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Rig Wrench · 08-30-2016, **(Subject: Multiplexing accuracy )**

How much of a discrepancy is in factory multiplexed gauges and regular old mechanical? I've read on hear that the factory boost gauges can be off, but what about others?
The reason I ask is I've been battling a high egt issue with a cm870 565 for a while now, I'm staring to think I may not actually have one. I can get the gauge to hit 8-900 degrees bob tailing very easy, and in insite it says measured egt of almost 1400 degrees????? I don't see how its possible. Doesn't even burn the never-seize on the pyro probe? It jumps to over 600 on just the slightest throttle imput going down the road. This has been an issue sinse it was new. Has new factory gauge and pyro. Nothing I do seems to make a difference. I'm gonna try a mechanical setup. Just lookin for opinions and insite

08-30-2016, **(Subject: Multiplexing accuracy )**

(08-30-2016 )Rig Wrench Wrote: How much of a discrepancy is in factory multiplexed gauges and regular old mechanical? I've read on hear that the factory boost gauges can be off, but what about others?
The reason I ask is I've been battling a high egt issue with a cm870 565 for a while now, I'm staring to think I may not actually have one. I can get the gauge to hit 8-900 degrees bob tailing very easy, and in insite it says measured egt of almost 1400 degrees????? I don't see how its possible. Doesn't even burn the never-seize on the pyro probe? It jumps to over 600 on just the slightest throttle imput going down the road. This has been an issue sinse it was new. Has new factory gauge and pyro. Nothing I do seems to make a difference. I'm gonna try a mechanical setup. Just lookin for opinions and insite

the insite measured is calculated off of CIT (which is CID and about 5 other things rolled into one), boost, and fueling - it is notorious for being off if any of these sensors are reading funny. i would not worry too much about that.

i would be looking at turbo commanded position, live fuel flow and timing along with intake air temps both COT and imap. these will tell a story to figure out if it is actually high.

Rawze · 08-31-2016, **(Subject: Multiplexing accuracy )**

(08-30-2016 )Rig Wrench Wrote: How much of a discrepancy is in factory multiplexed gauges and regular old mechanical? I've read on hear that the factory boost gauges can be off, but what about others?
The reason I ask is I've been battling a high egt issue with a cm870 565 for a while now, I'm staring to think I may not actually have one. I can get the gauge to hit 8-900 degrees bob tailing very easy, and in insite it says measured egt of almost 1400 degrees????? I don't see how its possible. Doesn't even burn the never-seize on the pyro probe? It jumps to over 600 on just the slightest throttle imput going down the road. This has been an issue sinse it was new. Has new factory gauge and pyro. Nothing I do seems to make a difference. I'm gonna try a mechanical setup. Just lookin for opinions and insite

The factory EGT for the gauge is calculated, not measured. it is also unstable and unreliable. Put an external pyro gauge on the outside of the manifold like in my videos and be done with it.

What are your manifold temps getting to? -- Ever used a heat gun after pulling off the side of the road after a long hill climb? -That would tell you more about heat issues than watching that stupid factory gauge.

Rig Wrench · 08-31-2016, **(Subject: Multiplexing accuracy )**

It just throws me off cause it has a factory probe in the turbo outlet pipe. But it is not hard wired to the gauge. No I haven't tried shooting it after a hard pull, its not my truck, I'm just doing some work on it. The plan is for a mechanical gauge. This is a cm870. Never ha a dpf.