Technical Fiat 500 alternator removal!!!!
- Thread starter HammerFL
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Technical Fiat 500 alternator removal!!!!
'Beautifully Formed Hammer'..?
Yes, exactly.
I am in the process of doing this job. So far I have loosened the two bottom bolts and what I thought was the top bolt. What I thought was the top bolt isn't the top bolt and now the realisation has sunk in as to how difficult this job is going to be. I think I have found the top bolt (by feel) and it seems to have something obstructing it. I think I am going to have to go in from the top just to see what is going on. I'll maybe take out the starter motor just to create more space. Put it this way, I am prepared for the long haul on this one, I'll remove the engine if I have to.
Lol, I too took the starter motor out, and thought as it was such a pain to do the Alternator I might as well change them both, because I ain't coming back to do it later, plus I wanted to check all electrical connections.
Like a previous poster I never had to release axles or whatever, just a few pipe brackets and covers. Patiently wiggling it through gets it out.
I did mine just after xmas, under a tarpaulin, started at about 09-30, finished about 01-30 the next morning, temp had dropped to about -2 degrees, luckily I had a padded overall which kept my body toastie, but frozen hands were a problem, solved by clasping many cups of piping hot tea.
For the top bolt, I used a long series hex socket (not the typical multi-spline type), but the ratchet head wouldn't go completely in (as the socket was a tad too short), so I put the 3/8 square in up to the ball bearing, and applied pressure in one direction to undo it, and concurrently in another to ensure the square didn't come out. After a few turns the rachet has to be removed (theres no room for it) and I was just able to turn the socket with the tips of my fingers. You definitely need the patience of a saint, so being prepared for the long haul, will certainly help.
I was hoping the Twinair engine would offer more space than the other variants but no sign of that yet.
The air filter housing and the battery box are going to come out so I can get lights and mirrors in to actually see what is going on. One thought at the back of my brain is that loosening the air con compressor mounting bolts may allow me better access but I need to see what is going on first. If the bolt I have found is the correct bolt there is something that feels like a plastic bracket right on top of the bolt head that will need to be moved, so I am not at all sure I have the right bolt. I had an endoscope on it yesterday but it is not the greatest and I couldn't see enough to be of any help. Removing the battery box will let me see round the side of the engine and removing the air filter housing will let me see what the score is with moving the aircon compressor. I will be checking the gearshift linkages (a known problem) and changing the plugs while in there so it is not going to be wasted work either way.
The air filter housing and the battery box are going to come out so I can get lights and mirrors in to actually see what is going on. One thought at the back of my brain is that loosening the air con compressor mounting bolts may allow me better access but I need to see what is going on first. If the bolt I have found is the correct bolt there is something that feels like a plastic bracket right on top of the bolt head that will need to be moved, so I am not at all sure I have the right bolt. I had an endoscope on it yesterday but it is not the greatest and I couldn't see enough to be of any help. Removing the battery box will let me see round the side of the engine and removing the air filter housing will let me see what the score is with moving the aircon compressor. I will be checking the gearshift linkages (a known problem) and changing the plugs while in there so it is not going to be wasted work either way.
Well, the alternator is out and I have made some discoveries along the way.
1. There are 2 (at least) variations of the alternator for the Fiat 500. One of the electrical connections has been changed significantly between the two variants.
2. There exists a socket that will allow removal of all 3 bolts using a ratchet handle on the Twinair but may be different for other engine variants.
3. Once unbolted the alternator can stay firmly in place seized on the mounting bushes, not even a hint of a wiggle when pulled to remove from location.
4. On the Fiat 500 Twinair 0.9 2011 the alternator (once freed from locating bushes) can easily be removed trough the space on the drivers side if you undo the clip for the aircon pipe. Absolutely NO NEED to try and prise it out past the subframe. I guess the Twinair engine is narrower then the others so there is more space at the sides. This part of the job took seconds.
1.To demonstrate the two types I have attached photos. Note that the connection for the field enable has changed from a ring terminal held in place by an M8 nut to a plug in connection on the later version. This makes it more difficult to disconnect on the earlier version. I freed the alternator before disconnecting mine because it was such a hassle and when the alternator fell the wire broke at the alternator ring terminal . It may have been broken before I started and when the alternator fell it came loose. This may indeed have been the cause of my charging problem as this is how the related box of electronics (CPU) turns the alternator on and off, which I think may have been a weak point hence the change in connectors. The ability to turn the alternator "off" probably reduces drag on the engine and thus reduces fuel consumption. It may even be a variable signal that actually controls the charge rate. I intend to investigate that as I will mention later.
