Feels like DI isn't kicking in but no CEL

[4n0m41y]

@steve99 @NoHaveMSG

Think I've got it figured out. I fired it up this morning before heading to the parts house. Popped the hood and was examining the di computer. All bolts were tightly fastened. I decided to give the plugs around it a nice jiggle, and Lo and behold as soon as I jiggled the connector in the attached image there was an auditory difference in how it was running, instantly sounded much smoother.

After this I went and grabbed maf cleaner and some carb cleaner for checking vacuum leaks, and while doing so I noticed the issue was much improved. Still a little flat, but definitely better. When I got back I did a datalog of it in this state.

I let it cool down for several hours, then went back out to check for vacuum leaks, all good on that front. I then unplugged the previously mentioned connector, checking the pins, all good, plugged it back in firmly. It's at this point that I disconnected the battery to reset ecu. After re-connecting I let idle for a few minutes, then went on a test run up and down the street. Bingo. She's back! I then did another datalog of this state

Now as you've probably guessed, I don't know what I'm looking at in these graphs. Like I know what the values represent, but I don't know what they should be in relation to each other. It was mentioned that at WOT my afr should be in the high 11s? I see the afr still in the 12s, but the command afr eventually gets into the high 11s. I'm guessing command afr is the value the ecu is attempting to reach, and afr is the actual value?

With all that being said, does the last log I posted seem good or does it indicate that I may still have something going on (even though the issue which lead me to create this thread seems to be resolved)? Still haven't cleaned the maf, but I didn't want to do that quite yet (introducing more variables into the equation and what not).

[steve99]

Ok its looking a little better but still lean top end


Commanded afr is afr the ecu is asking for and AFR is the actual measured afr


If your intake is stock and sensprs working ok then afr and commanded afr should be pretty close like withing 4% or so


Id remove and clean the plugs and sockets on the di computer


Id probably loosen and retighten the three di computer mount bolts as well jist in case there is bit of corrosion and its not earthing\grounding well

[4n0m41y]

Originally Posted by steve99

Id remove and clean the plugs and sockets on the di computer

Id probably loosen and retighten the three di computer mount bolts as well jist in case there is bit of corrosion and its not earthing\grounding well

Going to make this my project for the weekend. I'll remove the di computer entirely, check the contact points between the mounting bracket and computer (maybe wire brush them), clean all plugs, and go ahead and clean that maf. Will report back once all is completed. Greatly appreciate the assistance!

[4n0m41y]

@steve99

Reseated the DI computer bolts, checked all plugs, cleaned maf sensor, reset ecu (by pulling negative from battery). Took it out for a spin and these are the results (got two really good third gear pulls on this log): https://datazap.me/u/ziltoid/004-res...f?log=0&data=1

Driving down low feels solid, mid range from like 4500-5500 seems kinda soggy, and then after 5500ish seems to pick back up a bit. You had mentioned that commanded afr and reported afr should generally be within 4% of each other, so I wrote a script to calculate out that percentage for the log (just to give me some value to look at to be like, yeah that's lean or yeah that looks good) and low and behold from about 4500-5500 she still appears to be running on the lean side.

You think being lean in this range could simply be from needing some adjustments to the default stage 1 oft tune? I had mentioned (I believe) before that my intake was stock...that's basically true, but it might be worth mentioning that I have a perrin intake tube running from the factory air box to the tb, and a k&n filter. Maf is still in factory location and everything. Think that could have something to do with it?

[Ultramaroon]

MAF scaling?