2018 Yaris SE 5MT - T-Sport w/Valvematic!

[atomic_hoji]

Quick update: been busy busy with studying for work, but after the last test I took the weekend off to kickback, relax, and actually did a bit of work on the Yaris. Unfortunately, I think the brain marbles as to the troubleshooting I've done on the Yaris have been displaced by studying.

I followed Tom's advice and had a run through the MAF response. Took the car out with my wife driving and had her pull through gears gently, then progressively using more throttle up to basically flooring it in 1st, through 2nd and 3rd. MAF seems to respond as expected. Do find that the values are a little high as compared to the service manual (not surprising there's extra air given the negative fuel trim) but then my idle is a bit on the high side anyway - more on a related, new issue in a minute.. :face palm:

Using my fancy little jig I also cleaned the injectors with carb cleaner, just for the sake of due diligence. It didn't help, but it's done, and it's the first time I've tried it so it was an educational experience, lol.

In a prior job I was a Control Tech and in flow measuring applications where you had short pipe runs and turbulence we would install flow straighteners to help stabilize the flow readings. There are the same sorts of things for automotive intakes - some manufacturers actually use a rough sort of straightener in their intakes. I installed a piece of door screen across the end of the intake (held by the filter clamp) and it brought the LTFT down into the -20% to -26% region - the car will go for a couple of days before the codes pop back on now; PROGRESS! I've ordered an actual flow straightener to fit my intake and I'll have to see if it helps. Also ordered a used, OEM MAF from eBay - I still have a dis-trust of this aftermarket MAF and the used OEM was actually cheaper than what I paid for the aftermarket! Have a couple of other ideas related to airflow as well that I'll keep in my back pocket..

Anyhow, new issue: after clearing the learned values and resetting everything after messing about with the car I now have a revving problem. I've read the Scion iMs have a "rev-hang" issue between shifts, but that's not quite the issue.. When I put the clutch in the revs drop, then bounce up to about 3000 rpm and sit there for about 2-3s, then drop off. I have to stop at a guardhouse on my way in to work and I get looked at funny as to why I'm sitting revving my engine - I'm just waiting to get hauled aside.. lol Now, the embarrassing part: this could be something to do with the injector cleaning or the screen on the air intake (not too bad); it could be because I kicked my ECM across the garage floor on accident (dammit!); or it could be because I disconnected my throttle body while powered (the clue should have been that it was making an electrical whine.. :face palm:)

Ever have one of those days..? lol

OH, on a much better note, I did get my microimage engine bay short shift kit installed. Fits great, and I can now install the block heater as an added bonus. Transmission is nice and notchy now; because #racecar!

-- Adam