Map sensor

[BLeeBull]

I have a weird thing going on. a good example starts at about 19 minutes into the log file. As the RPM's climb at wide open throttle the map sensor fluctuates up and down at what seems to be on about a 200 Rpm cycle. (sometimes cycling between 98 and 93 KPA) on the way up through the revs. It as if the manifold pressure trends down for about 200 RPM, then jumps up by a few KPA and then trends down again for the next 200 RPM and the repeats the cycle. It makes the MAP reading look like an asymmetrical sine wave. I have included the log and gauge layout file showing the map and wideband. At about the 19 minute mark I do a full throttle run that shows what I am talking about. I seems like the air fuel ratio moves with the map reading. Any insight would be helpful. I was reading 100 KPA with key on engine off right before this log.

6.0 lq9
smallish 220/224 cam
long tubes
TBSS intake

[blindsquirrel]

Things that can't be answered based on only the info you've provided:

Is the MAF completely removed? Full-time speed density? (tip: DO NOT log MAF channels if the MAF is not being used)

What is the air intake/airbox/filter setup? Is it creating a restriction? I don't see anything dramatic n the log that would point to that, but if you have a concern of this general type that should be checked carefully. It's normal for MAP to fall off some at high RPM because everything in the airstream creates some amount of restriction. Even a largish diameter straight piece of plain tubing. Even a bare nekkid throttle body with no ducting attached at all will still show some MAP drop-off as RPM increases.

I do not see anything especially abnormal in the log file you posted. If you have a specific question about one specific behavior, it helps to trim the log down to only show the thing. 23 minutes of driving around and 10 seconds of the thing you have a question about is really frustrating to hunt through.

What are the narrowband voltages doing during the issue? They aren't being logged.

What does the Cylinder Airmass do during the issue? It isn't being logged.

What do the injector PWs do during the issue? They aren't being logged.

What's in the tune file? Don't know, it wasn't included.

[BLeeBull]

Is the MAF completely removed? Full-time speed density? (tip: DO NOT log MAF channels if the MAF is not being used


What is the air intake/airbox/filter setup? Is it creating a restriction? I don't see anything dramatic n the log that would point to that, but if you have a concern of this general type that should be checked carefully. It's normal for MAP to fall off some at high RPM because everything in the airstream creates some amount of restriction. Even a largish diameter straight piece of plain tubing. Even a bare nekkid throttle body with no ducting attached at all will still show some MAP drop-off as RPM increases.

I do not see anything especially abnormal in the log file you posted. If you have a specific question about one specific behavior, it helps to trim the log down to only show the thing. 23 minutes of driving around and 10 seconds of the thing you have a question about is really frustrating to hunt through.

What are the narrowband voltages doing during the issue? They aren't being logged.

What does the Cylinder Airmass do during the issue? It isn't being logged.

What do the injector PWs do during the issue? They aren't being logged.

What's in the tune file? Don't know, it wasn't included.[/QUOTE]
SD


Yes full time SD no MAF in place. Neglected to stop logging it.

the intake, and airbox are the stock Escalade with oiled gauze filter

I never looked at narrow band just the wideband. It never occurred to me to look at it

I didn't realize a log could be chopped up and a small section of it be posted. Not sure how. That is why i gave a time stamp

not sure what to log. all I was curious about is why does the map reading move up and down while at wide open throttle. I expect and understand that it will drop some because of restriction. What I didn't expect is for it to oscillate up and down as the RPM climb.

[blindsquirrel]

I didn't see anything I'd call an oscillation in that log, nothing that didn't correspond to throttle movement, at least not in what I think was the WOT section you mentioned. There will be some 'noise' in sensor readings sometimes, like bouncing between one min increment and the next.

You can trim down logs. Log File > Export Log File, then select format: .hpl and range: Visible Range (use the zoom function to set what's shown and what's not)

You can also go drive around and then tap the spacebar to stop, then tap again to restart, do your WOT thing where you think it acts weird, then tap spacebar again to stop. You end up with a separate small file that only shows the relevant part.

[BLeeBull]

I didn't see anything I'd call an oscillation in that log, nothing that didn't correspond to throttle movement, at least not in what I think was the WOT section you mentioned. There will be some 'noise' in sensor readings sometimes, like bouncing between one min increment and the next.

You can trim down logs. Log File > Export Log File, then select format: .hpl and range: Visible Range (use the zoom function to set what's shown and what's not)

You can also go drive around and then tap the spacebar to stop, then tap again to restart, do your WOT thing where you think it acts weird, then tap spacebar again to stop. You end up with a separate small file that only shows the relevant part.

That was exactly the info I needed, thank you. Here is the much smaller file. It is a short full throttle going up a slight hill.

[blindsquirrel]

I still don't see a problem. I was going to ask yet again that cylinder airmass/O2s/injector PW/etc. be added but decided that I am tired and would rather just take a nap or something.

[BLeeBull]

I still don't see a problem. I was going to ask yet again that cylinder airmass/O2s/injector PW/etc. be added but decided that I am tired and would rather just take a nap or something.

If it is normal then it's normal I guess. Stupid Question: what will the narrow band sensors tell me that the wide band can't? Just trying to learn.
i understand you needing cylinder airmass and injector pw, but I am confused about the NB sensors.
I will have to go do a drive to include the other parameters.
are you saying that what I am seeing is most likely noise?

[BLeeBull]

I think my air intake tube is the issue. I put a cone filter directly on the throttle body with the IAT stuffed inside the filter. It no longer feels like it "surges" at wide open throttle. Thanks for trying to help, sorry i don't know what to log to get help. Here is with the new filter setup.