoughts toward it must be the regulator.
When you get genuine regulator and fit it please measure current between BCM and L on cold start , in case BCM intermittent and supplies more than 30 milli amps.
The end result will be interesting.
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The information above description is measured from a couple of my alternator alternators
Below is from a seller on Amazon
The information for the F00M144128 is patchy at best, different seller different descriptions, best guess
L probably has a relay output driver as the optional internal cabin heater runs from here, mentioned by several sellers
But Fiat might install the a different part if the heater fitted, who knows
Couple mention the regulator self exciting function, but again how reliable this information is
NEW Alternator Voltage Regulator 13420700 04-0221 F00M144126 F00M144128 F00M144136 F00M144153 F00M144154 F00M144180 F00M144195
A-Circuit Voltage set point 14.60 VI could not find any schematics for the regulator, anywhere and I looked quite hard
@koalar Appreciate it. I also looked quite hard online. I'm used to long datasheets/schematics from the electronics world. So it could be possible the regulator is not completely compatible with the old one.
I realized the expected 1.5V @ 0.03A corresponds to the 50ohm (just ohm's law) I measured before, which changed into 68k when I took the alternator off the vehicle. So it 'does something' when the alternator is powered by B+.
@jackwhoo Well the BCM seldomly fails, right? I have experience with microcontrollers and embedded electronics and never seen only one pin fail while still putting out consistent voltages and current. The BCM has been the only consistent thing across the tests, the voltage regulator... we'll see when the new one arrives. Ordering and returning voltage regulators is also cheaper than the BCM, which is way too expensive to replace and needs programming. The bulb fix is still on the table.
If I didn't have so much time or interest in this issue I would have already put in a new alternator, LOL.
I realized the expected 1.5V @ 0.03A corresponds to the 50ohm (just ohm's law) I measured before, which changed into 68k when I took the alternator off the vehicle. So it 'does something' when the alternator is powered by B+.
@jackwhoo Well the BCM seldomly fails, right? I have experience with microcontrollers and embedded electronics and never seen only one pin fail while still putting out consistent voltages and current. The BCM has been the only consistent thing across the tests, the voltage regulator... we'll see when the new one arrives. Ordering and returning voltage regulators is also cheaper than the BCM, which is way too expensive to replace and needs programming. The bulb fix is still on the table.
If I didn't have so much time or interest in this issue I would have already put in a new alternator, LOL.
This hopefully.
Ok guys, finally I got the package. There was some construction in my street and the delivery guy couldn't be bothered to make a 100 meter detour apparently...
So what I've got is a Bosch 1 986 AE0 120, but I ordered a F00M144128. It's listed as the replacement... Well, we'll see.
I'm not at the van right now but I took some readings.
Resistance between L/D= and GND is again 56kohms... Just like the Hitachi, uh-oh
But, I do measure a diode on the same circuit with a forward bias voltage of 1.6V. the old one (the one that starts the alternator at 1500rpm) also had a diode that measured only 0.6V. On the Hitachi there was nothing there. But I will take a last measurement before sending it back to where it came from.
So, with a bit of luck it stays dry and I'll slap the new reg on tomorrow. Going to try that without taking the alternator out. Not sure if it's possible but with a short screwdriver maybe.
So what I've got is a Bosch 1 986 AE0 120, but I ordered a F00M144128. It's listed as the replacement... Well, we'll see.
I'm not at the van right now but I took some readings.
Resistance between L/D= and GND is again 56kohms... Just like the Hitachi, uh-oh
But, I do measure a diode on the same circuit with a forward bias voltage of 1.6V. the old one (the one that starts the alternator at 1500rpm) also had a diode that measured only 0.6V. On the Hitachi there was nothing there. But I will take a last measurement before sending it back to where it came from.
So, with a bit of luck it stays dry and I'll slap the new reg on tomorrow. Going to try that without taking the alternator out. Not sure if it's possible but with a short screwdriver maybe.
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Does not 1.6V suggest two diodes in series. If one was faulty?????
There are rectifier diodes with that forward voltage. so... hard to say without schematics. I'm going to mail the store to make sure I have the right part.
Thanks Jack, that's what I found after a quick google as well. The GTIN is also the same.
Guess we are good to give this one a try then.
BTW: meanwhile the old regulator still holds up. Even if the BCM is at fault we should expect at least the same behaviour, right.
It should behave as the original part
So amigos, the new regulator is on. I did it while the alternator was in the car. It's not too hard if you can get enough pressure on the philips screws. In my case they already had been off so nothing to difficult there.
It's now kind of fixed, but we'll see tomorrow, since last time it also worked for one day with the old regulator... (which is still magic...)
The engine still revs up a bit to about 1000rpm and then the alternator kicks in.
Voltage is stable across the rpm range and load (turned every electrical on and off)
If it behaves like this I can live with it.
I'm actually starting to think this alternator is not meant for this vehicle: it says IVECO on the label, it's an Iveco engine but an actual Iveco Daily might have a bigger pulley on the crank which gives the alternator more rpm. Although I doubt that scenario...
btw here a the dimensions of the pulleys: crank about 14.5cm, alternator pulley about 6cm in diameter.
It's now kind of fixed, but we'll see tomorrow, since last time it also worked for one day with the old regulator... (which is still magic...)
The engine still revs up a bit to about 1000rpm and then the alternator kicks in.
Voltage is stable across the rpm range and load (turned every electrical on and off)
If it behaves like this I can live with it.
I'm actually starting to think this alternator is not meant for this vehicle: it says IVECO on the label, it's an Iveco engine but an actual Iveco Daily might have a bigger pulley on the crank which gives the alternator more rpm. Although I doubt that scenario...
btw here a the dimensions of the pulleys: crank about 14.5cm, alternator pulley about 6cm in diameter.
Is that different behaviour to how it was at very beginning?
Does the engine rpm drop from 1000 after alternator starts?
I would expect the alternator to start providing power around 750 engine rpm.
If you power L via a small bulb does the alternator start at lower engine rpm than 1000?
