Percentage LED Display - Duty Cycle maxing out?

On the long list of shit that I don't know what it is or how it's hooked up, to the left of the steering wheel on the dash, there are 2 rows of 10 LEDs. The top one is 6 green, 2 yellow, and 2 red, and has "20% 40% 60% 80% 100%" above each set of 2, so presumably each LED is 10%, etc. The bottom one is air fuel ratio, but it's on a narrowband and sucks, etc., and also stopped working for some reason after I pulled the engine. But that's not the gauge I'm concerned with. An air/fuel gauge without a wideband is utterly worthless.

So, this top percentage gauge. The guy who I bought the car from (Danny) said it was "ignition power", but that doesn't make any sense. My friend suggested injector duty cycle, which would make FAR more sense, and it makes sense according to watching it while driving, to what I expect my injectors to do. However, a few points of concern...

Today, I got the HKS EVC working again (it stopped working after I pulled the engine, musta been loose wires or something) and went off to 205 to do some pulls at real boost with a controller. Wow, so much freaking power this is awesome. Did some 9psi pulls, and noticed the percentage gauge blinking on the first red LED, which means low 90%. However, this doesn't make any sense. Even given that I have very nice intake and exhaust, 9psi still shouldn't be approaching a 90% duty cycle, even on stock injectors, I'd think...

So this brings up the question - what is reading this injector duty cycle? I haven't torn apart my dash yet (it's in process) to figure it out, but does anyone have any idea what it could be reading from? The only thing I can think of is the HKS Super AFR, but I don't even know if that deals with duty cycles or what. I've also been told by a number of people that the HKS SAFR is an utter piece of shit.

So does any of this make any sense? Should I be even remotely approaching 90% duty cycle on 9psi? Is it possible the percentage gauge is something else that increases proportional to throttle and boost...? I'm just confused. I'm worried that I'm going to have to upgrade my fuel system a lot sooner than I thought. I was expecting to have to wait until I was near 15psi to deal with that, much less at 9.

Is this it?



If so, that is an injector duty cycle monitor. Can you get at the wires at the back? If you can check the white wire, use a multi meter to check for continuity between it and the No.1, No.2, No.3, No.4 pins on the ECU. That is where it would need the input from. Or you can check by the ECU to see if anyone has spliced into any of those wires.

I have one on the way to my house. I'm hoping to do some testing on it.

Did some 9psi pulls, and noticed the percentage gauge blinking on the first red LED, which means low 90%. However, this doesn't make any sense. Even given that I have very nice intake and exhaust, 9psi still shouldn't be approaching a 90% duty cycle, even on stock injectors, I'd think...

Click to expand...

Not as crazy as you might think. I have been making this argument for a long time. I have tested the AFM, and even at moderate boost levels, the thing is WIDE open at WOT. So I wouldn't be surprised if you already saw 90% at 9psi. My prediction is/was that the ECU allows you to go almost all the way to 100%, and as a result you run PIG rich from doing it. Every 3sgte I've seen has run off the scale rich, confirming my suspicions. However, you can run run up until ~275whp where it starts to lean out. Of course, you are running at very unsafe duty cycle %'s, which isn't safe either.

Thats basically why I typed up this thread: http://www.celicatech.com/forums/showthread.php?t=1892

Not sure if it is something to worry about or not at only 9psi, but definitely good info to have if that is indeed a duty cycle monitor!

Hah, yeah, that's exactly the thing I have, except it's molded right into the dash pretty slickly. I'll have to take a picture of it as it is in my car.

What exactly is that thing? Do you have any info for it? The guy I got the car from had no idea of anything about it. The A:F ratio part of it's broken right now too for some reason. I'll have to figure out what's up with that. Without any documentation, it's kinda hard to track down...

Yeah, I read that nice huge thread of yours on celicatech. Good writeup.

So, this got me thinking. Seeing as how I have an HKS SAFR, couldn't I in theory switch to 550cc injectors and a bigger fuel pump, adj FR and then start using the AFR to lean out my fuel mixture? The problem I keep hearing you and other people then warning against is that the ECU then advances timing when it thinks it's not as WOT as it is, hence engine goes boom. So, is there any way around this, or should I just save up and get an SMT-6 or something like that.

Starting to run at high injector duty cycle seems like bad mojo, so I'm thinking not to go above 11psi or so until I get a new system for fuel management, since 12psi is going to be where I'm at like 100%, and that = bad. 5psi = ~50%, 10psi = like 85%, so I'm just guessing.

With the stock topmount ST185 IC and the spad fan blowing on it, I'm thinking even 12psi is probably a bit aggressive anyway and that I really shouldn't go over 10 or maybe 11. Right now my HKS EVC IV is set to 10psi high and 7psi low, and I plan to run low most of the time unless I want to have some fun. Getting on the highway at 10psi was some fun as all holy hell though. I got to 90 before I even realized how fast I was going.

So, I think I'm going to hold power around here until I get to the next stage of upgrades, which will be fuel management, CT20B, and ST185RC or ST205 intercooler and then run 15psi high/10psi low. That's going to be pretty ridiculous, I think. Gotta wait til I have the 1.5-ish grand for that round though.

Cool, I'd like to see how it was mounted.

This is all the documentation I have on it: http://www.efisystems.com/af_monitors_narrow.html

Yeah switching to the 550's is possible...but its probably pretty dangerous depending on how much fuel you are taking out, at what RPM/Load sites. I am preparing my car to install them right now, however I will be removing timing with the SMT6.

I've seen a few people get away with it. Some do the majority of the tuning with an adjustable FPR, and then make small adjustments with the SAFC/SAFR in the low load areas. So yes it is possible, but not everyone is so lucky that their engine survives it.

The amount of boost is up to you really...if you want to run the high injector duty %'s, then 12psi is fine and dandy. Most people get away with that for a long long time. The good thing is that you are probably running so rich that any little inconsitency in your A/F won't make a bit of difference.

I've run 14psi on the CT20b, and I KNOW I've hit very high duty cycles, but I've been extremely careful to watch the gauges while doing so. I've got a lot of gauges to help me.

Chris

This is how it's mounted.



Kinda nice. Except that it's rather hard to get myself to even glance at the injector cycles when I'm busy flying down an onramp at 10psi. That's true of any gauge though, I'm finding.

i woudl definately back chris up when he is saying that despite 9 psi being within the limits of fuel cut the car will still run rich... i beleive it to be that toyota wanted the car to run very rich for reliability issues... so yes you should have more room to run higher boost (i ran 15psi with everythign stock for quite some time with no worries) but i dont think there is much you will be able to do with the duty cycles with the stock ecu

i like the way that gauge is mounted though... pretty sweet

Thats a slick set up.

Yeah basically running so rich will protect you from the high injector duty cycle for the most part. 9psi is definitely fine. This is another reason why RickyB's power primer is flawed. He is basically telling you to increase the duty cycle even more! (when you do the FPR/SAFC trick)

Hopefully soon I'll have some data on the absolute maximum that the stock ECU will allow. We'll see if it will get up to 100%. After that is done, the stock injectors are getting ditched along with the AFM.