IAT sensor resistance
Tranny dipstick poked up through the passenger's side footwell.
06-26-2012, 07:31 AM
#18
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I test my IAT and CTS with a DRB or I'd give you the values.....
06-26-2012, 09:41 AM
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10-19-2013, 02:00 AM
#21
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IAT is used inconjunction with MAP sensor in a speed density based system to calculate airflow and adjust correct injector pulse width. You might screw up A/F and maybe damage the cat, burn a valve, etc putting a fixed resistor in there.
Edit: By fixed resistance I'm referring to the 200 ohm resistor the OP wants to replace his IAT with. Relocating the IAT wont cause the potential issues mentioned.
Edit: By fixed resistance I'm referring to the 200 ohm resistor the OP wants to replace his IAT with. Relocating the IAT wont cause the potential issues mentioned.
Get it guys? Three things influence the temp of the IAT, not just the air.
Me thinks it only works to enritchen, (like a choke) in cold weather.
Could it be the computer ignores it completely as soon as as at comes down to around 200 ohms?
Last edited by DFlintstone; 10-19-2013 at 02:05 AM.
10-19-2013, 11:22 AM
#22
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Better mileage. "is it bad?" Idk, nobody will post their readings.
Thank you BB.
Understood. Well I cleared 21 MPG with about 275K on it and I see no sign of any problem yet. I still don't know what it will do when temps here drop into the 30's I DID PUT IN A 225 OHM RESISTOR.
I'm thinking it is a "minor player" , say compared to engine coolant temp.
Well that's sort of my issue. The charts are for the sensor temp, if it's in plastic it's gonna get one thing, in metal, conduction there, another. Then the radiant heat of the two will be different. (conduction, convection, and radiation are the three ways heat moves).
Get it guys? Three things influence the temp of the IAT, not just the air.
Me thinks it only works to enritchen, (like a choke) in cold weather.
Could it be the computer ignores it completely as soon as as at comes down to around 200 ohms?
Thank you BB.
Understood. Well I cleared 21 MPG with about 275K on it and I see no sign of any problem yet. I still don't know what it will do when temps here drop into the 30's I DID PUT IN A 225 OHM RESISTOR.
I'm thinking it is a "minor player" , say compared to engine coolant temp.
Well that's sort of my issue. The charts are for the sensor temp, if it's in plastic it's gonna get one thing, in metal, conduction there, another. Then the radiant heat of the two will be different. (conduction, convection, and radiation are the three ways heat moves).
Get it guys? Three things influence the temp of the IAT, not just the air.
Me thinks it only works to enritchen, (like a choke) in cold weather.
Could it be the computer ignores it completely as soon as as at comes down to around 200 ohms?
Black89
Last edited by Black89; 10-19-2013 at 11:39 AM.
10-20-2013, 07:01 AM
#24
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Better mileage. "is it bad?" Idk, nobody will post their readings.
Thank you BB.
Understood. Well I cleared 21 MPG with about 275K on it and I see no sign of any problem yet. I still don't know what it will do when temps here drop into the 30's I DID PUT IN A 225 OHM RESISTOR.
I'm thinking it is a "minor player" , say compared to engine coolant temp.
Well that's sort of my issue. The charts are for the sensor temp, if it's in plastic it's gonna get one thing, in metal, conduction there, another. Then the radiant heat of the two will be different. (conduction, convection, and radiation are the three ways heat moves).
Get it guys? Three things influence the temp of the IAT, not just the air.
Me thinks it only works to enritchen, (like a choke) in cold weather.
Could it be the computer ignores it completely as soon as as at comes down to around 200 ohms?
Thank you BB.
Understood. Well I cleared 21 MPG with about 275K on it and I see no sign of any problem yet. I still don't know what it will do when temps here drop into the 30's I DID PUT IN A 225 OHM RESISTOR.
I'm thinking it is a "minor player" , say compared to engine coolant temp.
Well that's sort of my issue. The charts are for the sensor temp, if it's in plastic it's gonna get one thing, in metal, conduction there, another. Then the radiant heat of the two will be different. (conduction, convection, and radiation are the three ways heat moves).
Get it guys? Three things influence the temp of the IAT, not just the air.
Me thinks it only works to enritchen, (like a choke) in cold weather.
Could it be the computer ignores it completely as soon as as at comes down to around 200 ohms?
10-20-2013, 07:02 AM
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10-20-2013, 11:23 PM
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At least that's my take. I think that's what DF was saying as well?
My guess as to what role the IAT takes in fuel calucation is that it is more important than the CTS. Maybe not as much as the O2 and MAP though. The air temp is a direct variable in the air density calculation where as the coolant temp is a bit more indirect. My guess is the CTS is more for cold start enrichment and plays a small part in the normal running fuel calcs.
10-20-2013, 11:45 PM
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I think I understand what he is saying though. Yes, it is mainly an air temp sensor meaning it is supposed to measure the convection heat in the air, but the other two methods WILL affect it in some way as well.HHHHHH............................ more important than the CTS. Maybe not as much as the O2 and MAP though. The air temp is a direct variable in the air density calculation where as the coolant temp is a bit more indirect. My guess is the CTS is more for cold start enrichment and plays a small part in the normal running fuel calcs.
10-21-2013, 12:00 AM
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I just put my best educated guess on the IAT vs. CTS statement. I don't know for sure, but I guess you don't know for sure either? What makes you think CTS is used? What would it calculate from it?
Hate it when that happens. I have to exercise my memory, ugh, so annoying. lol
Last edited by SuperRA; 10-21-2013 at 12:03 AM.