North American Turbocoupe Organization



Alternator fuse blew.. why?
John B Offline
Member
#1
I have a 130A 3G alternator on the my 88. On Sunday, I was out for a drive and got on it pretty good in 4th right before getting back home. When I left off the throttle, there was a considerable "backfire" and the car seemed to stutter. I limped it back home and started looking around. The car will start fine but will not hold an idle. If I don't give it throttle, it will die immediately. I hooked up the laptop and saw that the alternator wasn't charging. I diagnosed all the wires to the alternator and found that the 200A fuse in the power cable blew. Any idea what would cause this? I'm going to check grounds on the car and also have the battery checked as well. The alternator was working just fine up until that point but I'll probably have it checked too. Any thoughts would be appreciated.
88 Turbo Coupe: Front mount intercooler, MGW short throw shifter, full coilover conversion, tubular control arms front and rear, svo front brakes, vacuum assist brake swap, manual steering swap, GT35R turbo with external gate, pimpx ecu, 60lb injectors, 3 core aluminum radiator, Boport 1.5 cam, gutted upper, corbeau fixed back seats, and the list goes on.
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Jeff K Offline
Administrator
#2
Sounds to me like you must have a direct short to ground in the wire between the alternator and the battery or the alternator has shorted internally. The 130 Amp alternator itself can not blow a 200 A fuse, but a blown (i.e., shorted) diode or diodes in the alternator can pull as many Amps as the battery can supply. A good fully charged battery can supply over 1000 Amps under a direct short, which would instantly blow a 200 Amp fuse.

You could disassemble the alternator to access the diode pack and check eash diode with a DMM. If you have a DMM with a diode test mode, this is easy to do. If you have a DMM without diode test mode, you can do a resistance check on each diode. Resistance should be infinite with one polarity and close to zero ohms in the other direction.

Many parts stores will test an alternator for free. The test will tell you if you have a shorted diode IF the counter person knows what they are doing (good luck with that!)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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John B Offline
Member
#3
Thank you Jeff, I just spoke with PA Performance and I will be sending the alternator back to them for testing. If they do find something wrong, they will fix it under warranty. Nothing in the power cable seems out of the ordinary. Gives me a chance to clean up some of the wiring in that area. I'll report back with what I find out.
88 Turbo Coupe: Front mount intercooler, MGW short throw shifter, full coilover conversion, tubular control arms front and rear, svo front brakes, vacuum assist brake swap, manual steering swap, GT35R turbo with external gate, pimpx ecu, 60lb injectors, 3 core aluminum radiator, Boport 1.5 cam, gutted upper, corbeau fixed back seats, and the list goes on.
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Jeff K Offline
Administrator
#4
Even quality parts can fail. No issues with the PA Performance in the 88 TC in the 16 or so years I have had it. However, back in 2010 my daughter and I went to the Street Machine Nationals about 450 miles south of where we live in my 86 Tbird 5.0 V8. Headed out to get pizza the first night. Crusing at 70 mph on the interstate we heard a shreek and voltmeter went to 12.2 V. Then smoke from under the hood. Coasted down a nearby exit ramp, and popped the hood. Serp belt was shredded and wrapped around the sway bar. PA Performance alternator was seized due to the rear alt bearing coming apart. Called for a tow (thank God for classic car insurance!). Tow driver, who was a Ford guy, took us to an Auto Zone in a nearby town, and used his company discount to get us a replacement 130 A 3G alt and a new serp belt at a steep discount. Replaced alt and belt in the AZ parking lot and made it to the pizza place by 8 PM.

Called PA Performance early the next morning and told them the story. They told me they usually require the defective alts to be shipped back for inspection before shipping a replacement, but in my case they would express ship me a new one if I promised to ship them the failed alt. Wife called to say the new alt arrived at our house the next day. When we got home, I sent the old alt back. They also paid for the shipping to return the old alt. Great customer service!

Now I have a barely used Auto Zone 130A 3G alt in my parts stash if I ever need it.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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John B Offline
Member
#5
I'm glad to hear things turned out alright that evening. I don't have classic car insurance but I do pay for AAA premier just in case I ever need a long distance tow. I can attest to PA Performance's great customer service. Anytime I ever call them, they are very nice and helpful. I will be shipping the alternator out today for them to take a look at it. I will be curious to see if they find anything wrong. I'm hoping so because if it isn't the alternator them the hunt continues for what caused the blown fuse.
88 Turbo Coupe: Front mount intercooler, MGW short throw shifter, full coilover conversion, tubular control arms front and rear, svo front brakes, vacuum assist brake swap, manual steering swap, GT35R turbo with external gate, pimpx ecu, 60lb injectors, 3 core aluminum radiator, Boport 1.5 cam, gutted upper, corbeau fixed back seats, and the list goes on.
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John B Offline
Member
#6
Quick update here; alternator has been sent back to PA Performance. Hopefully will find out if anything is wrong with it tomorrow. Also had the battery checked and it was bad. It is about 6 and a half years old so I’m not surprised. I’ll repost again once I get the alternator back and have the car fired back up.
88 Turbo Coupe: Front mount intercooler, MGW short throw shifter, full coilover conversion, tubular control arms front and rear, svo front brakes, vacuum assist brake swap, manual steering swap, GT35R turbo with external gate, pimpx ecu, 60lb injectors, 3 core aluminum radiator, Boport 1.5 cam, gutted upper, corbeau fixed back seats, and the list goes on.
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John B Offline
Member
#7
Another update; PA Performance looked through the alternator and found a spot on the rectifier gasket that had rubbed through. They rebuilt it under warranty and sent it back to me. Their customer service is one of the best out there. I have a few other things to button up before I get the car back up and running. Should be good to fire back up this weekend
88 Turbo Coupe: Front mount intercooler, MGW short throw shifter, full coilover conversion, tubular control arms front and rear, svo front brakes, vacuum assist brake swap, manual steering swap, GT35R turbo with external gate, pimpx ecu, 60lb injectors, 3 core aluminum radiator, Boport 1.5 cam, gutted upper, corbeau fixed back seats, and the list goes on.
Mikey97D likes this post
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Kuch Offline
Senior Member
#8
You are not the first to mention that PA's customer service is top notch. Glad they found a problem and are getting it back to you.
1988 Turbo Coupe, Black/Black, 5 Speed, Moonroof,  T3/T4 50 trim, ported E6, 255LPH, Kirban, 3" DP dual 2.5" w Hooker Maxflows, MGW shifter, K&N, Gillis valve, RR cam, Koni's
1964 Ford Galaxie 500XL, 390 6V, Big Solid cam, Headers,3.89's, 4 Speed, Vast and fast
1960 Ford Starliner, 292 Y Block, 312 4bbl intake, headers, 3 Speed, slow and low
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