High amp draw - diagnostic assistance - ZR-1 Net Registry Forums

BigIke · 05-14-2018

I've burned up two alternators pretty quickly. After the last install, I put the original pulley on (larger thinking my constant 7000 rpm adventures were killing alts...) but the voltage was very low at idle with AC on.

When The Car is hot and both fans are on high speed, the voltage is low (12vdc)when cold and the AC is on the voltage drop is the same or a little lower.

Amp draw is 15-17 on both fans, and around 20 on the AC blower motor.

Recon I need cooling fan motors or a new blower motor?

The blower doesn't feel like it blows as hard as it once did...

Thanks Jay.

PS. Haven't posted in awhile but I'm still beating the snot out of this thing, and loving every minute!!!

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Young1 · 05-16-2018

Are you sure you are getting 124 amp alternators?

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S.hafsmo · 05-16-2018

You're certain that the battery is in good condition?

BigIke · 05-17-2018

The Alternators are from Jerry, the only way to go IMHO. The Battery is New, but it's done it with two or three different batteries.

I'm putting it on the lift after work to install my Watson Headers and New ZF6.

When i get it running again, i'll write down my current draw for: Fan1, Fan2, AC Blower Motor, and Total Current load. It's got to be something easy.

It only shows low VDC when the coolant temp is high @ idle or when the AC is on @ idle.

Young1 · 05-18-2018

Could it be the bearings in the fans are dry and causing too much friction and a high amp load? It might be worth looking into.

BigIke · 05-18-2018

I have the inner fenders off for header install that has grown to motor mount replacement and header install. I'll take it off tomorrow and spin it. Thanks for the idea!

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05-14-2018	#1
BigIke Join Date: Aug 2014 Location: Montgomery TX Posts: 263	High amp draw - diagnostic assistance I've burned up two alternators pretty quickly. After the last install, I put the original pulley on (larger thinking my constant 7000 rpm adventures were killing alts...) but the voltage was very low at idle with AC on. When The Car is hot and both fans are on high speed, the voltage is low (12vdc)when cold and the AC is on the voltage drop is the same or a little lower. Amp draw is 15-17 on both fans, and around 20 on the AC blower motor. Recon I need cooling fan motors or a new blower motor? The blower doesn't feel like it blows as hard as it once did... Thanks Jay. PS. Haven't posted in awhile but I'm still beating the snot out of this thing, and loving every minute!!! Sent from my SM-G950U using Tapatalk

05-16-2018	#2
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 895	Re: High amp draw - diagnostic assistance Are you sure you are getting 124 amp alternators? Sent from my iPhone using ZR-1 Net Registry __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.

05-16-2018	#3
S.hafsmo Join Date: Nov 2016 Location: Norway Posts: 397	Re: High amp draw - diagnostic assistance You're certain that the battery is in good condition? __________________ - '90 ZR-1

05-17-2018	#4
BigIke Join Date: Aug 2014 Location: Montgomery TX Posts: 263	Re: High amp draw - diagnostic assistance The Alternators are from Jerry, the only way to go IMHO. The Battery is New, but it's done it with two or three different batteries. I'm putting it on the lift after work to install my Watson Headers and New ZF6. When i get it running again, i'll write down my current draw for: Fan1, Fan2, AC Blower Motor, and Total Current load. It's got to be something easy. It only shows low VDC when the coolant temp is high @ idle or when the AC is on @ idle.

05-18-2018	#5
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 895	Re: High amp draw - diagnostic assistance Could it be the bearings in the fans are dry and causing too much friction and a high amp load? It might be worth looking into.