I just installed Vortec heads on my 350 GMC Jimmy. I have the 7427 PCM and started working with the BJYL mask. When tuning my VE tables, how do I tune for greater than 100% VE?
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I just installed Vortec heads on my 350 GMC Jimmy. I have the 7427 PCM and started working with the BJYL mask. When tuning my VE tables, how do I tune for greater than 100% VE?
You don't. Have you viewed your datalogs and looked at your injector duty cycle? You will need approximately ~75lbs/hr +/- of injector to feed the engine with a decent max duty cycle. You can increase your fuel pressure and set the new flow rate in the bin. You will have to then retune your VE .
Ok Great! I was hesitant to change the fuel rate after I upped the fuel pressure because I thought it wouldn't change the VE tables.
What i did was put the heavier spring in to up the fuel pressure, then retuned the VE tables without changing the lbs/hr in the bin file. Is there any consequences to doing it this way?
Thanks!
The pcm relies on fuel rate to calculate pulse width for fueling. There are calculators out there but the formula is sqrt (new pressure / old pressure) X old flow rate = new flow rate . You will have better results after changing your fuel rate in the bin.
HTH
Brian