Injector Pulse Width

In the scanner, does the reported IPW number ignore:

• fuel injector characterization modifiers (vacuum, voltage, temp offset)
• fuel trims

My understanding is that the scanner IPW values reflect airflow into the engine, injector flow rate (at the current fuel pressure) and commanded AFR. So if you are running lean or rich at any given time IPW would not deviate.

Here is an example of what I am talking about: https://forum.hptuners.com/showthrea...l=1#post682824
Side note: what ever happened to HJTRBO?

He logged in 3 days ago.

I guess I always thought it literally was the Pulsewidth. Which we know is all dependent on a slew of variables, but primarily Dynamic AF including trims along with EOIT and RPM.

i believe its the end commanded PW after all variables, i have had an issue years ago with it flooding on startup because of some transient fuel table changes (bug fault i think), it commands over 200ms PW as soon as it fires that is shown so if it wasnt the applied end PM it should show normal PW and being a transient change it should be very minimal at startup

Quote:

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Originally Posted by Cringer

In the scanner, does the reported IPW number ignore:

• fuel injector characterization modifiers (vacuum, voltage, temp offset)
• fuel trims

My understanding is that the scanner IPW values reflect airflow into the engine, injector flow rate (at the current fuel pressure) and commanded AFR. So if you are running lean or rich at any given time IPW would not deviate.

Here is an example of what I am talking about: https://forum.hptuners.com/showthrea...l=1#post682824
Side note: what ever happened to HJTRBO?

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Injector Puslewidth PIDs (12C3 and 12C4) reflects final IPW without injector offset.
It includes commanded AFR, IFR with all corrections, Transient fueling (wall wetting), POSD Eq Ratio multiplier, Fuel Trims and Short Pulse Adder.

Quote:

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Originally Posted by verlon

Injector Puslewidth PIDs (12C3 and 12C4) reflects final IPW without injector offset.
It includes commanded AFR, IFR with all corrections, Transient fueling (wall wetting), POSD Eq Ratio multiplier, Fuel Trims and Short Pulse Adder.

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Thank you again Verlon!

Questions:

• What offset are you referring (tip temp)?
• What is the POSD Eq Ratio multiplier?
• As far as the transient though, that is where I have major questions...since you brought it up. If what you are saying is true, then [IPW] = [Main Pulse] + [Make Up Pulse]. Correct?

Quote:

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Originally Posted by Cringer

What offset are you referring (tip temp)?
What is the POSD Eq Ratio multiplier?

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Offset is [ECM] 12303 + ( [ECM] 12308 or [ECM] 12309 )
POSD - Postcat Oxygen Sensor Diagnostic. Intrusive test for downstream O2 sensors.

Quote:

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Originally Posted by Cringer

As far as the transient though, that is where I have major questions...since you brought it up. If what you are saying is true, then [IPW] = [Main Pulse] + [Make Up Pulse]. Correct?

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Yes and no.
IPW PIDs is an average for the bank.
Since Makeup Pulse is required IPW is changed enough during Main Pulse so what exactly IPW do you mean? At what moment? :)
At the moment of SOI this will be true : [Main Pulse] = [IPW] + [Offset]

Quote:

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Originally Posted by verlon

Offset is [ECM] 12303 + ( [ECM] 12308 or [ECM] 12309 )
POSD - Postcat Oxygen Sensor Diagnostic. Intrusive test for downstream O2 sensors.



Yes and no.
IPW PIDs is an average for the bank.
Since Makeup Pulse is required IPW is changed enough during Main Pulse so what exactly IPW do you mean? At what moment? :)
At the moment of SOI this will be true : [Main Pulse] = [IPW] + [Offset]

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Thank you for the clarification.

One last question, over what time frame is the average determined? Is it two revolutions of the crank, that way each cylinder goes through one complete cycle?

Quote:

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Originally Posted by Cringer

One last question, over what time frame is the average determined? Is it two revolutions of the crank, that way each cylinder goes through one complete cycle?

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Its just average of last calculated IPWs for all cylinders of the given bank.

I had wondered the same but always assumed it was total pw.