clarification on tuning.

[ihiryu]

Ok I recently did the lex afm/rc550/safc. I didn't know about the whole VF thing until yesterday. (New to the toyota game sorry.) Anyway so to my understanding is that if I don't mess with the part throttle stuff, the ecu shouldn't relearn the high throttle right?

When you go WOT the ecu switches from closed loop to open loop and reads from the o2 sensor again right?

Also, I read that the ecu pulls a lot of timing so I'm wasting my time to tune after 5500-redline; is this correct?

And finally; when I make adjustments it also effects my fuel cut too right? IE if I add fuel then I'm more likely to hit fuel cut sooner, and if I take fuel, then I'll be adding more room for the fuel cut right?

 

[rumptis]

I'm no expert but the short of it is.

The ECU will attempt to tune its self from 0-70% throttle (Closed Loop), You can verify what the ECU is trying to do by monitoring the VF.

So anything above 70% throttle is (Open Loop) and you will want to tune that by monitoring the Air Fuel.

 

[ihiryu]

wow finally a reply, thanks! Yeah that's what it seems like, if I mess with anything on the low map, I can see vF wigging out. I'm still working on tuning it, it seems the 7m ecu likes to go pig rich too...

 

[CRE]

The ECU does NOT read the O2 sensor at WOT.

 

[ihiryu]

doesn't it go back to OPEN loop on WOT? I've read many post that says it does. And open loop means feedback from all the sensors mainly o2 right?

 

[CRE]

In "closed loop" the ECU tries to maintain a stoichiometric AFR (14.7:1) using the O2 (Lambda) sensor.

In "open loop" the ECU relies on predefined fuel maps and disregards the O2 sensor.

The 7M ECU goes into "open loop" at about 70% throttle and up. The ECU stays in "open loop" at WOT.

 

[ihiryu]

Right, so at WOT i don't have to worry about vF right? Gah since i've left this post alone, I've been searching so i don't sound stupid. I'm so confused about what to do with the safc because of vF.

I've tuned plenty of my own cars with SAFC's, I know how they work and I understand that they are pretty much trimming tools, but this whole vF thing has got me all out of whack, I'm afraid to touch it cause there are so many conflicting ideas on how to piggyback the ecu.