GRT Probe Failures

Oil temp probe bad in the first hour. Replaced and works fine now.
The Fuel pressure unit was reading 0 and -1 psi inflight recently. But last flight it was 3 and higher. (Carb) so not sure what is going on here.
The Carb temp probe starts at close to ambient temp before start up and from there climbs to 127 degrees and stays no matter what you do.
The fuel flow is working but over a 25 gallon burn period it was off 3.5 gallons of what was actually used. I dont consider this a failure just need to adjust it?? if possible.

These were all new and plane has less than 15 hours.

Check your engine ground strap. I bet it's bad.

Edit: Yeah, you may need to adjust the fuel flow. There's a fairly simple procedure for adjusting the k-values. GRT and Dynon use the same flow meter. Calibration procedure should be in the GRT manuals.

Ground Strap

Ground strap is good to go. If that was bad Wouldn't I be having all sorts of issues?

First I will take it that you have set all the AUX value in the GRT EIS. The default are not correct and each need to be set for the given probe. I suspect this since you are reading values but not the correct on.

Also as Jamie said, the ground may be the cause of it if the values are set correctly. A bad ground will work but erratically.

Most are expected Conditions

See notes embedded below

vonjet said:

Oil temp probe bad in the first hour. Replaced and works fine now.

Sounds like infant mortality, or it had a bad ground
The Fuel pressure unit was reading 0 and -1 psi inflight recently. But last flight it was 3 and higher. (Carb) so not sure what is going on here.

Very typical - lots of folks see this, and there are theories why. My guess has always been that at high fuel flows, the pressure is fairly low because it is all flow. The other reason I think it might read low is that senors are usually up near the top of the firewall, and therefore, lose considerable "head" from what the carb is seeing. Carbed fuel pressure is pretty low to begin with.
The Carb temp probe starts at close to ambient temp before start up and from there climbs to 127 degrees and stays no matter what you do.

I read a recent discussion on this - you are really seeing carb body tem, becasue the probe is in the metal carb body. Not unusual to see it this high. I have never installed on, becasue I don't know how it relates to carb air temp or the potentil for icing. From what I rememebr seeing it a little above 100 degrees is normal.

The fuel flow is working but over a 25 gallon burn period it was off 3.5 gallons of what was actually used. I dont consider this a failure just need to adjust it?? if possible.

Definitely needs airplane-specific calibration. I have usually found that in most RV installations, it reads high when the boost pump is on. This measn it will show more fuel used than actual, which is an "error" on the safe side. It can take a number of fuelings to dial in the right parameters for your installation. A good Phase 1 task.
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