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Discussion Starter · #1 ·
Hey everyone, I thought I had this problem solved- but it's not. I
installed a 130 amp alternator off a discoII a while ago. I had it
tested prior to installing it, and again once it was installed. The
guy said it works great. Ever since I hooked it up It's been
stumbling and surging from 2000- 3200 rpm to the point that it's not
safe to drive. So, I start replacing everything electrical (plugs,
wires, cap, rotor, stepper motor, fuel injection relays) as well
check all the wires for corrosion. I noticed that the wires that came
with the electric fans were looking fried around the relay for it. So I unhooked it and it runs perfect. Run all new 8 gauge wiring for the
fan and when I hook it back up It runs like **** again. I figured the
problem was the wiring grounding out on the body of the truck. So I'm
wondering why this would happen only when the fans are running? Is it
pulling power from the ignition to run the fans? Remember I had it
tested and was told all is well. Someone suggested I need a dual
battery setup- but this alternator is only putting out 30 more amps
than stock. Do you think that the problem is running the fans from
the battery- and not from the fusebox under the hood. The new
position of the alternator is close to the distributer- could that be
a problem? I'm getting really tired of this ****. Every electrical
shop I talk to is absolutely no help.
Brian Bertolini
 

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Premium Member
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23 Posts
I run a 1000 amp battery in mine and electric fans with a 90 amp allternator, not to mention the amps for the radio. No problems here. Have you tested the battery under load? Put a voltmeter(digital) on it and drive it, when it starts to cut out or run bad look and see what the voltage is doing. When you say it runs like crap. do you mean no power, cuts in and out?
Todd
 

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Premium Member
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152 Posts
Discussion Starter · #3 ·
When I reconnected the fans again -it began to surge and stutter between 2000-3200rpms. Just as it had done before. The only variable I'm looking at here is the alternator- but It has been tested and is supposidly perfect. I had the fans wired previously with my old alternator which died. I had no problem with the fans back then.
 

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Premium Member
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4,789 Posts
THe High output alternators can put out some nasty RF that screws with the ECU. Try connecting the Fans directly to the altinator and not to the battery.
 
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