Alternator Question?

MY 85 GT · Aug 16, 2013

I have the crappy stock Alt in the car just installed an electric fan.now its even worse..My question how bad will this effect my ignition meaning weak spark..I had the car out checking the water temp with a new gauge and at one point i got on it and it bogged/popped...to me felt like spark blow out Im thinking...very weak spark being the car never did this with the Fan clutch just now with the Efan im sure it needs an upgraded Alt..im looking inot that now which is better the PA or FROM lATEMODEL RESTROATION THE sve KIT?

stykthyn · Aug 16, 2013

Not sure about weak spark but it is going to kill your battery in no time which could force a shut down while driving( been there and have the t shirt) I have not spec'd out either of the above units. My last three cars all got JY 3g or 6g units.

mikestang63 · Aug 16, 2013

MY 85 GT said:
I have the crappy stock Alt in the car just installed an electric fan.now its even worse..My question how bad will this effect my ignition meaning weak spark..I had the car out checking the water temp with a new gauge and at one point i got on it and it bogged/popped...to me felt like spark blow out Im thinking...very weak spark being the car never did this with the Fan clutch just now with the Efan im sure it needs an upgraded Alt..im looking inot that now which is better the PA or FROM lATEMODEL RESTROATION THE sve KIT?

It is almost painful to read your post and figure out what your problem is.

You are talking about two different parts of the electrical system- primary and secondary. The stock alternator is not sufficient for any e fan IMO and will eventually lead to a weak/dead battery, that can cause problems on the battery/alternator/ starting side. It will not impact the spark as long as the car is running. That is determined by the coil, wires,plugs, distributor, cap, rotor.

I don't know what you mean by the temp gauge bogged/popped as that has nothing to do with spark.

First thing is to install a 130 amp 3G alternator- using the proper wires and fuse.

MY 85 GT · Aug 16, 2013

Sorry about my typing that well im at work did it fast...lol...I meant i installed a new water temp gauge because the Factory one seemed way off which it was...Now why wouldnt a car that has a weak/drawing to much amps not effect Spark??? if the car is supossed to be putting out 14.5 volts and its not say 12.5 i would think the spark is weak?...Especially when im dumping in fuel with 42 lb injectors,a 340 lph fuel pump..etc etc...I think i need a new more powerful Alt...Oh and this never did this when it had a clutch fan on,,,Just now after the electric fan install because the Alt cant keep up....

f8tlfiveo · Aug 16, 2013

3g is needed, the stock unit isn't even big enough for the stock accessories.

stykthyn · Aug 16, 2013

why would injectors and fuel pump make a diff? Not like they are operating at a higher voltage than the stock units. The 75a alternator was insufficient for even the stock parts right from the get go. the car right now is running off the batter since the alternator is not pushing the voltage that your set up requires. This is going to lead to an under charge state which means your battery is going to die. This could lead to a no start issue or when you come up to a stop light and the alternator isnt spinning you car is going to shut down.
Replace witha 125a ro equivalent alternator of your choice and upgrade the wiring and add a 110amp inline fuse.

mikestang63 · Aug 16, 2013

MY 85 GT said:
Sorry about my typing that well im at work did it fast...lol...I meant i installed a new water temp gauge because the Factory one seemed way off which it was...Now why wouldnt a car that has a weak/drawing to much amps not effect Spark??? if the car is supossed to be putting out 14.5 volts and its not say 12.5 i would think the spark is weak?...Especially when im dumping in fuel with 42 lb injectors,a 340 lph fuel pump..etc etc...I think i need a new more powerful Alt...Oh and this never did this when it had a clutch fan on,,,Just now after the electric fan install because the Alt cant keep up....

Again, the temp gauge has nothing to do with the a weak spark.As long as the car is running, the coil multiplies the primary voltage by 100's of times to produces sufficient spark. Why do you think you have a weak spark. Is your car stumbling? What do your injectors and fuel pump have to do with spark. Sorry but you are jumping all over the place.

Either put back on the clutch fan, or upgrade the alternator. The temp gauge not working is probably a bad ground.

MY 85 GT · Aug 16, 2013

I agree 100% thats what im doing looking at the PA kit and the SVE kit as we speak...All i was saying is the stock stuff i dont think can keep up causing my problems right now..Im sure of it...I need a 3g...lol Meaning i dont even think the Electric fan is spinning 100% at idle letting the car run hotter...and i still think its causing weak spark...i dont think the ignition box is seeing the full voltage due to the Alt not keeping up..I heard the stock Alt puts out 20 amps at idle my fan draws 18 amps...lol...so im sure that my problem in a nut shell.

stykthyn · Aug 16, 2013

your better question would be which one of these alternators should I buy?

MY 85 GT · Aug 16, 2013

mikestang63 said:
Again, the temp gauge has nothing to do with the a weak spark.As long as the car is running, the coil multiplies the primary voltage by 100's of times to produces sufficient spark. Why do you think you have a weak spark. Is your car stumbling? What do your injectors and fuel pump have to do with spark. Sorry but you are jumping all over the place.

Either put back on the clutch fan, or upgrade the alternator. The temp gauge not working is probably a bad ground.

No i must be writing it wrong...I install an auto meter gauge because the Factory one was reading screwy so i wanted to have a better water temp gauge..ok the car did stumble/bog...Im thinking weak spark..maybe because the Alt is charging the Battery 100% its not putting out enough...My injectors and fuel pump have nothing to do with it...just meaning my car runs a little on the rich side due to tune because i run a 14 psi and a turbo..so i think the car was loading up and it had a spark blow out due to a weak spark??..better..lol

MY 85 GT · Aug 16, 2013

stykthyn said:
your better question would be which one of these alternators should I buy?

Yes i know which one????...Pa or SVE..money isnt the issue so which one is better?????

mikestang63 · Aug 16, 2013

MY 85 GT said:
I agree 100% thats what im doing looking at the PA kit and the SVE kit as we speak...All i was saying is the stock stuff i dont think can keep up causing my problems right now..Im sure of it...I need a 3g...lol Meaning i dont even think the Electric fan is spinning 100% at idle letting the car run hotter...and i still think its causing weak spark...i dont think the ignition box is seeing the full voltage due to the Alt not keeping up..I heard the stock Alt puts out 20 amps at idle my fan draws 18 amps...lol...so im sure that my problem in a nut shell.

Save yourself some money. Go to any JY and look at any 94-2000 mustang- v6 or GT and grab the alternator. They are the correct 130 amp 3G case. Bring it to Autozone and have them test it. Then either on Ebay or the Corral buy the 3G wire kit for $40- comes with everything you need- wire, fuse, even the bolt for the top of the alt. Only thing you need to do is-run the new 4 gauge power wire, swap your old 2g pulley onto the 3G, grind off a little of the alt bracket for clearance, splice in the new stator wire into the old harness, and add another 4 gauge ground wire from the block to the 2ndary ground behind the battery. Total coast should be less than $100 for the alt, wires, and any connectors, shrink wrap etc. There are many writeups on the install.

mikestang63 · Aug 16, 2013

MY 85 GT said:
No i must be writing it wrong...I install an auto meter gauge because the Factory one was reading screwy so i wanted to have a better water temp gauge..ok the car did stumble/bog...Im thinking weak spark..maybe because the Alt is charging the Battery 100% its not putting out enough...My injectors and fuel pump have nothing to do with it...just meaning my car runs a little on the rich side due to tune because i run a 14 psi and a turbo..so i think the car was loading up and it had a spark blow out due to a weak spark??..better..lol

what are your plugs gapped at. Stock ignition or MSD. what is your timing set at. Do you have a chip? The stumbling issue is most likely not related to this.

MY 85 GT · Aug 16, 2013

I have an crane HI-6s...dont know what plugs are gapped at had a shop install and tune[moates chip] the whole Turbo set-up...like i said last week with the Clutch fan on it didnt ever ever do this ..I installed an E-fan because it was running hot to me...not realizing the factory gauge sucked...plus a day later the water pump went i bet it wasnt spinning that good IE running hotter... so i replaced it...with a new water pump while i had it apart i did the flex-a lite fan...now the Alt cant keep up so thats the next step...lol...

stykthyn · Aug 16, 2013

Mod motor alternators will not fit. 3.8 and 94-5 5.0 mustang. 6 cylinder Taurus works as well.

Rick 91GT · Aug 16, 2013

I switch them over the the higher amp 1 wire Chevy alternators...usually just need a custom spacer for the case on the lower bolt cheaper as well then a standard 3g swap.

Your stock fan/fan clutch setup pulls more cfm then most electric fans...

Sent from my XT907 using Tapatalk 2

MY 85 GT · Aug 16, 2013

Really wow didnt know that i would have kept the fan clutch set up then...lol

mikestang63 · Aug 16, 2013

MY 85 GT said:
Really wow didnt know that i would have kept the fan clutch set up then...lol

The cheaper BM fan is a joke. They sell it also as ProForm, and on the box it says it is only good for like 220 hp. lol
If you want a good E fan, either get a Taurus or MKVII E fan. They will out pull most aftermarket fans and are cheap.

My bad.. it is not all 96-00 GT .but all the Mustang ones having the correct case and clocking.

94-95 - Mustang 5.0
94-00 - Mustang 3.8
94-96 T-bird 3.8 non sc
95-96 - Windstar 3.0
96 - Sable 3.0
93-99 - Taurus 3.0
94-96 - Cougar 3.8 v6

jrichker · Aug 16, 2013

The water temp gauge that shows in increase in temperature as electrical loads increase is a sign of a bad engine to body ground. Turn on the headlights and/or the fan on high and the temp gauge shoots up. That's what happens when you have a bad engine to body ground.

The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.

Any car that has a 3G or high output current alternator needs a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects. The 3G has a 130 amp capacity, so you wire the power side with 4 gauge wire. It stands to reason that the ground side handles just as much current, so it needs to be 4 gauge too.

The picture shows the common ground point for the battery , computer, & extra 3G alternator ground wire as described above in paragraph 2. A screwdriver points to the bolt that is the common ground point.

The battery common ground is a 10 gauge pigtail with the computer ground attached to it.
Picture courtesy timewarped1972

Correct negative battery ground cable.

Alternator Question?

MY 85 GT

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