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

[CrankyOldMan]

Originally Posted by atomic_hoji

I had the epiphany that the iM demands fuel pump by duty cycle, but the way I've got it setup it is ignoring the duty cycle request and always giving 100%; the ECM asks for x% and the system is ramming 100% to the injectors all the time. Made sense to me anyway..
-- Adam

Makes sense to me that it's pulling fuel then. It's getting too much fuel for the expected injector duty cycle.

[atomic_hoji]

Originally Posted by CrankyOldMan

Makes sense to me that it's pulling fuel then. It's getting too much fuel for the expected injector duty cycle.

At least if I'm wrong the problem had us both duped?!

Here's a plot from when I had Techstream running on the weekend.. The Fuel Pump duty request was only about 75% (scale labels are goofy) most of the time - only jumped up to about 90% when I jumped on the throttle some. STFT is all over the place, not surprisingly, but does average out to around 0%'ish... sort of... LTFT (not shown, doesn't change much like STFT) was still -30%, but did jump up and down some. Used a reset Utility to clear all the learned values; even though I had the battery disconnected while I was doing wiring repair, the LTFT was still way off. I'm sure a bad learned value isn't helping the cause.

TS-2ZR_run.jpg

Have queries in to a couple of online places to see what the price new is for a Fuel Pump Control ECU is; will also need the connector, which is ~$10 or so, and hope I have terminals to use with it.. if not, it's time to Hodge Podge Bodge the bugger.. In all honesty, I think proper FPC should help sort out the fuel trim. Was hoping my clever fuel pump bypass had solved the problem, but seems like it will just end up running overly rich and likely have terrible fuel economy if I leave it this way.

Also dropped the exhaust and notched the flange where it was rubbing the body - not perfect, but a dramatic reduction in the nasty vibration when steering left. When I drop it again to weld the repair piece in I'll round out a bit more off the flange and see if I can 'clearance' the tunnel slightly - yes, I mean use a hammer...

-- Adam

[CrankyOldMan]

Originally Posted by atomic_hoji

At least if I'm wrong the problem had us both duped?!

Here's a plot from when I had Techstream running on the weekend.. The Fuel Pump duty request was only about 75% (scale labels are goofy) most of the time - only jumped up to about 90% when I jumped on the throttle some. STFT is all over the place, not surprisingly, but does average out to around 0%'ish... sort of... LTFT (not shown, doesn't change much like STFT) was still -30%, but did jump up and down some. Used a reset Utility to clear all the learned values; even though I had the battery disconnected while I was doing wiring repair, the LTFT was still way off. I'm sure a bad learned value isn't helping the cause.

Have queries in to a couple of online places to see what the price new is for a Fuel Pump Control ECU is; will also need the connector, which is ~$10 or so, and hope I have terminals to use with it.. if not, it's time to Hodge Podge Bodge the bugger.. In all honesty, I think proper FPC should help sort out the fuel trim. Was hoping my clever fuel pump bypass had solved the problem, but seems like it will just end up running overly rich and likely have terrible fuel economy if I leave it this way.

Also dropped the exhaust and notched the flange where it was rubbing the body - not perfect, but a dramatic reduction in the nasty vibration when steering left. When I drop it again to weld the repair piece in I'll round out a bit more off the flange and see if I can 'clearance' the tunnel slightly - yes, I mean use a hammer...

-- Adam

What about swapping the fuel pump itself for one that doesn't use PWM? I'm not sure if the previous gen Yaris uses a fixed rate pump or not, but none of the 2ZR-FE swaps have the same fuel problem.

[atomic_hoji]

Originally Posted by CrankyOldMan

What about swapping the fuel pump itself for one that doesn't use PWM? I'm not sure if the previous gen Yaris uses a fixed rate pump or not, but none of the 2ZR-FE swaps have the same fuel problem.

Mm.. I don't think my Yaris fuel pump is the issue. Looks like all Yaris - older and current - all use fixed ON/OFF fuel pumps. The ECM detects IGN and crank motion, grounds FPC terminal to energize the C/OPN relay and the fuel pump runs - nice and simple. My Google-fu finds the 10th gen. Corolla and xD use this same fuel pump control method, hence why in those swaps the ECMs worked without issue with the Yaris fuel pump setup.

Why I'm running into problems is that 2014+ systems have this fuel pump control ECU that receives the ECM duty cycle output signal and controls power to the fuel pump motor. The ECM must be programmed with injection pulse widths expecting that the fuel pump flow is corresponigly reduced as the ECM is requesting on the FPC output. Where-as my Yaris fuel pump flow is hardwired to run ON/OFF style, so when the ECM is for example set to open the fuel injector for # ms and is requesting 77% fuel pump flow, what is happening is the injectors open for # ms with the fuel pump at 100%; the AFR detects it's way rich and pulls the fuel trim to meet target air:fuel.

Or at least that's how I understand it..

Have a fuel pump control ECU ordered with the associated 6-pin connector. Having to bring it in from the California warehouse he said, so could be a bit to get it across the border and out to me. I'll run thr FPC wire this weekend, I think. And see if my 1.75" exhaust tube comes in tomorrow - the truck's muffler has been broken for months, so I've become kind of used to exhaust noise.. lol

-- Adam

[ArmstrongRacing]

Originally Posted by atomic_hoji

At least if I'm wrong the problem had us both duped?!

Here's a plot from when I had Techstream running on the weekend.. The Fuel Pump duty request was only about 75% (scale labels are goofy) most of the time - only jumped up to about 90% when I jumped on the throttle some. STFT is all over the place, not surprisingly, but does average out to around 0%'ish... sort of... LTFT (not shown, doesn't change much like STFT) was still -30%, but did jump up and down some. Used a reset Utility to clear all the learned values; even though I had the battery disconnected while I was doing wiring repair, the LTFT was still way off. I'm sure a bad learned value isn't helping the cause.

Attachment 59635
:

-- Adam

The graphs look somewhat normal to me. The only thing that looks strange is at the end where you start stabbing the throttle. It’s proving feedback on the first stab but then it just starts reading a full rich condition. That tells me either it went into Open Loop or you A/F sensor is not reading properly???

[atomic_hoji]

Originally Posted by ArmstrongRacing

The graphs look somewhat normal to me. The only thing that looks strange is at the end where you start stabbing the throttle. It’s proving feedback on the first stab but then it just starts reading a full rich condition. That tells me either it went into Open Loop or you A/F sensor is not reading properly???

That's good to know, thanks. Getting into fuel trims and some (most) of this stuff is new ground for me, so nice to know what's normal.

Unfortunately I don't recall what I was doing when I did the run, though looks like accelerating and shifting under mid-throttle - seems about right..? I have checked the AFR resistance and it was in spec, but ya maybe the AFR is mis-behaving or something related is tripping the ECM up and going open loop. Going to try some more troubleshooting once I have the FPC ECU installed - which is on order and was able to pick-up a 2000 mile unit off eBay for about half the price.

-- Adam