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+--- Thread: CM 871 won’t regen (/showthread.php?tid=4485)
RE: CM 871 won’t regen - Lonestar10 - 05-05-2019
IMAP reads 0 with key on because its 0 "Gauge" pressure and the Baro helps it stay 0'ed as the baro reads "Absolute" pressure.
use this example for Absolute and Gauge Pressure in PSI and you have the gauge in your hands.
Absolute Pressure - 14.7 PSI
Gauge Pressure - 0 PSI
Gauge is Absolute minus atmospheric pressure.
When i was in Ethanol you could tell these sensors apart on the DCS "The control systems" if a reading showed PSIA it was Absolute and PSIG was Gauge.
RE: CM 871 won’t regen - theironoracle - 05-05-2019
Lonestar10,
Thanks for that info it clears that up. So the barometric pressure is actually there obviously causing voltage X on both sensors but the computer is calculating X-X so we see zero on imap? Now I want to go back in there and compare the voltage at key on engine off. I realize they may be different if they used different size strain gauges but I have to feed my curiosity.
TIO
RE: CM 871 won’t regen - theironoracle - 05-05-2019
Without knowing any better the idea of “rare and precious metals” is gold and titanium like the wedding bands I wear. Neither of which is going be damaged by any pressure or heat a steam cleaner. Now let me say I do believe you and I will NOT be Washing these outvwith water anymore. You resume speaks for itself and that is why I joined this forum and will absorb everything on it and begin to contribute as I understand.
I don’t know why it hasn’t been obvious that 50% of the holes had bottoms in them? I will definitely take a much closer look.
TIO
RE: CM 871 won’t regen - theironoracle - 05-05-2019
I forgot to ask. Is there a way to set this account so I get email notifications when someone responds to a thread I have posted?
TIO
RE: CM 871 won’t regen - Magard - 05-05-2019
Just a little help with pictures. If your phone is taking pictures “live” when you post them it will rotate them. It’s frustrating. Edit your pictures to normal photos then post they will then be straight.
RE: CM 871 won’t regen - Rawze - 05-05-2019
(05-05-2019 )theironoracle Wrote: I forgot to ask. Is there a way to set this account so I get email notifications when someone responds to a thread I have posted?
TIO
nope. email system is disabled on this old-school forum for security protection and member anonymity. that is also why there is no password recovery system. for the same reasons.
RE: CM 871 won’t regen - Lonestar10 - 05-05-2019
I dont know if the voltages will tell you anything. it could be that IMAP sees say 28.7 KPA and Baro sees 28.7 KPA and then computer just subtracts 28.7 from the IMAP and shows a 0 Readout.
Rawze is the electrical enginerd here with his kick ass toys like his new Arduino for testing turbos he would know better.
Only type of sensors/valves im used to using have constant voltages and use a 0 to 20 milliamp scale to send out their data. so in the computer system there would be a scale like this.
Say the scale is 0 to 200 PSI
0 Milliamp = 0 PSI reading
10 milliamp = 100 PSI reading
20 milliamp = 200 PSI reading
RE: CM 871 won’t regen - Unilevers - 05-05-2019
the precious metals are in a coating sprayed onto the ceramic substrate. By washing them you wash the coating and them off slowly more and more each time. Usually by the 4-6 time the DPF and doc are just bare ceramic and are useless.
The DPF is not a pass through filter, it has blocked passages so soot has to travel through multiple passages. pressure washing destroys them.
RE: CM 871 won’t regen - Rawze - 05-05-2019
(05-05-2019 )Lonestar10 Wrote: I dont know if the voltages will tell you anything. it could be that IMAP sees say 28.7 KPA and Baro sees 28.7 KPA and then computer just subtracts 28.7 from the IMAP and shows a 0 Readout.
Rawze is the electrical enginerd here with his kick ass toys like his new Arduino for testing turbos he would know better.
Only type of sensors/valves im used to using have constant voltages and use a 0 to 20 milliamp scale to send out their data. so in the computer system there would be a scale like this.
Say the scale is 0 to 200 PSI
0 Milliamp = 0 PSI reading
10 milliamp = 100 PSI reading
20 milliamp = 200 PSI reading
if someone is that curious...
The IMAP has a "guage" type of pressure sensor.
https://www.smartec-sensors.com/cms/media/Datasheets/Pressure-DIL/SPD_Pressure_Sensor_Families.pdf
What sticks down into the manifold inside the little cage part is the temp sensor portion of it.
