You could come up with many scenarios but grounding the stud going to the starter/battery might be the most spectacular and damaging. Has the charging system on this car ever worked correctly since you bought it? If yes, what has been changed since that point?turns out I have some free towing available with my AAA account - so that seems like a better idea.
Question: is there any way a faulty starter can cause problems for an alternator, either via wiring or hardware failure? For that matter, how many different scenarios could cause a good alternator to go bad in a month?
Hi. Okay, redid the ohm test (on two settings) this time, adding the extra three feet of 12 gauge wire clamp to the one side I left off last time, to balance the load and distance.You could come up with many scenarios but grounding the stud going to the starter/battery might be the most spectacular and damaging. Has the charging system on this car ever worked correctly since you bought it? If yes, what has been changed since that point?
Also, did you ever remeasure the resistance of the wire between the battery and the alternator? I'm hoping that 0.87 ohm was measurement error due to the 20K range.
Considering the PO, Master Mechanic (who owned many X19's) was very concerned about overheating, it's surprising the missing heat shield wasn't replaced.Since we tested everything outside of the alt seven ways from Sunday, I feel confident that the issue is within the alt itself.
If the currently installed alt has the same "bolt pattern" on the long screws that hold the case halves together as a later model 65A Bosch, if the consensus among you and your mechanic is that heat took a toll on this one, you could I think "frontdate" your setup to the same layout as the later cars, where the right side scoop has a mini-scoop to send air thru a flexi duct to the later alt shroud.
R/S inner scoop: https://www.midwest-bayless.com/FIA...er-right-ps-fiat-bertone-x19-1981-88-u85.aspx
Ductwork/hose: https://www.amazon.com/Gates-28088-Pre-Heat-Duct-Hose/dp/B000CRDL66
Hose clamps: generic to fit 1-1/2" to 1-3/4" dia hose
Support bracket for hose above: https://www.midwest-bayless.com/Fia...cket-fiat-bertone-x19-1980-88-wfi-oe-nos.aspx
Alt cooling shroud: https://www.midwest-bayless.com/Fia...at-bertone-x19-1980-88-wbosch-oe-renewed.aspx
What year?Having just changed that scoop in my car, good luck changing it with the engine in the car. I did it while the head was off the car, and it was damn near impossible. I don't see how I would have done it if the head was on the car.
What numbers did you get for resistance this time?Hi. Okay, redid the ohm test (on two settings) this time, adding the extra three feet of 12 gauge wire clamp to the one side I left off last time, to balance the load and distance.
Different numbers now, much lower, so that’s a good thing.
Also, still showing completely no voltage loss between direct battery reading and battery to B+ stud reading.
Finally, at 2k rpm, I’m showing 12.26volts while charging, which was down 25 volts from bare, battery reading of 12.51v
Still too low.
And still no ‘G’ light.
Since the same person did the starter & alternator, I’m leaving it with him for a day next week. He’s suspicious it’s something other than the parts he supplied (although we both agree the starter was shite the day it went in).
By the end of next week, it will hopefully be charging at 13.5v and not draining energy or my wallet.
Didn't I post the results in photograph form? lol. "balance the load" - to me it made sense to make the cables the same length, that's all. doesn't hurt anybody, does it?What numbers did you get for resistance this time?
You don't need to add extra wire to "balance the load", whatever that means. The main thing you want to do is connect the ends of whatever test leads and extension wires together and measure their resistance. You will then take that number and subtract it from your total resistance measurement to get the answer.
It would be worth reviewing the data you have taken with the mechanic as it could help point him in the right direction.
I found this new thread today:
Slow start problem
My ‘78 X1/9 has been slow to crank to start for a long time now, but getting worse lately, especially when the engine is hot. I have been thinking it was because it is not getting used much, and the battery is 6 years old. I finally decided to fit a relay to the starter solenoid to take some...xwebforums.com
The photo will give you some idea what can happen to those big wires between the battery and the alternator.
1974 chassis with 1500cc engine, so I wanted to install the alternator cooling duct and needed a scoop with the extra little port for the duct. So I pulled out the '74 scoop and installed an '87 scoop. Bolts right in, if you can reach the nuts...Having just changed that scoop in my car, good luck changing it with the engine in the car. I did it while the head was off the car, and it was damn near impossible. I don't see how I would have done it if the head was on the car.
I didn’t realize a ‘74 had the ‘scoop’. My ‘master fiat mechanic’ thinks I shouldn’t need any shield or external cooling if there isn’t a catalytic converter. Not quite sure why…1974 chassis with 1500cc engine, so I wanted to install the alternator cooling duct and needed a scoop with the extra little port for the duct. So I pulled out the '74 scoop and installed an '87 scoop. Bolts right in, if you can reach the nuts...
Your car originally had an alternator shield. It would be very easy to fabricate one from sheet metal and insulation.I didn’t realize a ‘74 had the ‘scoop’. My ‘master fiat mechanic’ thinks I shouldn’t need any shield or external cooling if there isn’t a catalytic converter. Not quite sure why…
Thanks. I thought the shield on a ‘74 was indeed the case, but my mechanic/parts seller seems to think it isn’t needed. Two alternator failures in one year. Maybe he’s right? Or not? He’s not the easiest fellow to trade knowledge with, at least for me, as he makes it clear his knowledge is far greater, and therefore, correct.Your car originally had an alternator shield. It would be very easy to fabricate one from sheet metal and insulation.
You have a scoop but it is not the one used later with the alternator cooling hose.
I learned there's a carb fan! I've got a 128 not an X.. I guess we don't rate a carb fan!So there’s a temp sensor for the carb fan - you learn something everyday. I’m assuming it’s easy to find in the 300-page service manual? No chance the carb is running hot?
Did you like those resistance numbers better, as seen in the photos? Much lower - are those in the ballpark of acceptable (it's all new to me)?Your car originally had an alternator shield. It would be very easy to fabricate one from sheet metal and insulation.
You have a scoop but it is not the one used later with the alternator cooling hose.
I had to download the photo and adjust brightness/contrast to read it. Yes, 0.07 ohms is an improvement. However, that would be over a 4 volt drop if your alternator could ever supply 61 amps to the battery. I forget what gauge the battery/starter wire is but here is the resistance per foot of some common wire sizes:Did you like those resistance numbers better, as seen in the photos? Much lower - are those in the ballpark of acceptable (it's all new to me)?
Measuring sub 1 Ohm resistances without a 4 probe setup isn't all that useful. Alternator to starter is listed as 6 mm^2, and starter to battery is 16 mm^2. Assuming 1.5m of the first, 2 m of the second, that comes out to about 6 mOhms. A pair of 0.5 m 18 AWG probes is 4 times that. Probe tip to wire is something, and a very non-repeatable something at that etc.I had to download the photo and adjust brightness/contrast to read it. Yes, 0.07 ohms is an improvement. However, that would be over a 4 volt drop if your alternator could ever supply 61 amps to the battery. I forget what gauge the battery/starter wire is but here is the resistance per foot of some common wire sizes:
Gauge Ohms/ft.
6 .00040
8 .00064
10 .00102
So, for the sake of argument, let's assume the wire is 10 feet long and is 8 gauge. That would give you 10 x .00064 = .0064 ohms. That is an order of magnitude lower than your last reading. Of course, there is some resistance from the wire to connector interface and resistance between connecters, mounting studs, etc. so the number is not likely to be quite that low.
That's roughly equivalent to #9 and #5 AWG as far as cross sectional area goes. Those are a bit unusual sizes in the US. I suppose they must correspond to something more common in Europe. I wonder if those wire sizes were constant across production or if they increased as the alternator went from 32 amps to 65 amps as the electrical load grew.Measuring sub 1 Ohm resistances without a 4 probe setup isn't all that useful. Alternator to starter is listed as 6 mm^2, and starter to battery is 16 mm^2. Assuming 1.5m of the first, 2 m of the second, that comes out to about 6 mOhms. A pair of 0.5 m 18 AWG probes is 4 times that. Probe tip to wire is something, and a very non-repeatable something at that etc.
Cross section in mm^2 is how wire size is specified in Europe. 6, 10 and 16 are common sizesThat's roughly equivalent to #9 and #5 AWG as far as cross sectional area goes. Those are a bit unusual sizes in the US. I suppose they must correspond to something more common in Europe.