Voltage drop on the highway...

HoodStrype · 09-29-2005, 09:55 PM

Hey guys it's me once again...
First of all this Mustang (Is this link crap the Mustangworks.com or a bug on my computer?)has come a long ways since I got it, and now it cuts out and drops voltage. I thought I fixed it by replacing a fusible link (ground of all things) that went bad off the solonoid, and now it does it again. What wires would directly cause this? It can't be more than a couple can can it?

PS: thanks for all you're help in the past, I thought I was good 'til I bought this '89! Possibly an '85 on the way as well, we'll see.

82 GT · 09-29-2005, 10:46 PM

Without more info, it looks like the alternator is bad.
Do you have a means to test it.....or the battery?
I would start there.

~The Jester~ · 09-30-2005, 06:15 AM

Yeah, check the silly stuff first before you dive into the wiring. Belt slipping at higher RPM? Alt good? Voltage reg good?

If it IS a wiring problem, my guess would either be ground or field.

tmoss · 09-30-2005, 07:18 AM

The factory battery neg connection to the aluminum timing cover can experience galvanic corrosion in the threds that you can't see and cause a poor ground - found it it in mine and I switched the ground to the head.

racerboy88 · 09-30-2005, 12:42 PM

replace the alternator if it is stock, upgrade to a 130 amp model. _I'm looking at the powermaster alternators

HoodStrype · 10-06-2005, 12:40 PM

Oh yeah... had the alternator checked...32 amps! No bloody wonder! It looked brand new when I bought the car. It's a Valucraft- anything that says "value" does not belong on my car- 32 amps!!! POS!

Capri306 · 10-06-2005, 01:35 PM

If you have the stock three-wire harness still on there, I would replace that while you're at it, if it were mine. I'm speaking of the connector with the larger, black wires with orange stripes. The connectors in those like to lose tension, and consequently create heat and start fires. New harnesses are available at most parts stores for this reason alone. I got sick of the low output of the stock alternators and converted it to an SN95 style. Never looked back.

HoodStrype · 10-07-2005, 11:44 AM

Yeah I've actually got a friend who had a late 80's model 5.0 T-bird... his alternator caught fire when he got to work one morning, and he worked at the local Ford dealership in the stockroom! Lmao, now that's a good place for it to happen!

09-29-2005, 09:55 PM	#1
HoodStrype Rearview Mirror Haze Join Date: May 1999 Location: Huntsville, Alabama...a.k.a. "HuntsVegas" Posts: 387	Voltage drop on the highway... Hey guys it's me once again... First of all this Mustang (Is this link crap the Mustangworks.com or a bug on my computer?)has come a long ways since I got it, and now it cuts out and drops voltage. I thought I fixed it by replacing a fusible link (ground of all things) that went bad off the solonoid, and now it does it again. What wires would directly cause this? It can't be more than a couple can can it? PS: thanks for all you're help in the past, I thought I was good 'til I bought this '89! Possibly an '85 on the way as well, we'll see. __________________ 93 lx Notch 01 GT ...the epitome of Murphy's Law

09-29-2005, 10:46 PM	#2
82 GT Import Slayer Join Date: May 1999 Posts: 2,241	Re: Voltage drop on the highway... Without more info, it looks like the alternator is bad. Do you have a means to test it.....or the battery? I would start there. __________________ '82 GT 351W (.060)Comp Cams 274* Extreme Energy cam, ported & polished heads w/ 1.94/1.60 valves 10.3:1 flat top pistons,stealth intake, Mallory dizzy,Holley 750dp carb, BBK shorties,Flowmaster exhaust,C-4 with 3700 stall converter, B&M pro shifter,8.8 rear, 4:10's, subframes, electric fan, powermaster alternator, 4 core radiator.

09-30-2005, 06:15 AM	#3
~The Jester~ Rat Killer Join Date: Aug 2002 Location: Cold ass Ohio Posts: 1,143	Re: Voltage drop on the highway... Yeah, check the silly stuff first before you dive into the wiring. Belt slipping at higher RPM? Alt good? Voltage reg good? If it IS a wiring problem, my guess would either be ground or field. __________________ d-Con Racing "Nothing fancy, just 347 inches of RAT POISON!" MICE need not apply.....

09-30-2005, 07:18 AM	#4
tmoss Registered Member Join Date: Mar 2003 Location: Saint Louis, MO Posts: 634	Re: Voltage drop on the highway... The factory battery neg connection to the aluminum timing cover can experience galvanic corrosion in the threds that you can't see and cause a poor ground - found it it in mine and I switched the ground to the head. __________________ Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/

09-30-2005, 12:42 PM	#5
racerboy88 Registered Member Join Date: Sep 2003 Location: British Columbia Posts: 123	Re: Voltage drop on the highway... replace the alternator if it is stock, upgrade to a 130 amp model. _I'm looking at the powermaster alternators __________________ 1990 5.0 LX H/B H-pipe w/ flowmasters, Koni shocks and BBK springs.

10-06-2005, 12:40 PM	#6
HoodStrype Rearview Mirror Haze Join Date: May 1999 Location: Huntsville, Alabama...a.k.a. "HuntsVegas" Posts: 387	Re: Voltage drop on the highway... Oh yeah... had the alternator checked...32 amps! No bloody wonder! It looked brand new when I bought the car. It's a Valucraft- anything that says "value" does not belong on my car- 32 amps!!! POS! __________________ 93 lx Notch 01 GT ...the epitome of Murphy's Law

10-06-2005, 01:35 PM	#7
Capri306 Moderator Join Date: Sep 1998 Location: Grand Rapids, Michigan, USA Posts: 1,001	Re: Voltage drop on the highway... If you have the stock three-wire harness still on there, I would replace that while you're at it, if it were mine. I'm speaking of the connector with the larger, black wires with orange stripes. The connectors in those like to lose tension, and consequently create heat and start fires. New harnesses are available at most parts stores for this reason alone. I got sick of the low output of the stock alternators and converted it to an SN95 style. Never looked back. __________________ Capri306, Moderator The Mustang Works Online 1979 Mercury Capri 1987 5.0L Mustang LX Notchback 1993 5.8L Eddie Bauer Bronco

10-07-2005, 11:44 AM	#8
HoodStrype Rearview Mirror Haze Join Date: May 1999 Location: Huntsville, Alabama...a.k.a. "HuntsVegas" Posts: 387	Re: Voltage drop on the highway... Yeah I've actually got a friend who had a late 80's model 5.0 T-bird... his alternator caught fire when he got to work one morning, and he worked at the local Ford dealership in the stockroom! Lmao, now that's a good place for it to happen! __________________ 93 lx Notch 01 GT ...the epitome of Murphy's Law

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