customblackbird

iTrader: (15)

I just had to send my speed hut quad gauge back as I had some delaminating to the gauge face below the volt meter. Their 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? I believe the stock gauge power is pink/black and thats just a standard 12v switched power source. I ran my own fuse block for all my aftermarket stuff so not to cut into the stock gauge wiring and since I'm LS swapped none of my stock gauges are used.

How do you guys normally power these up?

sofakingdom

iTrader: (1)

Sounds like the one called ACC is what goes to the HVAC.

You need the one that feeds the radio to get the logic you're looking for.

customblackbird

iTrader: (15)

I can try to look for that one, but my radio wiring is all custom as well (apple car play 7" single Din with larger dia speaker wire for added output) with wire feeding off my blue sea fuse panels. Any idea what color that power wire is for the radio? If I remember correctly (years and years ago) it might have been orange but that was for the 12v constant.

84 1LE

iTrader: (9)

Isnt "one click CW from key off" just to unlock the column/shifter? Next is key on, the run.How would the gauges get power if not from key on.Since the ignition (key) goes back to that position after the engine starts.Is power coming straight from the alt after starting? I have my speed hut gauges wired just like stock, but then i dont have a 160 amp alt.Never any issues though.

Drew

iTrader: (58)

The stock wiring pegs the gauge as part of the bulb test feature. If I'm understanding you, they're saying the 'test' for that couple seconds at start is fragging the gauge?

If you want it on only in the run position, you can tie into the heater/fan/etc wiring. Or you can just run off the aux Radio port in the fuse block. Only difference is the Radio will be powered in run or accessory, while the other won't.

Look in the GM Service Manual under power distribution. It'll be the diagram that shows the ignition switch that you want to study.

You could always wire the gauge to a true clean power source with a relay, and use 12v switched power to make/break the circuit. Assuming you want real voltage instead of whatever drop you're getting thru the ignition switch, fused links, C100 etc.

customblackbird

iTrader: (15)

yea I was incorrect. The first click counter clockwise unlocks the column. Next click is power run and next is start. Power is on in run but not on ACC or on in start. Idk why my speed hit gauge pegs tho. My guess is the key goes to run so my fuel pump primes and I wait 2-3s then crank and start and the key returns to the run position. For some reason once in a while the volt gauge pegs max and stays there till
i turn off and reset. My 160amp is just a beefed up small case alt for an fbody. It’s controlled like stock but I use the fitech ultimate LS controller.

customblackbird

iTrader: (15)

my wiring is run like you said (cleanly) I ran switched
12v to a blue sea fuse panel and then use that for all my switched feeds. I ran a 14 gauge from the panel to feel the gauge wiring. So it wasn’t seeing a bulb test or whatever the stock wiring provides.

I personally think the speed hut gauge just glitches on some starts, gets confused and just pegs. I don’t need the gauges to power on in ACC. I was thinking of adding a delay relay that way the gauges don’t power up for a few Sec before power on that way I can crank and do what I need then come on after. Just not sure how they will like being turned on after everything is already running.

84 1LE

iTrader: (9)

How about wiring the positive on the volt gauge straight to the alt.This should give battery voltage until the eng starts.I dont think the alt is producing power while cranking.I could be wrong though.

customblackbird

iTrader: (15)

there is no seperate power on that gauge, it’s a quad gauge so I have voltage, gas level, coolant temp and oil pressure all in one. Each section has its own sensor wire except the voltage which pulls its power directly from the small 3 wire plug that has power, ground and dash lighting for needle lighting.

Also the alternator only has 2 wires, heavy gauge to the battery for charging and a single wire at the plug to arm the exciter I believe which is provided by the fitech ECU. Not sure where I could hook up for signal as the main heavy wire is hot all the time.

84 1LE

iTrader: (9)

Oh, youve got one of those 4 in 1 gauges? Speed hut should've put a buffer on it.They did something like that for my fuel gauge so the pointer didnt react so much with the fuel sloshing around.

Drew

iTrader: (58)

And that's why I said use a relay to make/brake the circuit to a clean (battery/alt) constant power source. Turn the key off, the relay clicks off and disconnects the gauge from the battery. Key on, relay clicks on and connects the gauge to battery. In theory at least.

customblackbird

iTrader: (15)

yea it’s a 4 in 1. Not sure about the buffer honestly. These gauges were purchased back in 2015 and the voltage thing has been going on for 1-2years. Maybe the buffer was a later option? My fuel tank gauge moves around a bit like stock.

customblackbird

iTrader: (15)

I don’t disagree. The problem is using a relay as you stated is the same as running it off of switched power. The relay will just pull power from the battery vs the ignition switch. The problem is the power to the gauge before and then right after cranking (think of it turning on and off and on real quick) with a large voltage drop could be messing with the gauge electronics, and that’s why speed hut is saying pull it off the circuit that juices during cranking. I’m going to wire in 10Sec relay that way I have a delay before power on and no issues.

NINÅ

customblackbird

iTrader: (15)

Thanks guys, got the gauge back from speed hut real fast and have already installed and rewired. I set it up so the 10s time delay relay provides clean battery power to the gauges and uses the switched 12v to activate the relay. So key on = 10s delay and all my speed hut gauges power up. I timed the delay relay and its exactly 10s and I ordered a 5s delay as well incase its too long. My flexalite variable speed fan controller has a built in 5-6s delay that way the fans don't turn on till the engine has been started and it also has a 30s cool down time after key off... both are nice features. My WB02 and truboost EBC will still key on and power up as normal. I won't know how it works "timed wise" till its spring and its warm enough to start it so unfortunately I won't have that info till march/april. However the my normal startup is to key on, I let the pump prime for 3s or so and then crank (aeromotive FPR does not hold pressure with pump off) so I try to get it when its building positive fuel pressure or right after priming when fuel is full in the lines and rails because you can hear it purge air on prime. So if I wait 3s, then crank 1-2s, then it starts 1s or so thats like 5s already used up so 5s later the gauges all come alive. Like I said worst case is I swap it out for the 5s delay relay and let it eat. Not a lot is happening in the first couple of sec once its started anyways and there is no reason why it wouldn't have oil pressure.

I also believe this is a speed hut engineering problem... no reason 2015 tech should have this problem when the stock volt gauge never had this problem and that was 1987 tech lol. I used to look at my FP gauge to know when it built pressure to crank which I won't have anymore so I will just have to go by feel.