:likecat:

<p>I really don't want to change gauges because it fits right where I need it, and I don't have anywhere else to put gauges. I could potentially try and fit a different dual oil/water temp gauge there. But I don't know of any other reasonably priced ones.</p>

I didn't mean the same VEI gauge(s), just if you're running a VEI AFR+boost gauge, get an AFR gauge and a boost gauge from other manufacturers, to see if it's the gauge that's FUBAR, or the controller/signal. If your controller can operate another mfg's gauge, that is.

<p>There isn't a controller. Its just a temperature sensor.</p>

<p>Just got an email back from them. So far they have been helpful and have come up with more things to test. I'm not dismissing them just yet, especially with how helpful they have been.&nbsp;</p>

I had VEI gauges back in 11/12 time frame. They never really worked correctly or how I expected them to. Lots of times they would get stuck reading about half of the temps I was measuring. Oil would read right, and water temps were about half, then would randomly reverse. I honestly ended up just pulling them from the car and have not messed with them since.

<p>I plan to go completely overboard one of these days. Run dedicated grounds from the gauge to the engine block. And from each sensor to the same place on the engine block. Then use a small up/down voltage regulator to give the gauge 12v at all times. If this doesn't work I will find another solution.</p>

I'm curious as to what process they are running you though in an attempt to troubleshoot this.

<p>They had me run an extra ground wire from the engine to a battery ground. And next they're having me ground the sensor to the block better. Even though the sensor body is screwed into the head. I'll humor them though.</p>

My guess is the gauges are on the same ground plane as some of the noisy electronics of your car (such as ignition coils, fuel injectors, fans)

Here's what I would try.

1. Run a new wire from the actual ENGINE BLOCK to be your new ground wire for the gauges, unhook whatever it's currently using. See if this remedies your problem or changes the behavior.

2. Run a fused wire from the battery (or use starter post) to the gauges so they have their own source of clean power, not shared by anything else.

3. Rewire between the gauge and the sensor using shielded cable. On the sensor end, leave the shield unhooked. On the Gauge-end, connnect the shield to your new ground wire you installed. This should get any interference being induced into the wires down to virtually nothing.

If you do this and it's not fixed, I'd say the parts are bad, not the wiring. Doing all 3 of these guarantees the wiring is not the problem.

<p>That's my current plan. I'm going to get them all on the same ground plane. Then give them their own power source. If that doesn't solve the issue I'm going to ask for a refund.</p>

<p>Props for the shielded cable idea. I'd rather not have to go to that length but whatever is needed.</p>

Good luck! I bought some 18-4 shielded cable off of ebay for around 15 bucks shipped a while back. It's pretty tough, made for CNC equipment.

Like this: 18 4 AWG 25&apos; ft Stranded Shielded Wire Cable for CNC Stepper Servo Motors Alarm | eBay

I don't think it's necessary if the sensor are simply variable resistors that the gauge reads, but it's worth a shot if nothing else has worked.

<p>I think I have some of that laying around somewhere. I don't think it will make a difference though. I would have to go find my signals and systems book to double check that though. Where is @Joe Perez when you need him.</p>

It probably won't. The behavior your gauges show a linear/climbing shift in behavior when under load, which exactly looks like a ground offset changing under load, which is a wiring problem not a shielding problem. But I threw it in there since if you did all 3 of those and it still malfunctions, you can then guarantee it's no the wiring. As long as the sensors are variable resistors then the gauges are simply measuring the change in current, and induced noise into to the wire would result in jitter, not a linear climb/fall as you've shown.

<p>I can live with jitter. That won't bother me. Being off by 50+ degrees does bother me.</p>

<p>Hoping you fix it, as I planned on buying the oil/water temp gauge for my cluster.</p>

Controller, sensor, whatever.

Don't you need the power source to be (ignition) switched, though? Or are gauges that insignificant a current draw?

<p>I think he means for testing. I would put a switched relay in if it was required.</p>

Ordered new senders last night. I'm not going to run a shielded signal line for a one wire resistive sensor input :rofl:

The only thing I can think to do to add grounds to the temp senders is to drill them through the hex (like you do with safety wire) and ground them to the block, or at least the same location as the gauge.

https://www.miataturbo.net/attachmen...ine=1438195052
https://www.pegasusautoracing.com/pr...asp?RecID=5738

These things are supposed to top out at 320°F, Aidan, did you manage to find the notes you took for the senders? If not, I'll probably boil these bitches when they show up and try to come up with some numbers.