Changed location of MAF sensor and now i have P0171, P0174 and P0315

[broke Chevy]

I'm slowly learning HP tuners so don't laugh if the questions are stupid.

First my truck specs:
1998 Chevy S10 with 2004 LQ9 and 4L80e
BTR Stage 2 truck cam (BTR31218110)
Stock intake manifold and injectors
Majestic motorsports out of Jacksonville NC performed attached tune.

What I did:
There is very little space for an air cleaner under the hood of my truck. The MAF sensor and filter assembly was about 10 to 12 inches long in front of the throttle body which was causing a high air inlet temperature. The filter was catching all the hot air coming off the fans.
I changed the location toward the drivers side under the hood and the air temp is much lower now.

I drove the truck for awhile and now have P0171, P0174 and P0315. (the P0315 is weird, I'm not worried about it now)

Can someone point me in the right direction on what to do next. I do not have a wideband yet but I will be ordering one today.

I want to learn how to fix this so if someone knows of a youtube video or document please let me know. I'm thinking I need to adjust the MAF calibration.

Thanks Folks



Screenshot 2023-05-04 163651.png

gas tank change number 2 - Copy.hpt

vcm scanner log 5 4 23.hpl

[Alvin]

Yes you are right.. just re dialing in the MAF. Try looking up how to setup a histogram , now called table and go to town.

This tune needs some help in other areas too. Misfire tables, VE, and timing tables, PE is commanding a pretty rich AFR for the setup too.

[broke Chevy]

Yes you are right.. just re dialing in the MAF. Try looking up how to setup a histogram , now called table and go to town.

This tune needs some help in other areas too. Misfire tables, VE, and timing tables, PE is commanding a pretty rich AFR for the setup too.

Thanks I'll look into that.

[5FDP]

I'd be checking for intake leaks.

[Alvin]

I'd be checking for intake leaks.

changing MAF location or even clocking can change the tune so much that the car might not even run after.

[broke Chevy]

thanks for the info.

[broke Chevy]

Will do, thanks

[broke Chevy]

Update, after running truck for about 50 miles i no longer have any codes. SES light went out. I'm currently installing a wideband have have a question about the PROLINK+ for the wideband. I have the wideband but the PROLINK+ hasn't made it to my house. Do the 5 wires for PROLINK+ wire into the cable of the AEM 30-300 harness. It looks like I will have maintain the MPVI3 plugged into the OBD2 port all the time to observe Air/fuel ratio. Am I correct?

[broke Chevy]

I have the MPVI3 and got the WB connected via a prolink. Now can someone point me in the right direction on how to set up a histogram. I'm getting codes now saying I'm running rich. I relocated the MAF sensor and filter is much larger. 6in vs 4in air filter which is now located in a better place under the hood.

[horsepowerguru]

Just the same as the histogram you had setup to tune your MAF or VE but instead of LTFT or STFT (or whatever you were using, you replace that with the info from whatever prolink+ channel (red, blue or whatever) and then you add it to the channels list using the transform i believe. im not around my laptop at the moment but i can look later and tell you exactly if you havent figured it out by then.

[broke Chevy]

Please provide the additional info if you can. thanks

[horsepowerguru427]

for the histogram its going to be under External Inputs> MPVI, MPVI2+> Prolink, Prolink+> RED, BLue (whichever color youre using.)

To add it to the channels is the exact same, however after it is added you need to let the computer know what the data it is getting means. So, add channel, right click on that channel (it should say mpvi2+ red or something similar) > transform> air fuel ratio> then select the model and type of WB you have. If it does not have it on the list youll have to manually input the math data and apply it. A new WB should come with the user math required to make it work instead of the transform feature, but if you have a name brand WB then it should be on the transform list.

I threw in some screenshots for the histo setup hoping it helps you out. Personally, I find i get better results tuning low and mid throttle with just fuel trims and then WOT and PE with a WB. My truck ran fine after it was fully tuned with the WB but i got better response and mileage when using STFT. However, that is just personal opinion/preference. there are lots of people who do it differently with great results as well.

Also, im currently looking at your tune, Remember to smooth your MAF curve in small sections or increments after you get it dialed in. interpolate between cells that you are missing YOUR data in and make sure youre curve is nice and smooth when finished. Right now its crazy looking lol Same with VE. When i do a VE log and input the data (paste special> multiply by % half) there are always cells in the data that you dont hit, so interpolate small areas to get that data more accurate instead of just smoothing the whole dang map at once. I included a screenshot of an example of what im saying and each area circled should be done seperately so the data in those areas fall in line with the data you collect. Just make sure the first and last cell of the interpolate data is YOUR data collected and not something that existed in the MAP previously.

