The "let's brainstorm how to make a piggyback work" thread

[eTiMaGo]

LOF, I posted a second excel file just before your post with more spirited acceleration, Open Loop seems to kick in at 75% throttle and above, though this should require some more testing

I'm not sure you can get injector info off the OBD bus?

But what do you think of that URF AF sensor device I posted earlier? By tweaking the response from the sensor it would have the ability to affect the short term fuel trim and thus richen it up a little as needed. I'm just not sure how the rear O2 sensor will react to that and cause trouble...

[largeorangefont]

Originally Posted by eTiMaGo

LOF, I posted a second excel file just before your post with more spirited acceleration, Open Loop seems to kick in at 75% throttle and above, though this should require some more testing

I'm not sure you can get injector info off the OBD bus?

But what do you think of that URF AF sensor device I posted earlier? By tweaking the response from the sensor it would have the ability to affect the short term fuel trim and thus richen it up a little as needed. I'm just not sure how the rear O2 sensor will react to that and cause trouble...

I saw that log, he is going too slow. We need long WOT pulls in a single gear, like you would do on a dyno.

Injector info is there on the OBD, the software just needs to be able to read it.

The problem with adjusting the fuel trim is that the car will readjust it back. The car can adjust fuel trims around +/- 25% before a CEL is thrown. Like I said, I have never really seen one that truly works. The car is constantly learing around your changes.

The rear 02 does nothing in relation to fueling. It is only there to insure the pre cats are functioning.

[eTiMaGo]

hmmm i believe those are stored values when you have a CEL, not the dynamic values like you've logged so far...

[eTiMaGo]

right right gotcha... well this is way over my head, and I need to get to bed, so I won't be much help

[Nexus1155]

some links i found but im in the process of reading them

http://www.autospeed.com/cms/A_2388/article.html
http://autospeed.com/cms/A_2695/article.html

[aucorium]

hey Guys

FYI , i chatted to a few guys with the SMT6 chip here in RSA, and they werent all that happy with the chip and have since changed to UNICHIP , im not sure if this is isolated senario's but just thought i'd give you guys the heads up.Problems reported are fueling and idiling , but like i said , could just be the cars that were tuned , i will keep an eye out for more info.

[eTiMaGo]

thanks for the heads up, aucorium...

Today I tested something... As you might know I have a basic AF gauge hooked in to the factory sensor, it's not all that useful, but can show me when the car goes to open loop (in closed loop the AF ratio keeps oscillation rich-lean-rich-lean, as this is the most efficient way for the catalyser to work, wile in open loop the needle stays still). So, leaving the house, I shifted up to third at a rather low speed and put the throttle down. The engine was too low in RPMs to gain any sensible speed, but sure enough, AF needle pegged itself at 14:1 after a second, and stayed there until I let my foot off the gas.

I should have a chance to get on the highway late tonight and repeat the experiment in other gears/conditions, but this is quite promising!

[aucorium]

mmm , that seems to show some promise , nice one!! let us know how the test goes.

[aucorium]

FYI

i am busy researching us a Dastek Uni - Q chip , apparently this works on the yaris , it worked on my buddies honda fit 1.5 , so im gonna see if i can get a plug and play setup , as the guys here claim to have one for the yaris , i will keep you posted.

here is the chip:

http://www.dastek.co.uk/features_unichip.htm

it can control VVT aswell !

[eTiMaGo]

here it is in excel format with in-cell bar graphs to show the relations a bit better

http://dl.getdropbox.com/u/691356/FastRun.xls

[lammy29]

any updates after all these years?

[silver_echo]

Originally Posted by PK198105

yes and i did get to play with it somewhat , however it was mainly for maintenance and resetting the ECU. When you first connect the diagnostic computer it asks for tech password and then gives you the option to read, write or reset. i haven't had the chance to play in write mode since i was not allowed to but the tech says when they need to program the ECU it gets either reprogrammed at Toyota factory or they get a brand new one. None of them is able to reprogram the firmware.

is the diag computer handheld based or laptop based? my thinking is that if i can get my hands on the system, i might even be able to get into mine(i am starting the toyota t-ten program soon and with me being in that program, i might be able to spend some time fiddling with the programming), and with the ECU being only slightly different, i might be able to figure it out... my basic thinking was to try to fix the rich condition at WOT, but if i can figure out how to do that, it will open it up for tuning...