Vortecs, fuel trim and o2 sensors

[GetItBilly]

I'm probably boring everyone by now, but I redid the smoke test and did find a vacuum leak behind the throttle body on a barb that wasn't capped well. Got a new cap and will retest with fingers crossed that it fixed my fuel trims. Also found a bunch of smoke coming out where the dipstick tube goes in the block, so will add that to the list. I ordered new o2 sensors, too, just to try them out. Previous owners said he tried a bunch of different sensors and it always threw the codes but at this point I might as well prove it to myself.

 

[GetItBilly]

Got the dipstick tube inserted, w/ a new o-ring for good measure. I don't think the tube had been inserted all the way into the block since the swap was done. I had to spend some time bending the tube just right to get it routed around the headers. I always wondered why the dipstick read low after I did an oil change.

I don't know what I was doing wrong before, but I've since mastered the DIY smoke machine and found one more leak. My engine is now so air tight that it would probably float. Looking forward to getting new readings.

 

[GetItBilly]

Took the truck for a trip to the store to buy some Regane to dump in the gas. STFT plus LTFT is staying around the +10 mark and there is much less difference in LTFT at idle, 1500rpm and 2500rpm. I think the computer may still be learning since I fixed the vacuum leaks, so I'll continue to be monitoring it. +10 total trim might be about as good as it gets for this 15 year old motor, unless maybe the fuel system could use a cleaning. I'll just have to wait and see.

I swear before I took the trip, I could get the LTFT to jump up a couple points at idle just by closing the hood. I thought maybe it would be changing the airflow, but the MAF reading stayed pretty consistent. I couldn't quite get my head around that behavior, but after the trip to the store, readings seemed to stay pretty consistent with the hood open or closed.