derrick92130

I am running an S/C 3.4 with 305cc injectors and an FTC1 from Split Second. The tuning was all done using the method described all over the forum using the long term fuel trim (LTFT) readings from the ECU.

Does anyone have any info on reading the tables that are maintained in the ECU itself (not those offset tables in the piggyback computer)?

If the ECU maintains a table of the LTFT for each RPM and load, TPS, whatever, then if I were to write a program to read those values directly from the ECU memory, it would make tuning much easier. The current process of basically exercising the vehicle through all possible closed loop permutations to capture the info using an OBDII reader seems to be incomplete and obviously slow.

The idea I have is to make changes to the piggyback, drive the vehicle for a while. Download the complete ECU tables, identify each entry where LTFT is modified by the ECU, update the offset in the piggyback computer, keep driving.

Is my limited understanding/observation of the ECU correct?

Thoughts?

Jeff B. in Michigan

Derrick,

What are you using to determine if the air/fuel is correct?

My opinion = you must have a wide band O2 meter or lots of luck and a 1/4 mile drag strip in your back yard to accurately tune in the FTC-1

I am also using the FTC-1 on my SC 4Runner. I have stock injectors, Kenne Bell BAP and the smaller pulley..... I use a wide band O2 sensor ($349.00) and controller to determine how to set the fuel map in the FTC-1. I just updated my site with details on how it all works... feel free to check it out if you wish

http://N8RWS.COM

Later,

JB

derrick92130

Jeff,

Thanks for the reply and ideas. I am using a WideBand O2 sensor for the A/F ratio logging. I ended up going with the Bosch 6 066 sensor and the TechEdge V2.0 unit. It works very well, and is super responsive.

I read a little on your site and sounds like you are making nice progress as well.

I installed the WBO2 unit just prior to installing the new injectors and was really surprised at how lean I was running at WOT. What are you seeing on yours with the stock injectors?

I have it relatively tuned in, but am use to other vehicles where I can pull data directly from the onboard chip on the ECU and then either alter with a piggyback or overwrite the onboard tables. I know it is a fixed unit on the 4Runner. I am trying to figure out some creative ways I may be able to get at the ECU data (either through creative OBDII calls or potentially pulling the chip from a donor ECU to see how the data is structured on the chip itself). So far I don't know if the dynamic data is stored on the chip or some other memory area within the ECU. It likely is some volatile memory area since pulling the fuse resets the tables.

Let me know how your tuning goes!

ravencr

That's a great idea, but I just don't know if there is such a thing available. The person to ask would be Gadget, probably.

Chris

Jeff B. in Michigan

Derrick,

Good deal on using the wide band meter... have you ever run your truck at the dragstrip? I was hoping to make it to the local track on Friday but they have closed for the season. To date, with the stock pulley, injectors, slipping clutch and BAP set low I have made it down the track in 15.02 seconds.

I just had an ACT 6puck installed on Monday. The shop also installed the O2 bung so my testing is a work in process now. With the smaller pulley and stock injectors, 15 on the BAP and zero change on FTC-1 fuel map I run a bit lean at the top of first and second but just under 12.5/1 all the way through third. Check out the charts here: http://my.net-link.net/~n8rws/TRD10.htm

So far (just yesterday) tinkering with the FTC-1 fuel map & BAP at 10 has provided for flat 12.5/1 all the way through second, third & part of fourth gear. First still gets a bit lean (13.2/1) at the top.

I can get it to run 12.5/1 at the top of first by cranking up the BAP but I go super fat at the lower RPM's... and the top of second and third.

Please let me know what AFR you see with the larger injectors, in particular I would like to know if you notice a trend for the lower gears to lean out at the top but the higher gears run steady.

Thanks,

Jeff B