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I recently installed the 69 Series NVU gauges in my 67 Camaro. I really like the look and functionality of them. Knowing the exact voltage, water temperature, oil pressure etc.. is what I was looking for and they work well. I am having problems getting the water temperature, fuel gauge, and speedometer to read more accurately though. The speedometer at lower speeds (below 45 mph is up to 5 mph off), but above that is spot on at freeway speeds. The temperature gauge is installed in the drivers side head (I have Dart aluminum heads if that makes a difference), and the Sniper temperature sensor I have installed in the intake manifold. At 200 degrees and below the Sniper and my NVU gauge read exactly the same but above 200 at the hottest I've let the car get the Sniper will read 217 and the NVU gauge will read 230 degrees. I bought a heat gun and verified that the Sniper is the gauge reading accurately. My fuel gauge, when the tank is full, bounces all over the place. It isn't until the fuel gets to around 1/2 tank that the gauge stops jumping around and sits still like it should. I also can't get it to read accurately. It reads over full at full tank and runs out of gas at 1/8 tank. I've had 2 different shops that specialize in this kind of installation and neither can figure it out. Does any one have any experience with these issues? I'm ok with the speedometer being off but it would be nice if it were accurate. The stock one worked perfectly. The analog water temperature gauge worked perfectly too that I had installed previously. I've tried reaching out to NVU but have never been able to contact them. I always get their answering machine and leave a message to have them call back which they have never done. I would never recommend buying NVU gauges to anyone based solely on their customer support. It is non existent. I would've bought Dakota Digital but at the time they didn't offer the Vintage look I was after.
 

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Make sure everything is very well grounded including the gauges. Poor grounding of the gauges could possibly lead to what you are seeing. There may be a ground differential.

Don
 

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^^^, this and also what gauge wire did you run to the gauges for signal?

To big of a wire gauge adds resistance which may affect gauge reading. I am installing AutoMeter gauges and their instructions say use 18 gauge wire for the signal wires
 

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I'm not sure what size wire was used, I had them professionally installed. How can a wrong size wire affect speedometer readings only at low speeds? Or fuel gauge to only be erratic with a full tank? Tach. Oil, voltage are all perfect.
 

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Quality wire has its AWG printed on the wire....can you read it on the wire going to any of your senders for gauges? (10. 12, 14, 16, 18, etc)

To heavy a gauge of wire adds more resistance than the sender was designed to work with thus affecting readings

Since you did not do the installation and know what wire or how grounded....I suggest you discuss this with your "professional" installer..

....or your gauges could be...well not good.
 

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The installer does this for a living. Only auto electrical. He has reached out to NVU to no avail either. He has only installed Dakota Digital before though and has never had an issue he couldn't resolve.
 

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Now that you mention the gauge issue. The only problem I'm having is with 1 gauge. Not the other. I'm going to keep trying to contact NVU. Someday they'll answer!
 

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if its the gas gauge that is wonky....IIRC they need to be calibrated per vehicle. My friend just put one in and he had to adjust it, IIRC, by turning a screw on the back of the gauge until the needle pointed to full when he had a full tank.

IDK about how the NVU gauge is.....likely install instructions came with them if you have them that would say how to adjust the fuel gauge

The temp senders in head will read hotter than manifold but it typically is the most accurate source of what the water temp really is...in the heads which is the hottest it will be in a engine.

speedo....IDK but the gear in tranny needs to be right. IDK if the NVU ones require different gears but they shouldn't. If speedo was right with stock gauge you have the right gear in tranny
 

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Discussion Starter #9
These particular gauges have no adjustment. NVU says their newer model does
 

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To heavy a gauge of wire adds more resistance than the sender was designed to work with thus affecting readings
I respectfully disagree. This is not correct. It is the exact opposite. Larger wire has less resistance.

Furthermore gauges don’t use a lot of current and should be largely unaffected by wire gauge unless it is very small diameter wire used with the fuel sender.

Don
 
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Fuel gauge issue is most likely a sender grounding issue. At least that is where I would look.

Are all the body etc ground straps installed?

Don
 

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I respectfully disagree. This is not correct. It is the exact opposite. Larger wire has less resistance.

Don
My bad...I had it backwards (note to self...post AFTER coffee :). But was trying to convey wire size could be affecting the signal being sent by sender.


Assuming wiring is correct, including solid grounds, than either the sender or gauge is corrupt. To much Teflon tape or thread sealer on senders can cause problems with the sender grounding. Yes typically the senders say to use Teflon tape on threads.....but one does not want to much
 

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Your NVU experience matches mine pretty well. I didn’t get in the weeds with the temp gauge but my fuel garage was a joke. The sender will control where on the gauge it falls but the bouncing is from having no suppression like a stock gauge. The gauge reacts as soon as the sender moves.

I had to call NVU for setting up the speedo with my LS3 swap. Guy was rude and told me that my new GMPP ECU was junk. I ended up figuring it out and ECU was fine. Also they shipped the wrong resister value. And of course the guy told me I didn’t know how to use a multimeter. Got the right value resister and all fixed, I think that was with the tach.

Bottom line is NVU looks cool but they’re junk and support was no where to be found.
 

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This thread is perfect timing for me. I'm experiencing the fuel gauge bounce ( NVU gauges) now as well with my LS Swap. Grounds are secure and I know I have enough of them LOL. I would think the ECM controls the speedo ?
 

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This thread is perfect timing for me. I'm experiencing the fuel gauge bounce ( NVU gauges) now as well with my LS Swap. Grounds are secure and I know I have enough of them LOL. I would think the ECM controls the speedo ?
I would conclude the fuel gage issue is gauge/sender quality related.

No ECM here. SBC with Sniper EFI. Op didn’t indicate mechanical or electric speedometer.
 
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This thread is perfect timing for me. I'm experiencing the fuel gauge bounce ( NVU gauges) now as well with my LS Swap. Grounds are secure and I know I have enough of them LOL. I would think the ECM controls the speedo ?
NVU has new gauges out now that supposedly are adjustable that have the identical look of the 69 Series I purchased. I offered to send them my gauges back and upgrade but they wouldn't offer me any credit whatsoever for my old gauges. I would've had to pay full price again. The guy who installed the gauges has another idea he's going to try next weekend. If it works I'll post back an update
 

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Discussion Starter #17
I would conclude the fuel gage issue is gauge/sender quality related.

No ECM here. SBC with Sniper EFI. Op didn’t indicate mechanical or electric speedometer.
I have the NVU 69 series gauges which are electrically driven.
 

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I'm using a Classic Instruments fuel sending unit, they are pretty good quality. As mentioned, the quality of the fuel gauge is questionable.
 

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What transmission. And what are you using for VSS?
 

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If it were me I would try putting a large capacitor to ground on the fuel sender line. My initial value would be several hundred to several thousand uF and would go from there. No guarantees it would work but it’s worth a shot....

Capacitor voltage rating should be 18 volts or greater. Minus terminal to ground. Plus to sender line.

Don
 
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