JPM 700 doesn't match Saratoga steam or digital gauge for TIT

[Jthamilton]

JPI 700 doesn't match Saratoga steam or digital gauge for TIT

Just flew the new to me 98 Saratoga II TC from Iowa to Tulsa since weather wasn't going to let me get to Steamboat.

Enroute I observed about 75 degree difference between the 2 different gauges. I initially used the Piper digital gauge to adjust my mixture when I was around 1600 the JPI was flashing that I had exceeded the TIT max of 1650. After little investigation it seems that the JPI was inaccurate as fuel flows required required seemed to correspond with POH and temp.

What's best way to go about figuring this out? I will have the mechanic take little look maybe they can assess probe attached to the Turbo?

 

[poadeleted20]

JPI's tech support has always been excellent for me.

JPI Technical Support: 1-800-345-4574 l 714-557-3805 l [email protected]

 

[Jthamilton]

Well had annual on the aircraft. Had both probes replaced as I was told they did appear to be in poor shape. I flew home today from Oklahoma and nothing had changed. Still has significant discrepancy between the 2. I understand probe placement may be responsible for this. However when I can't get close to POH numbers for normal cruise and economy cruise isn't going to happen based on fuel flows to keep the JPI less than 1650 TIT.

I have sent email tonight to JPI, but the whole fuel flow thing is bugging me.

Sorry not sure how to make pic right side up.

 

[mondtster]

I'd start by applying a heat source with a known temperature to both probes and see what the gauges indicate. I'm guessing the shop just replaced parts rather than testing first?

 

[Jthamilton]

Yeah I'm going to have my regular mechanic up here take a look after talking with JPI.

Guys that did annual got great reviews from others I know I think they did good job overall but all they said was the probes were quite worn.

The biggest thing bothering me is I can't rely on performance charts due to the difference.

 

[Clark1961]

Calibration of both systems might be in order. I had to have the Piper system calibrated after replacing the probe and indicator. The EI system has been stable and accurate.