2. The socket in question is a 100mm long six point 13mm from Laser tools. Please see attached images for details. In order to give myself a bit more space I removed the lower air compressor mounting bolt on the driver side thinking it might help. I don't think I needed to do that as the ratchet handle never made it around that far.
3. As I sussed when all the bolts were loose the alternator was seized on the locating bushes. In addition when the top bolt was loose I couldn't get my fingers in far enough to grip it and pull it out. Rather than end up with the alternator hanging from a partially removed bolt I decided to make absolutely sure it was free. I worked out I was probably turning the bolt by 1 flat every time so six movements of the ratchet would be one full turn of the bolt. Then I counted the threads on the removed bottom bolts, multiplied by 6 and doubled that figure. This came to 250. I then gave the already loose bolt 250 more "turns" with the ratchet and socket to make sure it was loose.
By the way, the drivers side lower bolt seized in the locating bush so even when it had been turned to the point where it wasn't making any more progress it was still tight and could not be pulled out. I got it out by hooking a long ring spanner over the bolt head and using it to lever the bolt outwards while continuing to "unscrew" it. Believe you me, this was after much penetrating oil was applied and it was tight all the way out right up to the end. No pulling this one out with your fingers!
Final removal of the alternator was achieved using a big long masonry chisel with a hammer, this chisel (designed for chiselling concrete, about 25mm thick and 1 foot long)) was applied to the base of the alternator between the two lower mounting bolt holes. Realising I was going to have to do this is why I went to such lengths to make sure the top bolt was fully unscrewed from it's threads. It took about 20 HARD whacks before the alternator came free. I was on the point of getting out my compressor with an air hammer when it eventually came free. Again, I had to be sure the top bolt was free before I went on to apply this much force. If the alternator had been mounted directly on the engine casing I would never have done this but it was mounted on a thick plate which was in turn bolted to the engine so I was happy to give it everything I had when swinging that hammer.
4. I had already removed the bolts securing the engine to the bottom mount as the videos I had watched and all the comments I had come across said this was necessary as the engine had to be moved to be able to withdraw the alternator fully. This is not the case with my 2011 Twinair. I had already undone the clip securing the aircon hose on the driver side in order to maximise space but I suspect it may have come out without doing this. It just came right out with no hassle at all. I could see the gap was big enough before I even tried.
1. There are 2 (at least) variations of the alternator for the Fiat 500. One of the electrical connections has been changed significantly between the two variants.
2. There exists a socket that will allow removal of all 3 bolts using a ratchet handle on the Twinair but may be different for other engine variants.
3. Once unbolted the alternator can stay firmly in place seized on the mounting bushes, not even a hint of a wiggle when pulled to remove from location.
4. On the Fiat 500 Twinair 0.9 2011 the alternator (once freed from locating bushes) can easily be removed trough the space on the drivers side if you undo the clip for the aircon pipe. Absolutely NO NEED to try and prise it out past the subframe. I guess the Twinair engine is narrower then the others so there is more space at the sides. This part of the job took seconds.
1.To demonstrate the two types I have attached photos. Note that the connection for the field enable has changed from a ring terminal held in place by an M8 nut to a plug in connection on the later version. This makes it more difficult to disconnect on the earlier version. I freed the alternator before disconnecting mine because it was such a hassle and when the alternator fell the wire broke at the alternator ring terminal . It may have been broken before I started and when the alternator fell it came loose. This may indeed have been the cause of my charging problem as this is how the related box of electronics (CPU) turns the alternator on and off, which I think may have been a weak point hence the change in connectors. The ability to turn the alternator "off" probably reduces drag on the engine and thus reduces fuel consumption. It may even be a variable signal that actually controls the charge rate. I intend to investigate that as I will mention later.
2. The socket in question is a 100mm long six point 13mm from Laser tools. Please see attached images for details. In order to give myself a bit more space I removed the lower air compressor mounting bolt on the driver side thinking it might help. I don't think I needed to do that as the ratchet handle never made it around that far.
3. As I sussed when all the bolts were loose the alternator was seized on the locating bushes. In addition when the top bolt was loose I couldn't get my fingers in far enough to grip it and pull it out. Rather than end up with the alternator hanging from a partially removed bolt I decided to make absolutely sure it was free. I worked out I was probably turning the bolt by 1 flat every time so six movements of the ratchet would be one full turn of the bolt. Then I counted the threads on the removed bottom bolts, multiplied by 6 and doubled that figure. This came to 250. I then gave the already loose bolt 250 more "turns" with the ratchet and socket to make sure it was loose.
