Any methods to test pyrometer?

[JClark]

Hi there, I was wondering if there is any way to test my pyrometer? It seems to be reading lower

than it use to. I am thinking that the new air filter (clean fleetguard) may be letting the engine breath better than the old filter (dirty car quest). Would a new air filter be responsible for a 200 to 300 degree drop in EGT at highway speed? Before, cruising at 70 mph EGT = 600 to 800 and now at the same speed on the same road EGT = 300 to 500. I know outside air temp will have some bearing on this. If the air filter is causing this reduced EGT, then thats great but just to be sure can the pryometer be tested with an ohm meter or some other device?



Thanks so much for your time, John.



Forgot to mention that the pyrometer is mounted pre-turbo.



My air filter system is still stock.



I am running fanless now and have been for about a month and was wondering if this might have something to do with lower egt's.



Thanks again, John.

 

[Alaskaskiff]

There is a temperature resistance relationship that can be accurately checked with an ohm meter. The properties of the thermocouple are fixed.

 

[illflem]

Perhaps the easiest way to check it is to see where the gauge reads in relation to the outside temp when the engine is stone cold. Pyros are only accurate in the middle of their range so don't expect it read right on the mark with the thermometer on your porch. If your block heater has been plugged in the temp will read higher than the outside temp. Easy to see if you are a few hundred degrees off though. Could it be your lower temp coincided with that artic blast we had last week?

48° this afternoon in Hamilton.

 

[Steve Campbell]

illflem

We used to haul a lot of cattle out of Hamilton. 48 deg was probably the highest temp I ever saw when I was there.

 

[JClark]

Thanks guys. It could be just the colder outside air temp. To tell the truth, I really have not been paying too much attention to the pyrometer when I am under normal driving conditions. It may have been reading low throughout the winter months and I just never noticed. I only watched the gauge when I was towing or goofing off but now, with the transmission problem I have, towing and goofing off have gone by the wayside for now.



Thanks for your time, John.

 

[Alaskaskiff]

Come to think of it, my temps have been going up, and I know the filter is getting dirty. I saw movement on the filter minder the other day. Another thing I found was that I was getting low readings due to a bad connection between the gauge and the pyro. I cleaned the connectors and things jumped back into the range that I was expecting.

 

[dieselburner]

Originally posted by JClark

Hi there, I was wondering if there is any way to test my pyrometer? It seems to be reading lower

than it use to. I am thinking that the new air filter (clean fleetguard) may be letting the engine breath better than the old filter (dirty car quest). Would a new air filter be responsible for a 200 to 300 degree drop in EGT at highway speed? Before, cruising at 70 mph EGT = 600 to 800 and now at the same speed on the same road EGT = 300 to 500. I know outside air temp will have some bearing on this. If the air filter is causing this reduced EGT, then thats great but just to be sure can the pryometer be tested with an ohm meter or some other device?



Thanks so much for your time, John.



Forgot to mention that the pyrometer is mounted pre-turbo.



My air filter system is still stock.



I am running fanless now and have been for about a month and was wondering if this might have something to do with lower egt's.



Thanks again, John.

Check to make sure that it is tight in the manifold. I had one back out to where I could see soot aroung the fitting. It was reading a couple hundred degrees low. That's a lot when whe your already living on the edge...

 

[JClark]

Pyrometer problem solved

This is just a note to let you know that I found the problem. Cleaned and tightened all electrical connections and it now works fine. I am kicking myself for not doing this before I posted.



Thanks, John.