customblackbird

iTrader: (2)

I just had to send my speed hut quad gauge back as I had some delaminating to the gauge face below the volt meter. There tech said that its due to overheating of the volt gauge from high charging or pegging the needle. I remember that my gauge would peg once in a while and wouldn't go back to normal till I shut down and restarted the gauges. While the gauge was pegged I verified that my power master 160amp alternator was still providing the correct 14.6v charging even if the gauge was pegged at 18+V. They asked how I had the gauges wired and my stock 87 firebird gauges are wired with key on power which is how I have these all wired. They said it needed to be powered by a ACC power source or something that isn't on while cranking. The gauge didn't do it every time... maybe like 10 times over the course of a few years but I didn't bother restarting it to get it back to normal and would drive like that for the remainder of my trip which was probably 15-30min usually.

So anyways they are sending the gauge back after replacing the gauge face and I get it back this Friday. I'm looking to get the car ready and nows the time to change the wiring. Since the volt gauge pulls power from the gauge power which is daisy chained on the speed huts that means that all my gauges need to be powered the same. I found a ACC wire thats hot in ACC and RUN but not KEY ON (one click clockwise from key off), ACC is counter clockwise one click and run is 2 clicks clockwise from OFF. So now I have to decide if I want to power via the way Ive always had it or do i switch to the ACC power source?

How do you guys normally power these up?

aaronc7

I like to use "RUN + START" source so it powers on when key is on the run position and it does not lose power when cranking. My wideband used to be on an ACC source but then it would reset during cranking and would have to run thru it warmup process again and wouldn't come online right away. This could also cause issues with a boost gauge that takes an ambient pressure reading on startup if it's resetting while cranking.

I just looked at the electrics section of the service manual and scrolled down until I found a good RUN START source that was located in the fuse box that was nearest.

customblackbird

iTrader: (2)

My current switched 12v ignition source has power during cranking I believe. I want to say I see the volt gauge dip to 9.75ish volts during cranking but I could be wrong. my fitech/EFi pcm is hooked to the same source for switched power as it’s right off the ignition switch and I have a full fuse panel to hook everything up to for switched power source. The fitech needs power during cranking otherwise it wouldn’t be able to stay powered to crate spark and have the Fuel pump continue to prime during cranking to start. But I believe this is also my issue as during cranking my WB02 restarts anyways due to the voltage drop and even then it takes like 15s to go through the warmup period.

I found an ACC source but it would do the same thing as before but has no power in crank mode. I just decided to get a 10s delay relay which I will
power off battery power and use my ignition key to activate it. So my gauges will power up on a 10s delay but my WB02/boost gauge and my AEM truboost will turn on as normal unless I want to Hook them into the 10s delay relay which I might do.

aaronc7

I notice my WB will go dead for a couple seconds after a start too but it's only a couple seconds unlike 15+ it was before on açc power.