I threw my JM Fab 3" intake tube back on my car yesterday since now I know a hell of a lot more about tuning since the first time I tried installing it. The issue last time was during cruise speeds low load high rpm (basic highway driving) my uego would swing rich and then back to stoich. Then rich and then 14.7 over and over again. This time after installing it of course its doing that same thing again. I raised the maf comp a little in those areas and it actually made the problem worse (which is weird because obviously I was expecting the opposite affect) so then I went the other direction and lowered those cells lower then stock settings and it helped a little bit but its certainly not perfect, or anywhere near perfect for that matter. Can I just set the maf comp back to stock and use the injector latency values to fix this issue instead guys? Any advice at this point would be super appreciated. Thanks.

 

Also I'm on tephra v7. I noticed that the maf comp table values on tephra vs stock Rom 88590015 is way different. Like way way different. I was using the stock accordion intake before though on v7 and the afr was perfect at all times.

 

Up

 

The MAF comp or MAF scaling tables are what's needed to clean up the AFR the best. The procedure takes an hour or two of driving and tweaking. You'll need to log MAF Hz and STFT at steady rpm and throttle at several different MAF Hz values, e.g., at 100 Hz, 150 Hz, 200 Hz, etc. Adjust MAF compensation or MAF scaling until STFT hovers around zero for each MAF Hz point you choose. Make sure you have at least 10 seconds of steady rpm and TPS to observe STFT. It's a bit more in depth than tuning injector settings.

 

The scaling in V7 is different but the raw numbers are the same.

 

Exactly what I was looking for, thanks Mychailo. Looks like I have a project for after work tomorrow.

 

I figured out by lowering the maf comp values on the right it made the ecu add in more fuel and by raising those same values it made the ecu pull out fuel. So I take it that's how it works then. Logging of different maf htz at different but steady rpm and tps values is what I need to do at this point. Thanks again for all your help!!

 

Should be the other way around because the scaling values represent airflow.

 

That's what I thought, but I'm finding that when I make adjustments the EXACT opposite is happening. It's really frustrating to say the least. I'm going to throw the stock accordion back on for now until I can figure out what the deal is here. Maybe I have a boost leak that I didn't know about. Thanks again for your advice and help its always appreciated here

 

I have been using maf comp on v7 to make these changes. Would setting comp back to original v7 settings and using the maf scaling (adder already included) table to make these changes yield better or different results. I know in PM you told me either one but would scaling work better then comp? Is that even possible???

 

you'll need to watch the ltft to make sure its not changing. it will affect closed and open loop fuelling.

 

I've got my rear o2 in a spacer currently and remember reading that the rear o2 effects LTFT. Would tephra's simulated rear o2 option suffice for logging LTFT?

 

I could be wrong, but I believe that the rear O2 circuit just needs to be enabled to log LTFTs.

subscribed to this one, i'll have to try what mfred recommended.

I too have issues while cruising, mainly just on the highway, where the AFR swings rich then back to "stoichish". I have an analog wideband gauge and compared to my friends talon (same gauge), even when tracking around stoich, my car seems way less stable. hoping this clears that up.

 

I tried what Mychailo suggested and it helped a lot but not enough to make it "daily driver" worthy. It was still running like crap. It's not what he suggested, what he said is 100% correct but it just wasn't working for me. I put the stock intake back on for now. I'll figure it out later.

 

Interesting. My car had an aftermarket intake when I got it so I always thought there was something else going on like a bad injector. I'll have to give this a try as I don't have a stock intake to go back to (plus I'm too addicted to turbo noise now). Mine isn't bad to drive, its more so something that bothers me seeing the gauge swing around randomly.