kev807

i have an 88 t2 in a gxl and for some reason im getting a voltage drop not at the battery but the interior when i turn on my lights and a/c or heat even i loose alot of voltage its droping to 12.5 vols from 14.4 with everything off i was wondering if anyone has had this problem before and could help me out a bit by the way i bought car with swap done

Aaron Cake

iTrader: (1)

Have the alternator tested. At the same time, check the condition of the power wire (B+ wire) from the alternator to the engine bay fuse panel. Over time, the terminal ends will burn and melt. If the wire is at all questionable, just replace it with a thicker gauge.

kev807

Alernator is brand new the last ones regulater went and overcharged had same problem with old alternator. Its putting out 14.4 volts and I ran an aditional wire straight from alternator to battery like I said it seems to be the interior only affected could it be a ground? I am a mechanic diesel atleast. I've checked everything noew the person who owned the car before me only has the key on wire hooked to the alternator not the one for voltage meter I'm going thru and fixing his rigging (twisted wires and black tape)

kev807

Sorry for the typing I'm on my phone typing this will be better later on ha

Aaron Cake

iTrader: (1)

OK, you need both the wires at the back of the alternator connected. Otherwise the regulator will do weird things.

The interior itself doesn't have a specific ground, but there is a power feed to it. Check the condition of the wire at the cabin side of the 80A main fuse in the engine bay. That 80A fuse itself may be corroded.

kev807

thank you for your help, i havnt figured it out yet but i do know the wire from alternator to fuse is good and i checked voltage earlier today after work, i was getting 13.0 at idle and around 2000 i was at 14.4 with heat and lights everything on but my volt meter in dash was showing below 12 it has me baffled and im pretty good with 12v to

Aaron Cake

iTrader: (1)

Wait...are you relying on the dash voltmeter to make your tests? If so, don't. Use a real voltmeter connected to the lighter socket or other clean 12V source in the cabin.

kev807

no i use a volt meter at the battery for tests and while i drive i notice the in dash volt meter reading low i have never checked voltage inside cabin other then dash mount maybe i should but i can here the fuel pump loose voltage with everything on

Aaron Cake

iTrader: (1)

The fuel pump uses a set of very long and thin set of wires, which will start to drop a lot of voltage with age. Also, if this is a full TII swap, the ECU will drop fuel pump voltage at light load via a dropping resistor.

Don't rely on the dash meter. It is only a general indication of voltage.

kev807

it runs fine i think it is good then i dont have my volt meter at the house its in my box at work so monday ill check it out

alerx7

is there a way to bypass the voltage drop made by the ecu under light loads? cuz in my t2 if i hit the brake i hear the pump lose power or voltage and my idle drops . and if i have the ac or heat and the radio and wipers my cars will die after im coming to a stop and the car neutral
i just order a fd alt to swap in gonna see if it changes anything

cheddarrr

iTrader: (2)

When the previous owner of my 7 had an electric fan hooked up it would draw way too much currend and when I had the lights on they would dim and the brake lights would nearly kill it. So if you have an E-fan installed I'd look there.

Aaron Cake

iTrader: (1)

You don't want to bypass this.

If your idle is dropping, there is an issue with your BAC valve.

LikeThunda

iTrader: (1)

Check your Ground Cables... Forsure..that always Helps

alerx7

where again is this , sorry

Aaron Cake

iTrader: (1)

Open up your copy of the Haynes manual or the FSM (see the FAQ) and turn to the fuel and emissions section. About halfway through, under idle control, you will find it.

Long story short, it is on the turbo side of the intake manifold. Looks like a cylinder with a single air hose connection and two coolant lines. There is one electrical connection.