possible short

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Hello all, i've got a bit of an odd problem, i think it may be an electrical short but im not sure.  I was driving yesterday and mid drive i noticed my engine stumbling, radio cutting out and gauges jumping

It took me a min to figure out it was whenever i stepped on the brake, also the (amp meter?) was reading almost to the far right side all the time and would drop when braking.  

I stopped and checked the fuses, they seemed fine, but the problem continued then suddenly mid drive it went away.  i'm going to try get a gauge so i can check them properly

but besides that any ideas on something else i could check? or should i wait for it to recur?

Car is an 88 Formula

Thanks guys!!

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Mumbles Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 30 August 2011 Status: Offline Points: 13	Post Options Post Reply Quote Mumbles Report Post Quote Reply Topic: possible short Posted: 30 August 2011 at 7:12pm
	Hello all, i've got a bit of an odd problem, i think it may be an electrical short but im not sure. I was driving yesterday and mid drive i noticed my engine stumbling, radio cutting out and gauges jumping It took me a min to figure out it was whenever i stepped on the brake, also the (amp meter?) was reading almost to the far right side all the time and would drop when braking. I stopped and checked the fuses, they seemed fine, but the problem continued then suddenly mid drive it went away. i'm going to try get a gauge so i can check them properly but besides that any ideas on something else i could check? or should i wait for it to recur? Car is an 88 Formula Thanks guys!!

Dawg Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 15 August 2009 Location: Canada Status: Offline Points: 988	Post Options Post Reply Quote Dawg Report Post Quote Reply Posted: 30 August 2011 at 10:56pm
	Hey mumbles, welcome to the group. When you step on the brake pedal, a fair amount of current goes to the tail lights. I suspect you have a very bad connection somewhere that heats up too much when you apply the brakes. This "eats up" all the voltage going to the devices that are effected. Somewhere you have a corroded power connection. Look at the wiring diagram for a power path that supplies the items you listed. Then look for a bad connection. Don't forget to check the ground connections too if the positive side is all good. Cheers, Dawg
	You dream it up....I'll make it

CFoss Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 13 February 2007 Location: Canada Status: Offline Points: 580	Post Options Post Reply Quote CFoss Report Post Quote Reply Posted: 31 August 2011 at 2:44pm
	Mine acted this way when I lost the field connection to my altenator. What happens is that when a load is applied, the altenator cannot produce more energy and then there is a downward spike in voltage which messes everything up including the ignition system. Look at the small wires going to the alt for condition. They connect to the field. You could try: Get a helper; connect a voltmeter across the battery, rev to 2krpm and hold, then get the helper to step on the brake. Notice a decent drop in the voltage (1 or more volts)? Also, the same thing can happen if the alt belt is really loose. Chay
	86 SE 3.4

Capt Fiero Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Founding Member Joined: 12 February 2007 Location: Canada Status: Offline Points: 4039	Post Options Post Reply Quote Capt Fiero Report Post Quote Reply Posted: 31 August 2011 at 7:59pm
	Check the Positive cable that goes from the battery to the starter, on occasion it will rub around the battery box, or on the rear manifold. In the beginning it will just barley arc depending on engine load and how far the engine is leaning over from torque. It will be just enough to cause the alternator to spike when it recovers or drop really low when it arc's. Its a 2 second thing to check, so I usually start with that, then work my way into the harder tests.
	Capt Fiero 88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd.

Mumbles Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 30 August 2011 Status: Offline Points: 13	Post Options Post Reply Quote Mumbles Report Post Quote Reply Posted: 31 August 2011 at 8:15pm
	Thanks for all the suggestions guys, I'll start trying to rule things out tomorrow :)

Mumbles Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 30 August 2011 Status: Offline Points: 13	Post Options Post Reply Quote Mumbles Report Post Quote Reply Posted: 08 September 2011 at 11:05pm
	Capt Fiero was right on the money!! Thanks again for all the suggestions guys.

Capt Fiero Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Founding Member Joined: 12 February 2007 Location: Canada Status: Offline Points: 4039	Post Options Post Reply Quote Capt Fiero Report Post Quote Reply Posted: 09 September 2011 at 4:39am
	Glad to have helped out.
	Capt Fiero 88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd.