The EGR temperature sensor is out of the car. Multimeter reads infinite ohms when at room temp. Putting it into very hot water - ohm reading appears. Starts at 175k and gets down to 80k, which seems to be way out of range. I think it should start at 400 ohms when cold then ohms drop as it heats up. ???

Are you getting a code 55 with the sensor connected?

Edited November 21, 2025Nov 21 by SuspiciousPizza

No codes. We know that EGR will affect NO (ppm). Now, I did pass California smog last week, but I am curious why the NO (ppm) @15mph was reading a whole lot higher than NO (ppm) @25mph.

This last test showed 800 ppm @ 15 mph and 67 ppm @ 25 mph. Am unsure whether or not EGR needs looking into.

What revs was the engine doing at each of these readings, and same gear/load? That could tell you a lot about what’s going on in your engine. 

My recent 11/10/2025 test report page says 15mph@1824 rpm. And 25mph@2100 rpm. RPMs seem close to what they should be. The ignition timing read 18 BTDC.  The engine burns no oil. It has maybe 6k miles on the rebuilt engine. The EGR valve holds its vacuum. So, I'll re-check all of the vacuum hoses. But that egr temp sensor has me wondering. And hey, thanks for your input.

Edited November 23, 2025Nov 23 by rickyhils
remove unneeded words