random_idiot19

Okay, so I'm new here, first time and everything so I need some help guys.

First off, I'm having a serious problem w/ my power. I'm watching my Voltage gauge and whenever I press my brakes it starts to drop from 14 down to 12. Then I watch the backlight of my speedometer dim a little. Happens everytime I press the brakes.

Second problem is when I press the brakes my RPM's start to drop. Of course this is usually occurent (or at least I notice it) when I'm stopped. My RPM's usually idle around 800 till I press the brake, then it starts to idle around 500-400. Then engine then starts to cough like it's about to die. About a second or two later the RPM's go back to regular idling speed of 800 then drop again. This continues till I take my foot off the brake. If my foot is not on the brake then it usually drops to arond 600 then back up to 800. Someone told me this could be a vacuume leak (not sure what that is).

Can anyone help me out w/ this? It's very annoying because I'm afraid my car is just going to die on me one of these days because of this. Thanks a lot guys n' gals!

Alex6969

have your alternator and battery tested

Icemark

anything under 12.5 volts and your alternator is not putting out enough juice to run the car and you are using battery power to keep it running.

You have a bad alternator or bad connections for the alternator.

SpiffyD

well just hope your on the freeway at night and all your lights dim out on you and you start braking and when you brake all the lights shut off for the backlights cuz it draws to much current then your car dies completely out on you. thats what happened to me cuz i had a bad alternator

20B10AE

iTrader: (14)

Hey Ice, I've heard that if you have disconnected your idiot lights completely that the alternator doesn't start charging the battery until after 2500 RPMs or so due to the check alt light being in series (or something like that). Is there any truth in that?

It may be coincidence, but since I pulled the cluster out to add my aftermarket gauges there, I've been going through batteries.

Thanks!

Reese

Icemark

Only if the alt is mis-wired and it is a S5.

See if the reference and run leads are mixed up (the two small wires coming off the alt).

See on the S5 models, the run lead is wired to the clock/warning panel can report a alt failure. Well when the run and reference leads are mixed up, the alts internal regulator is only getting voltage from the clock warning panel (which if dissconnected would not provide any referance).

20B10AE

iTrader: (14)

Ah. this is on an 88 TII with a 20B swapped in. Can I assume that the wiring for the leads would be the same as the S5 and FD alts?

Icemark

You can't assume colors would be the same, however there should still be two small gauge wires coming off the back of the alt.

One will have 12+ volts on it when the engine is running, and ground when the engine is on, but not running with the CPU unplugged. This is the wire that will be running to the CPU (body computer) on a 88.

The other should have either ignition or 12 volts going into the alt.

There should be no wires even running close to the clock/warning panel on the 88 models.

20B10AE

iTrader: (14)

So basicly, my problem is something else. I'll double check grounds, etc again. Thanks for the help!

Reese