Carburetor fan possibly drains battery below 12v - ever happen to anyone else?
- Thread starter tvmaster
- Start date
tvmaster
True Classic
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?
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?
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dllubin
Don
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.
tvmaster
True Classic
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.
Dan Sarandrea (Phila)
Waitin' On Parts...
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
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
tvmaster
True Classic
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.
I'm setting myself up for him to find some OTHER problem than the parts which were installed, based on his comment about my wiring tests, which, based on some of the other things I've found the PO electrified (?) could be reality:
"The amount of ground required to turn on a small lamp and the amount of ground to excite an alternator are not equal. Grounding out the wire to turn on a lamp is a good diagnostic tool but nowhere near a complete diagnostic"
Although there is an element of truth there, I think I can read between the lines where this is heading
$$$
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SuperTopo
True Classic
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.
tvmaster
True Classic
What year?
dllubin
Don
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.
tvmaster
True Classic
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?
That photo of the nasty connection - did it say that was his starter connection? I can't get in to look at my starter connection. But I'll bring it up at the day of reckoning next week. The connections at battery terminals, firewall, D+ and B+ seem solid, and it appears the engine to frame ground underneath is good, but that's another one for a closer inspection on a lift or jacks.
I will be taking all my numbers to him, although, as you read, he has his own opinion on how grounding tests are performed
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SuperTopo
True Classic
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...
tvmaster
True Classic
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…
dllubin
Don
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.
tvmaster
True Classic
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.
Maybe by alternator three we‘ll have it sorted….
Lowtechprime
Retro Grouch
I learned there's a carb fan! I've got a 128 not an X.. I guess we don't rate a carb fan!
tvmaster
True Classic
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)?
dllubin
Don
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.
ng_randolph
Bjorn H
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.
dllubin
Don
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.
Yes, a 4 probe setup would be more accurate. Another approach would be to force a reasonable amount of current through it and measure a larger voltage to make the errors less significant.
ng_randolph
Bjorn H
Cross section in mm^2 is how wire size is specified in Europe. 6, 10 and 16 are common sizes