Let me begin this post by stating that I might have made some by-chance observations that worked, but in no way am I an injector pro or would I ever claim to be haha. That being said, you may keep reading.
Not too long ago I got the chance to tune a truck with Ford Racing 42lb/hr injectors on it. I knew it was going to be interesting and likely frustrating trying to tune the injectors as well as the idle airflow for this motor. The way I’m going to writeup my own little “how-to” for Ford 42’s might not technically be the “correct” way, but it solved all the issues I had with getting the motor to behave at idle.
Most of my general knowledge about injectors and what to tune for came from RedHardSupra’s blog. I give Marcin credit anywhere and anytime that I can because honestly I most likely would not have learned as much if it weren’t for his blog. I never kept track of the hours I spent trying to understand his air mass model calculations for a reason. One could imagine/realize the brain frying that went on attempting to parse out anything that made sense into the wee hours of the morning.
The writeup will focus on Ford Racing 42’s on a ‘06 PCM. I’m positive the same methods can translate over to different flow-rate Ford injectors, but some of the injector value tables within HPTuners might be different between another OS.
I got around to writing up the how-to, here’s the link
2 Comments
Fantastic write re calibration of 42lb injectors for GM application.
I was wondering by changing the offset voltage as per your recommendations and re-tuning the VE table, would it cause a loss of power, or should I expect to see the same rwkw.
I was down 35 rwkw, after changing the offset and VE table.
I suspect that I have other issues and not the injectors.
Thanks
Hi Con, recalibrating the VE and MAF tables should only compensate for the change in fuel flow with the Ford injectors compared to the OEM injectors. You shouldn’t see a reduction in power at all since you’re just increasing the capacity of your injectors. Have you logged your air/fuel ratio with a wideband since the injector swap? I’m assuming you have, but just checking. Are you using a dyno to figure horsepower or are you using the trans input torque PID from the computer? Using a dyno is the only real way to see what power you’re putting out. The input torque PID uses a number of airflow tables to calculate torque input based upon total airflow and commanded fueling. Somewhere on the HPTuners forums there is a detailed description on the calculation, but in a nutshell it’s not very accurate if you’re anything beyond stock-like airflow. For instance my “calculated” trans input torque from my PCM reads out around 350 but I’m actually putting about 350 trq to the ground. Anyways, if you want to email me a log of the car I could look at it to see if there’s something obvious.
Thanks!
Jake
tunedbyjake@gmail.com