Problem adding MAT to $0D TBI 7427, Not pulling timing.

[96lt4c4]

Most of you guys have seen that I am successfully running boost on a 7427 with a 2 BAR map. The truck is running great. I added a MAT sensor to the setup so that when the air coming in gets hot, I can rely on the sensor to pull some timing. For some reason that function is not working. The MAT itself is working, because I can log the temp. This "MAT & CTS Blend Multiplier vs. Airflow" is working as well. I have the MAT sensor flag set.

I have the MAT Bias set to 9.8

As a test I populated the entire "MAT Spark Advance Compensation vs. MAP vs. Temperature" table with -10 degrees, and drove the truck. My timing showed the same as what is in my Main Spark tables. the ECM never pulled any timing base on MAT. I am trying to figure out whats going on. I did find a flag that the CPI bins have set that the TBI does not, that has to do with the MAT, I tried both ways, didn't make a difference. Its at 442F "LD SELECT, ( 0 = VACUUM 1 = RPM) MAT". Could it be something with the Negative or Positive multipliers?

[96lt4c4]

I just noticed the CPI bins do not have anything in the Main spark bias? They are zeroed out.

[CFI Z51]

Cool build...wish i could help..
I did notice you had a malf code 25 Mat HI set in the log, I don't know if this would cause the mat compensation not to run..or when it was set.
as for the biases and how they all play together

[96lt4c4]

Cool build...wish i could help..
I did notice you had a malf code 25 Mat HI set in the log, I don't know if this would cause the mat compensation not to run..or when it was set.
as for the biases and how they all play together

Huh....I didn't even notice that. I don't have a SES light. I will take a look at it. I zerod out the MAin Spark Bias, which I knew would screw up my timing tables. So I copied them first, zeroed the bias, saved, then copied the table back in. Set it up like the CPI bin. I don't think it did anything.

I don't know where everyone is on this forum lately, I am hearing a lot of crickets chirping. Sometimes I wonder if I am one of the only ones left messing with these old PCM's. Probably should have upgraded the 411 LS1 computer and use my HP Tuners.

[PJG1173]

I don't know where everyone is on this forum lately, I am hearing a lot of crickets chirping. Sometimes I wonder if I am one of the only ones left messing with these old PCM's. Probably should have upgraded the 411 LS1 computer and use my HP Tuners.

I don't think its lack of people on the site, its a shortage of people who know enough to help on the more advanced topics. I have been watching some of these threads as I am interested in using the MAT also when I go to MPFI.

[brian617]

Every time the MAT subject comes up on here it goes about 4-5 post then dies. I'd really like to get in working in my truck but the first time I tried it my BLMs went nuts. Wish I had time to figure it out...

[96lt4c4]

I don't think its lack of people on the site, its a shortage of people who know enough to help on the more advanced topics. I have been watching some of these threads as I am interested in using the MAT also when I go to MPFI.

Yeah, I thought about that too....I guess I am in uncharted territory here...LOL. Might take me a while to figure it out. Not sure why I am throwing a code and the light is not coming on though. The sensor seems to be working and reading air temp. Maybe that code 25 is part of my problem.

[JeepsAndGuns]

I added a MAT to mine (7427, mpfi) but I could never really get it to do anything worthwhile. I copied in the CPI parameters and fiddled around with them some, but most of the time, it never really did anything. It seems like for some reason I was having some type of issue that went away when I disabled it. So I just left it disabled and said heck with it. Its still installed in my intake and hooked up, can even still see the temp in the data stream, I just have it disabled in the bin.

Like said above, your probably in uncharted territory, as I do not think many people have fooled around with adding a MAT to the 7427 non cpi bins.