MAF tuning + INJ Tip Temp

[danmw2003]

So I've been attempting to dial in my MAF since I'm a noob and its the easiest thing to start and learn to do. At first I was chasing my tail not watching injector tip temp when making adjustments. I've recently figured out that the Injector tip temp effects fueling, and cause a rich condition after a reflash, until it relearns. Here's what I'm struggling with. I try to log and make adjustments when the INJ tip temp is 120f-130f. It then slowly starts to creep over 130f and eventually over 140f, and then eventually it settles back down to around 128f after driving it for about 30 mins. When the INJ tip temps rise past 135f or higher, it starts to go 5% - 10% lean, until the INJ tip temps eventually come back down from driving it, or letting it sit overnight. Should I only be making corrections once the tip temp hits 135f or so? what is causing it to drift lean when the tip temp rises? I suspect I'm doing something wrong, and hoping someone could point me in the right direction. I suspect I should be making corrections closer to the 140f but not sure.

[dhoagland]

Green Tuner here...
That is designed to compensate for heat soak. Ideally you get your MAF & VVE dialed in when injector tip temp is below correction levels (130 in my case)...

Then you let the heat soak happen, say full operating temp then shut off for 5 minutes or so.
Restart and log injector tip temp and AFR (let it stabilize). Lets say you are at 145 Injector temp tip and running 5% lean then you need to increase the Injector offset vs Injector tip temp until your AFR is correct. Same goes if rich, reduce the offset milliseconds until you are at desired AFR

Obviously hitting all the cells in the table will take LOTS of time and many different situations to create the necessary heat soak.
For me here in TX. In Summer I can let it idle in the driveway and watch the tip temp climb.

For now just concentrate on what you normally see

[danmw2003]

Interesting. So if the offset corrections are causing it to go lean, why wouldn't I just zero out the table completely? I could see making adjustments if it were causing it to go rich, but thats not my case here.

[danmw2003]

I also have to wonder, if some of this would go away once I get my VVE tables dialed in some. I have yet to mess with any of that.

[hjtrbo]

Interesting. So if the offset corrections are causing it to go lean, why wouldn't I just zero out the table completely? I could see making adjustments if it were causing it to go rich, but thats not my case here.

That means it needs more offset. Zeroing it out would make you go more lean. A positive number in this table is an adder to the IPW.

Set a filter up to ignore the higher ITT fuel trim readings on your fuel trim graph so you can concentrate on getting the fuelling right for when your ITT table is not applying any offset. Then hit the ITT offset table later.

[danmw2003]

Oh I see.... I misunderstood what was happening. I thought it was somehow pulling fuel when it hit correction temperatures. My tables show zero corrections below 140, so naturally I thought the corrections above that, were pulling fuel because my EQ ratio is consistent below that temp.

[sgod1100]

Interesting. So if the offset corrections are causing it to go lean, why wouldn't I just zero out the table completely? I could see making adjustments if it were causing it to go rich, but thats not my case here.

yeah definitely DO NOT zero it out. That was "the fix" years ago to just zero that table out to fix the "rich after flash issue". But obviously that isn't the correct thing to do. You can literally just log your stft against your injector tip temp table and see what percentage you have to increase/decrease in the affected areas.

[LS ROB]

how do you set up INJECTOR TIP TEMP vs STFT in the scanner? injector temp vs stft.jpg

[hjtrbo]

The top parameter is STFT. The bottom parameter you can leave blank. Your middle parameter is correct.

[blindsquirrel]

And make sure you add enough decimals - leave it at the default 0 and all cells will show 0. These are very very small numbers. Oh, and the STFT parameter at the top has to be set to Number (), not Percent.

And and... you use the collected data by doing Paste Special > Add... correct?

screenshot.09-05-2022 19.45.45.png

[blindsquirrel]

Anything good or bad about using the LT+ST math instead of plain STFT, if LT's are still active? Or does LTFT need to be turned off?

[GHuggins]

Keep in mind you won't be making corrections to your injector tip temp table using the "paste special multiply" function. You literally just log your trims at correct operating temp while the engine gets to temp and idles there a few minutes, then do a hot reflash and watch to see how far out it is. Also .0075ms doesn't change much. I recommend x.5 all of it and then x.5 from about 85c up and smooth it out from there then begin logging. When everything's right it won't matter if you immediately hot start after filling up at the pump or running back to back hot soak races - fueling should stay the same. So if your bracket racing for instance or just having fueling go all over the place after the motor gets hot - (this on it's own is usually injection timing too).

[LS ROB]

Gentlemen, i really appreciate the info. I'll get the scanner set up and see how this turns out.

[LS ROB]

just wanted to pop in here and say thanks for the help fellers. i found an injector timing excel spreadsheet and used that plus what you guys suggested and man, shes got a little deeper voice now. i wasnt real sure about the spreadsheet but it dont feel like it had any negative effects. once again, thanks!