low voltage with quad air booster

[chris c]

car had the quad air booster when i bought it. the booster actually works [headlights get brighter when it builds boost] but i have low voltage at idle and under no boost conditions.

i tested the alternator output and i get 11.88 volts, same across the battery when car is running. i have tested for a draw in the electrical system and have not found one.

doing some reading here is seems the voltage booster should be hooked to the tps and mine is not. actually mine appears to be hooked only to the fuel pump jumper wire.

car was acting same with old alternator so i bought a new one. my wallet is lighter and car still don't work..

 

[TurboDave]

Quad air volt boosters don't use TPS signals and don't hook there. You're reading about a different brand. Quad air volt boosters use boost as a reference, hence the vacuum line tapped to boost out the bottom of the sensor.
Had one quite a few years ago. After it ate three alternators, I decided it wasn't worth the expense to get a few extra volts, and decided hotwire kits were far more reliable.

 

[chris c]

Quad air volt boosters don't use TPS signals and don't hook there. You're reading about a different brand. Quad air volt boosters use boost as a reference, hence the vacuum line tapped to boost out the bottom of the sensor.
Had one quite a few years ago. After it ate three alternators, I decided it wasn't worth the expense to get a few extra volts, and decided hotwire kits were far more reliable.

your explanation makes this booster look right now. i was getting confused reading and didn't know if mine was hooked up wrong.

looking at it that is what i thought. used boost as signal and also sends power to fuel pump through the jumper. makes sense.

but why the low voltage with a new alternator?

anyway i am all for ditching the booster for a hotwire kit but i think i'll still have low voltage. something else must be wrong...

 

[mikestertwo]

Remove the booster and put wiring back to stock. Then take a voltage reading. I assume you have the stock crank pulley on the motor. Are you taking the voltage readings at idle? Do the volts go up when you bring the rpm's up?

 

[TurboDave]

Remove the booster and put wiring back to stock. Then take a voltage reading. I assume you have the stock crank pulley on the motor. Are you taking the voltage readings at idle? Do the volts go up when you bring the rpm's up?

I agree. My bet is, once removed, and assuming the wiring can be put back in good working order, your voltage should come back to normal.
Any alternator in good working order on our cars should read 14.2-14.4v at the back lug, during idle.

 

[chris c]

figured out the problem. the brown wire going to the voltage booster is not hot. none of the wires coming out of the booster going to the alternator had power and i back tracked that to the brown wire. if i jump the brown wire i get 14.2 out of the alternator...

now to figure out where the brown wire is losing power...

 

[chris c]

haven't figured out a fix...

the charging is no consistent. maybe the volt booster is bad? how do i put it back to stock? what wire goes where?

 

[David65]

haven't figured out a fix...

the charging is no consistent. maybe the volt booster is bad? how do i put it back to stock? what wire goes where?

To put it back to stock, there should be a brown wire coming out of the loom near the bottom of the alternator. That brown wire needs to go in the L (lamp) position in the 4 pin regulator plug on the back of the alternator. That is the only one of the 4 that is used as it was originally. If you can't read the letters, I think they go in the order P, L, F, S, with S being the bigger of the 4. To check the circuit, ground the brown wire to something (alternator case) and turn the ignition switch to run, don't start the motor. The alternator light on the dash should come on. If it doesn't there is an open in the lamp lead circuit somewhere. The way the circuit works is one side of the dash light is tied to +12V through the ignition switch and a fuse. The other side of the light goes to the L terminal of the regulator. If there is a problem with the regulator or there is no rotation while the ignition is on, the regulator pulls the L terminal to ground to complete the circuit and turn on the dash light.

David