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Taurus fan mod now low voltage?

C

chadmjohn

NAXJA Forum User
Location
Charlotte, NC
So I just completed the taurus fan swap and all went well. I removed the fan pully and cut the housing as recommended on go-jeep. The installation went well and all is working fine but now I have low voltage, about 13.6V. This came on immediately after the mod so I don't think the alternator suddenly went bad. all wiring is the same and was not affected by the installation of the fan. the voltage is the same regardless of the devices running, radio, fan(s), AC compressor etc.

I have checked and adjusted the belt tension, I have no squeal but the voltage has not changed. I plan on taking the alternator in for a checkup but was wondering if this is a 'regular' problem with this mod? Is it possible that there is no longer enough belt wrap on the alternator pulley now that the fan pulley is out of the best scheme?
 
Im not sure what year your jeep is but some of the earlier jeeps only came with 90A alternators. Maybe the fan is drawing too many amps for you alt. (im not sure how many amps the fan draws)?????:eyes:
 
Taurus fans seem to be high-current devices. Therefore, they'd pull your current down a bit.

However, is that 13.6VDC with the fan running? If it is, that's just fine - 13.0VDC is minimum spec with the engine running anyhow, with 13.6VDC being preferred. So, your "low voltage" may be relative to what you normally have, but it's not actually "low."

I'm going to assume that 13.6VDC is reading with a DMM, yes? After all, the IP meter just doesn't resolve that fine...
 
Sorry, I should have put that in, it's a 97. I don't think it's the fan though as I still have low voltage even when the fan is not running. I have also checked for small shorts, frayed/scraped wires etc and there are none to be found.

xSUx SGT BAKER said:
Im not sure what year your jeep is but some of the earlier jeeps only came with 90A alternators. Maybe the fan is drawing too many amps for you alt. (im not sure how many amps the fan draws)?????:eyes:
Click to expand...
 
Yeah, DMM. I just think it was quite odd that I would lose about 1 volt just from the mod. With all other things being the same (that I have found) it seems as though the alternator may not have enough belt wrap, but that is just me guessing.

5-90 said:
Taurus fans seem to be high-current devices. Therefore, they'd pull your current down a bit.

However, is that 13.6VDC with the fan running? If it is, that's just fine - 13.0VDC is minimum spec with the engine running anyhow, with 13.6VDC being preferred. So, your "low voltage" may be relative to what you normally have, but it's not actually "low."

I'm going to assume that 13.6VDC is reading with a DMM, yes? After all, the IP meter just doesn't resolve that fine...
Click to expand...
 
chadmjohn said:
Sorry, I should have put that in, it's a 97. I don't think it's the fan though as I still have low voltage even when the fan is not running. I have also checked for small shorts, frayed/scraped wires etc and there are none to be found.
Click to expand...

You should have given with your year (97s have alternators that are rated for a bit over 100A,) but what I said earlier still stands - having 13.6VDC is not "low" voltage - that's right where you want to be.

Nominal Voltage Readings:

12.6VDC (12.0-12.6) - At Battery, Engine OFF
09.6VDC (09.6-10.2) - At Battery, Engine CRANKING
13.6VDC (13.0-14.5) - At Battery, Engine RUNNING

You can then backtrace along the alternator circuit if you're getting low voltage there (between "spec" and EO battery voltage usually means a dirty/corroded connection somewhere,) but you're still fine. 13.6VDC is right about where you really want to be - much over 14.5 for very long, and you'll cook your battery. Below 13.0, and you'll end up running off of your battery (and draining it) in rather short order.
 
chadmjohn said:
Yeah, DMM. I just think it was quite odd that I would lose about 1 volt just from the mod. With all other things being the same (that I have found) it seems as though the alternator may not have enough belt wrap, but that is just me guessing.
Click to expand...

Hey Chad,

1) Yes, the Taurus fans draw a lot of amps. On the low fan setting, I can only have the a/c /heater blower on 3 while idling. The volts are right about 13.5. It drops to below 13v if I turn the blower up to 4.

