Trouble with MAP sensor reading

[Tristen]

Greetings. I recently got an unlocked PCM from Holley and a Trinity2ex. I'm having some trouble with idle and rpm hanging after taking my foot off the gas. did a smoke and starter-fluid leak test, and didn't find anything.

I've replaced the MAP sensor (carquest OEM replacement), and it's giving me SOME data, but not very much. I was wondering if it's reading correctly, or needs to be re-scaled, or if it's shorted open.
I've attached a few logs, and the current tune information.

using 93 octane 0% ethanol, with the diablo tune.
Mods - ported tb (BBK-1843), mopar intake, AFE twisted headers, AFE mach-3xp exhaust w/h-pipe, 2016 RT Plus Shaker Manual 6

Thanks in advance
Tristen

[mikel]

\your issues are more likely tied to that TB than anything in the tune. We don't adjust anything idle related in the tunes. why did you replace the MAP sensor?
Im guessing the issue is same with the stock tune restored, which should clearly p[point to one of the mods you made, and the TB is the most likely culprit.

[Tristen]

I replaced the map sensor because the behavior of the Barometric Pressure reading didn't change before replacing the PCM, or the tune, or before or after the ThrottleBody.
Since the car isn't getting "uncounted" air from an intake leak, and Baro reads a steady 14 psi, that means the car is assuming the throttle is WOT 100% of the time. ... and it's reflected in the LTFT.

Since i didn't find any intake leaks, and i replaced the ecu, the next step was to replace the map sensor. after replacing the map sensor, i found no chances in the readings from it.

that leaves me with a couple remaining places to troubleshoot.
1 - the map sensor is not a PID diablosport reads, and everything is functioning normally, and i should seek a tuner to refine the current tune
2 - the pigtail or the wiring loom has a short in it, and the PCM is getting a steady 14 psi at all times because of that. and i can't refine the tune till the map sensor is reading properly
3 - the way that diablosport reads the map sensor is not functioning properly. and i can't refine the tune till the map sensor is reading properly

[mikel]

I think you are way off here, let me try to help.

14.7 psi is atmospheric pressure, hence it will always be near that value. Nothin about your mods should run poorly on the stock tune. if you reload the stock tune, and the issues persist (not map, but actual idle or drivability issues) then id start by putting the stock TB back on. When that resolves the issues, you have to decide if adding a throttle body, which will do little to increase performance, is worth the hundreds of $ it might take to properly dial it in with custom tuning vs just running the stock one

[Tristen]

does that mean that baro should always read either 13.92 or 14.07 and no other values?
shouldn't there be other pressure values?
what does baro read then? the pressure outside the car?

because, as i mentioned, i've already put the stock throttle body back on, and haven't experienced any changes in the data provided by that point. Is there another PID i should look at to read the pressure inside the manifold?

I can't even begin to tune the stock ThrottleBody if i'm getting bad data.

[mikel]

let me ask this. if you weren't looking at the MAP PID data, what would you describe to be the issue? You mentioned throttle hang, I see that with aftermarket throttle bodies regularly, is that still present with the stock TB?
MAP will drop a bit at idle or cruise when you are in vacuum (pulling pressure from the manifold) and at WOT should be close to whatever atmospheric is in your area at that time. I am 99.9% certain you have no MAP related issues and that the data you are seeing for MAP pressure is correct.

[Tristen]

throttle hang is present in both cases, and the LTFT is something like -12% to -15% and only reaches near 0 in wot conditions.
it's hard to determine why, since i can't read any pressure changes at all when doing data-logs, and there's no check engine light present, but the car is running significantly rich, all the same. (based on ltft, i'd guess it's reading more air than is actually present at idle, because the map sensor is sending 14psi to the PCM instead of the actual manifold pressure ) .

meaning- the car is being told that more exists than actually does.... the opposite effect replacing the throttle body usually presents, where idle stays high due to increased airflow over stock (and runs lean)

or i don't know what the actual PID is that i should be looking at to get those readings. if barometric pressure is the wrong data-point, i'll need another data-point i can use to calculate airflow other than barometric pressure.

the baro data is essentially a square wave that only reads 13.92 or 14.07, and no other values whatsoever.... it's not even useful as a barometric sensor in this state.

so i'm trying to figure out
do i have the right pid to calculate airflow?
is it getting good data?
the 2-value square wave would indicate either the sensor isn't sending the right data, or the receiver isn't reading it properly. if it only provided one value, i'd lean more towards the sensor, but it's hard to tell since i didn't write the software for the monitor.

I'm 99.9% certain, that if you look at the data from my original post, you would have come to the same conclusion. ... my tuner (the person) only took 10 seconds to tell me something was wrong with the data.

Anyway, my next step in troubleshooting is probably going to be a multi-meter, but i'm not too enthusiastic about rewiring that loom section, lol... (I need help... not someone who's gonna ignore what i say, and the data, and treat me like an idiot ) ... And probably a HP tuner.

[mikel]

Apologies if you feel I am treating you that way. Just trying to help. I wish you the best of luck figuring it out.

[Tristen]

do you know why the barometric sensor doesn't change with the air pressure?

i was hoping to figure out if i was even reading the right PID, but at this rate i haven't gotten any help at all. ... or any of my questions answered.

[mikel]

Baro rarely changes much at all. You should see small variances in the pressure, but at sea level, it should always be very close to 14.7 psi.

Please restate any questions you would like an answer to and I'll see what we can do to help.


Thanks