By the way, the drivers side lower bolt seized in the locating bush so even when it had been turned to the point where it wasn't making any more progress it was still tight and could not be pulled out. I got it out by hooking a long ring spanner over the bolt head and using it to lever the bolt outwards while continuing to "unscrew" it. Believe you me, this was after much penetrating oil was applied and it was tight all the way out right up to the end. No pulling this one out with your fingers!
Final removal of the alternator was achieved using a big long masonry chisel with a hammer, this chisel (designed for chiselling concrete, about 25mm thick and 1 foot long)) was applied to the base of the alternator between the two lower mounting bolt holes. Realising I was going to have to do this is why I went to such lengths to make sure the top bolt was fully unscrewed from it's threads. It took about 20 HARD whacks before the alternator came free. I was on the point of getting out my compressor with an air hammer when it eventually came free. Again, I had to be sure the top bolt was free before I went on to apply this much force. If the alternator had been mounted directly on the engine casing I would never have done this but it was mounted on a thick plate which was in turn bolted to the engine so I was happy to give it everything I had when swinging that hammer.
4. I had already removed the bolts securing the engine to the bottom mount as the videos I had watched and all the comments I had come across said this was necessary as the engine had to be moved to be able to withdraw the alternator fully. This is not the case with my 2011 Twinair. I had already undone the clip securing the aircon hose on the driver side in order to maximise space but I suspect it may have come out without doing this. It just came right out with no hassle at all. I could see the gap was big enough before I even tried.
The later connection is the LIN socket (I have made a few posts about this) and confirms the alternator is an 'intelligent' alternator.
The LIN connector comes from the Engine ECU, and is a digital signal to the alternators onboard processor. If connected to an osciloscope or logic analyser the signal will be square wave, and be a handshake signal to check the alternator is of the correct type and within allowable ISO number range. If this check is ok, the Engine ECU will commence charging depending how much the Engine ECU has determined it needs, the processor embeded into the negative battery terminal is used to determine the battery condition.
The LIN connector comes from the Engine ECU, and is a digital signal to the alternators onboard processor. If connected to an osciloscope or logic analyser the signal will be square wave, and be a handshake signal to check the alternator is of the correct type and within allowable ISO number range. If this check is ok, the Engine ECU will commence charging depending how much the Engine ECU has determined it needs, the processor embeded into the negative battery terminal is used to determine the battery condition.
Now that I am ready to instal a replacement alternator I have decided after all the hassle to put in a brand new one. Also I am going to make up a separate battery connection for the alternator so I can remove the alternator in future after disconnecting at the battery rather than having to disconnect the cable between the starter motor and the alternator. This cable connecting the starter motor to the alternator will no longer be needed leaving the starter motor connected to the battery by the original cable.
Regarding the broken wire for the field enable, I will solder a new section on to increase the length and also run an additional wire back up to the battery area. This additional wire will be connected to the alternator field enable terminal by a separate ring terminal so it is a separate wire to the original field enable wire. This separate wire is necessary in order to confirm the signal is actually reaching the alternator terminal. The idea is I have an easy way to attach my voltmeter to check the field enable signal without having to do anything other than open the bonnet. This test wire will be cable tied to the new main battery cable from the alternator to keep it away from the driveshafts etc and will simply be cut to length at the battery end and covered in an insulating sleeve that I can remove when I want to monitor the signal. I think it is possible to monitor the field enable signal using multiscan (and maybe other OBD2 diagnostic units) but that just tells you the signal is being generated at the CPU end. Being able to to confirm it is or isn't reaching the alternator as well will quickly diagnose any future broken wire.
Regarding the broken wire for the field enable, I will solder a new section on to increase the length and also run an additional wire back up to the battery area. This additional wire will be connected to the alternator field enable terminal by a separate ring terminal so it is a separate wire to the original field enable wire. This separate wire is necessary in order to confirm the signal is actually reaching the alternator terminal. The idea is I have an easy way to attach my voltmeter to check the field enable signal without having to do anything other than open the bonnet. This test wire will be cable tied to the new main battery cable from the alternator to keep it away from the driveshafts etc and will simply be cut to length at the battery end and covered in an insulating sleeve that I can remove when I want to monitor the signal. I think it is possible to monitor the field enable signal using multiscan (and maybe other OBD2 diagnostic units) but that just tells you the signal is being generated at the CPU end. Being able to to confirm it is or isn't reaching the alternator as well will quickly diagnose any future broken wire.
You can lead a horse to water.....