[broke Chevy]

for the histogram its going to be under External Inputs> MPVI, MPVI2+> Prolink, Prolink+> RED, BLue (whichever color youre using.)

To add it to the channels is the exact same, however after it is added you need to let the computer know what the data it is getting means. So, add channel, right click on that channel (it should say mpvi2+ red or something similar) > transform> air fuel ratio> then select the model and type of WB you have. If it does not have it on the list youll have to manually input the math data and apply it. A new WB should come with the user math required to make it work instead of the transform feature, but if you have a name brand WB then it should be on the transform list.

I threw in some screenshots for the histo setup hoping it helps you out. Personally, I find i get better results tuning low and mid throttle with just fuel trims and then WOT and PE with a WB. My truck ran fine after it was fully tuned with the WB but i got better response and mileage when using STFT. However, that is just personal opinion/preference. there are lots of people who do it differently with great results as well.

Also, im currently looking at your tune, Remember to smooth your MAF curve in small sections or increments after you get it dialed in. interpolate between cells that you are missing YOUR data in and make sure youre curve is nice and smooth when finished. Right now its crazy looking lol Same with VE. When i do a VE log and input the data (paste special> multiply by % half) there are always cells in the data that you dont hit, so interpolate small areas to get that data more accurate instead of just smoothing the whole dang map at once. I included a screenshot of an example of what im saying and each area circled should be done seperately so the data in those areas fall in line with the data you collect. Just make sure the first and last cell of the interpolate data is YOUR data collected and not something that existed in the MAP previously.

Thanks, there is a lot of good information here. I will let you know how it works out.

[broke Chevy]

for the histogram its going to be under External Inputs> MPVI, MPVI2+> Prolink, Prolink+> RED, BLue (whichever color youre using.)

To add it to the channels is the exact same, however after it is added you need to let the computer know what the data it is getting means. So, add channel, right click on that channel (it should say mpvi2+ red or something similar) > transform> air fuel ratio> then select the model and type of WB you have. If it does not have it on the list youll have to manually input the math data and apply it. A new WB should come with the user math required to make it work instead of the transform feature, but if you have a name brand WB then it should be on the transform list.

I threw in some screenshots for the histo setup hoping it helps you out. Personally, I find i get better results tuning low and mid throttle with just fuel trims and then WOT and PE with a WB. My truck ran fine after it was fully tuned with the WB but i got better response and mileage when using STFT. However, that is just personal opinion/preference. there are lots of people who do it differently with great results as well.

Also, im currently looking at your tune, Remember to smooth your MAF curve in small sections or increments after you get it dialed in. interpolate between cells that you are missing YOUR data in and make sure youre curve is nice and smooth when finished. Right now its crazy looking lol Same with VE. When i do a VE log and input the data (paste special> multiply by % half) there are always cells in the data that you dont hit, so interpolate small areas to get that data more accurate instead of just smoothing the whole dang map at once. I included a screenshot of an example of what im saying and each area circled should be done seperately so the data in those areas fall in line with the data you collect. Just make sure the first and last cell of the interpolate data is YOUR data collected and not something that existed in the MAP previously.

In reference to wb histo setup.jpg (2nd jpg). take a look at the filtering in your graph display layout and take a look at mine. Do i need to add the filtering to mine?

[horsepowerguru427]

no, if you used the transform feature you dont have to use the WB math (or shouldnt) you can however filter data out that you dont want using other math. for instance, i like to use [2189.156] > 10% so it doesnt collect the data when TPS is under 10%, which is around the area you get into idle tables

[broke Chevy]

no, if you used the transform feature you dont have to use the WB math (or shouldnt) you can however filter data out that you dont want using other math. for instance, i like to use [2189.156] > 10% so it doesnt collect the data when TPS is under 10%, which is around the area you get into idle tables

Thank You. Oh by the way since I'm still trying to learn how to tune my truck I've been working with PCM of NC because they have mail order tunes. They have been really good at getting my truck to run well. Here are the before and after tunes. (there have been several other tunes between these two, these are the initial and final)


initial tune sent to PCMofNC.hpt

6.16.23.hpt