If I run the fan on High, the volts drop below 12.6 while idling without the heater blower on.

Soooo, I can have can can the fan on high with the a/c on max only if I drive above 15mph.

2) You're right. You probably don't have enough belt wrap. No matter how many times I tried, according to GoJeep, I could not get enough belt wrap. I ended up doing some major chopping and moved the radiator forward about 2".

I hope this helps.

E
 
going to do this mod soon! well see how it works for me.
 
I had the same problem of not having enough belt wrap around the alternator. I fabbed up a bracket to go between the alternator and the a/c comprssor and added an idler pulley to give the alternator more belt wrap. Works excellent. It might help in your situation.
 
dbperformance96 said:
I had the same problem of not having enough belt wrap around the alternator. I fabbed up a bracket to go between the alternator and the a/c comprssor and added an idler pulley to give the alternator more belt wrap. Works excellent. It might help in your situation.
Click to expand...

Can you post pics and specs??

E
 
Elias said:
Can you post pics and specs??

E
Click to expand...

If I get down to the shop tonight I will try to snap a couple pics.....
 
Elias said:
Hey Chad,

1) Yes, the Taurus fans draw a lot of amps. On the low fan setting, I can only have the a/c /heater blower on 3 while idling. The volts are right about 13.5. It drops to below 13v if I turn the blower up to 4.

If I run the fan on High, the volts drop below 12.6 while idling without the heater blower on.

Soooo, I can have can can the fan on high with the a/c on max only if I drive above 15mph.
Click to expand...

That's to be expected. Alternators are typically only good for 30-40% of max rated output at idle, unless you've done something to overdrive the thing (or you've installed an uprated alternator - that's simple maths. 30% of 120A is more than 30% of 80A...)
 
Get the biggest alternator you can get with the taurus fan upgrade!! Those fans kick, but they suck juice, as people have said.
 
i hope that i will be fine. i already have a ZJ alt (136 A) and will be adding a Taurus fan shortly.
 
I'll add my .02, I have this upgrade, GoJeeps taurus fan upgrade, ZJ 136 amp alternator, 5-90's full mains upgrade, and I notice a drop in voltage too. However not enough to concern me. I almost never have to use HI on the fan, and no problems on lo. I would trust 5-90 on this, as long as your between his specs I wouldn't worry about it. Btw, I am adding a second battery for emergency jumping but just cause it was free.
 
Been running now for three years with the less rap and never had a problem with it. Still stock alternator.
 
Me neither Marcus, and Jon you're right, with my 136 amp ZJ alternator I checked tonight and idling with no fan on I'm sitting at 13.98 with my dmm. thanks Marcus and Jon.
 
Elias said:
Can you post pics and specs??

E
Click to expand...

508706852112_0_SM.jpg


224506852112_0_SM.jpg


I used 2" angle iron for the bracket. It's a little tricky because you have to work around the existing bracketry. A little trimming here and there and all is good. I used the same idler pulley that the Jeep already has. You will have to get a longer belt though. If I can help any further please let me know.

Sean
 
Thanks for the responses everyone. My main concern was not the amount of voltage so much as the loss of voltage after the conversion. Without the fan running (either the stock or new fans) and without the AC compressor on I lost just under a volt. I was attributing this to belt slip on the alternator pulley.

While the voltage I have now is sufficient and in spec it is definitely lower than what I had before the conversion.

I guess that since I will be upgrading the charging and ground wires soon this is a moot point until then. It could all just be due to the fact that I moved around the battery connections and maybe since they are this old are a bit worn, corroded etc.
 
Dont 97+'s use a different pulley system? Where the belt tightness is not adjustable its tightened by a tensoner? Or is that later years?

I wouldnt be suprised if the belt was tightened with a tensoner pulley that belt wrap is what is causing the issue.

I guess its also possible that you bumped a ground or something causing a weak connection somewhere. Or maybe your right... your mains are just old and ned to be replaced.


FWIW here is some pics of my install:

http://www.naxja.org/forum/showpost.php?p=243943406&postcount=30

Some pics are also on go-jeeps site.
 
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