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MAF TUNED EASY, SD EXTREMLY LEAN?

Practical Reflash Tuning

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Discussion and questions related to the course Practical Reflash Tuning

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Thanks for the awesome courses Andre, they have truly given me the confidence to start tuning.

I am using HP tuners on a GM 0411 LS1 PCM 7.4L Vortec conversion. Base tune is from a very reliable source for this conversion. Using your methods, I was easily able to tune the MAF and it runs great. When I switched to SD for tuning the VE table, the engine is super lean reading 1.6-1.8 on my wide band at idle or part throttle, and of course barely runs. I am afraid to actually drive it in SD. I have nearly doubled the figures at idle on the table with no effect. I can only find 1 VE table in my version 3.6 software. Not sure if it's related but I have never been able get any trims in blended mode unless I command them from the scanner. When on, they quickly dump fuel, making the motor very rich, it will get to 0.8 within a minute or two. Any Ideas where to start?

Thanks

Bill

If you've gone from a 5.7 litre to a 7.4, my first question would be, have you changed the engine capacity parameter in the software?

Cylinder volume is 0.92508 and 8 cylinders so that looks good. I have attached current tune along with several logs, all low rpm since i can't get over 1400 rpm on SD. Not sure if it's related but I can not get any fuel trims in any mode unless i command closed loop in the scanner. When commanded, the fuel trims get maxed and it will go pretty rich. Is there a mechanical problem that could cause this? i would think a large vacuum leak would also show up in MAF only? BTW, engine has a very small torque type cam and a CAI. Truck actually drives pretty good in MAF only.

thanks

Another try at attached tune

Attached Files
  • 94chev-tune-1-MAF-INITIAL-TUNE-with-reset-to-blended2.hpt
  • Attachments may only be downloaded by paid Gold members. Read more about becoming a Gold member here.

trying logs again

For some reason I can't get my .hpl files to load, any tips on that?

LOL, made a rookie error. I selected a wrong unit of measure when I made the VE histogram. Your lesson was really clear about verifying that the axis info is correct. I am getting a nice VE tune built now.

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