Just read this after posting about my intention to run a test connection for this circuit (we were probably typing at the same time). I am grateful to know this is a data circuit and not a simple enable or analogue. I wonder if you could confirm this applies to the earlier version as well? I ask because on the earlier version the terminal is labelled "D+" whereas on the later version it is labelled "LIN". A career as a commissioning engineer has taught me these little details can mean everything.
Hopefully the horse will be able to find the water and decide when and how much to drink without recourse to a situation that results in a master servant relationship. I notice wild horses seem to manage quite well in this regard.
Sorry, not able to confirm earlier type as I was just researching my vehicles issues.
The LIN bus is the slowest of the data busses, on the Fiat, but is reliant on a good/perfect earth path from the alternator to the neg terminal on the battery. By adding an alternative eath cable to my vehicle I solved all charging & start/stop issues. My system sits at 12.7V no matter how many electrical systems I turn on (to create loads). If you research the capabilities of the intelligent alternators you will understand how the manufacturers can lay claim to their eco friendly figures. From not charging at all when not needed, to also not charging under hard acceleration.
PS, ignore the horse comment, I was trying to provoke you into reading my previous comment before you connected 12V to it as a field connection.
Many thanks for your help here. To be honest I was in a state of unconscious incompetence when I started this. I could see from the circuit diagrams that the stop/start sensor on the battery -ve and alternator were both connected to the ECU and as I had a broken wire on the stop/start sensor I guessed that may have something to do with the alternator not charging, though I had no idea how that might work. As it was an easy fix I took care of that before starting on the alternator. It did not help. When I connected my Icarsoft OBD2 unit and monitored the voltage it went up by about 0.5v when I revved the engine but dropped back at tick over and continued to trend downwards as time passed, even with repeated bursts of revving. That is when I made the decision to change the alternator. Thanks to your help when I have got the alternator back in if it is charging I will monitor the voltage over a 30 minute period to see if it varies as a smart alternator would or remains constant. I will post the result so others will know what the situation is with the older alternators. If the alternator is not working I will get out the Multiscan an have a look at the "battery charging" flag (it might be called something else) to check the ECU is happy. For all I know it could be a faulty stop/start sensor.
It is critical that you add an alternative earth path (even if its a good jump lead) when you do your testing.
I too bought an alternator before adequate research, and did all the other stuff, so you're not alone.
Sorry I can't be more helpful right at this moment, as I'm trying to work. Will have more time later.
checkout some of my other posts on this subject, it may help.
I too bought an alternator before adequate research, and did all the other stuff, so you're not alone.
Sorry I can't be more helpful right at this moment, as I'm trying to work. Will have more time later.
checkout some of my other posts on this subject, it may help.
Good job I am retired and this is more of a hobby. My main car is German and very reliable and I have a van for backup. The Fiat is a special case, I bought it for the missus long ago when she was going to give up on her driving lessons. She passed her test and fell in love with it, right up to the point when the drove an automatic for the first time. Now she won't drive a manual at all. I have invested so much in keeping this thing going over the years it is now a hobby in it's own right. 2011 reg and only done 55K. I would never advise anyone to buy this for a main car even though I determined to keep this one going to the twenty year mark.
Ok, have a bit more time now....
Here's the expected communication waveform on the LIN cable when running.
Here's a link to my permanent additional earth cable.... for your perusal.
Another Earth Cable Option
other things I discovered and/or learnt during researching my non-charging problem.
Here's the expected communication waveform on the LIN cable when running.
Here's a link to my permanent additional earth cable.... for your perusal.
Another Earth Cable Option
other things I discovered and/or learnt during researching my non-charging problem.
- If you disconnect the plug on the negative battery terminal, and blip the throttle reasonably hard, you can self energise the field windings and the alternator will act like a normal alternator using the internal voltage regulator. I did actually test this and it works, although not something I would rely on.
- The alternator when working as the manufacturer intended will if you are not using current (or virtually no current) will NOT sit at ~14.6V as per old school alternators, but will sit at 12.7V (least mine is) and hence the potential difference between battery and alternator output will be virtually zero, and hence no current flow, and no load on the engine, hence using no extra fuel.
- When I first got mine working properly (with additional earth cable) I was dubious about the 12.7V, and tested battery voltage prior to a journey, during, and after, I checked with no load, partial loads and full load, never once did it drop below 12.7V, and I did this for two weeks solid.
- According to the web, an intelligent alternator is capable of turning off the charge under hard acceleration to remove any additional load on the engine and therefore giving maximum acceleration. I have no way of testing this, and so cannot confirm.
