I'm working through a problem with my Evo, and I'm trying to get a handle on what could cause a large fluctuation in injector pulse width. Is this fuel pressure related? Would a bad fuel pump cause rapid dips?

Here's a recent datalog:



Notice there are pretty big dips around 4000 and 5000, then a rapid change in IPW from 5800 to 6500. Any thoughts here?

Also, notice that my air fuel (from the narrowband O2) keeps climbing... in other datalogs I've seen, this just levels off. Is this an indication that air is getting into the system after the MAS?

I've checked all the typical stuff (see my other thread here: https://www.evolutionm.net/forums/sh...d.php?t=282691) such as plugs, intercooler piping, wires, and even threw a new O2 sensor in...

Let me know what you think about the IPW... thanks.

 

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No one has any ideas here? I did some reading outside of these forums and found that the IPW is sent from the ECU based on calculations that may include inputs from the TPS, O2 sensor, RPMs, and MAS.

I just swapped out my O2 for a new one... maybe a bad/dirty MAS is throwing this off. Anyone have any experience with this?