piggybacks and obd2

[ImRickJamesBitch]

Here's a question i've been pondering for a bit...

with obd2 in closed loop the engine computer is always trying to keep a/f ratio as close to stoich as possible by using input from the upstream o2 sensor. So... lets say you take your emb and add 10% to the entire injector map, won't the engines computer which is taking readings from the o2 sensor automatically lean the mix up to try and compensate for the added fuel?

can anyone elaborate on this?

[maxgtr2000]

Yes the ecu will still try to maintain stoich in closed loop, you maybe able to get a little bit of fuel by but not consistently. As soon as the narrowband reads rich the ecu pulls fuel. You can disconnect your oxygen sensor(s) the car automatically stays in open loop. You can then tune the afrs for out of boost. The problem is your check engine light will stay on. I'm not familiar with other ecus but the maxima doesn't go into a "limp mode" and change our timing unless the knock sensor was dead so all we get is just a rich afr in open loop.

[ImRickJamesBitch]

so whats the point of tuning with an emb? :p

I live in michigan so no emissions testing in my state:D I was thinking of removing both o2's anyway (my lights been on for months do to a gutted cat popping the downstream o2 code.)

I'm going to be running an innovate lc1 Wideband with the begi turbo kit thats currently being shipped (one more week!) I just wanted to be sure that there won't be any issues with performance by unplugging the upstream o2.

I figure the engine comp will simply run a default map, hopefully not too shitty of one and i'll be able to tune off the lc1 and have the emb in full control of my fueling and timing. Plus, I won't need an o2 clamp!

anyone with a miata care to share some info on this topic?

[Dzaster]

This is where the use of the "O2 clamp" comes in handy. I've used one and it works. There is a thread here where we've gone into. Here it is.

http://www.diytuning.com/forums/showthread.php?t=145

If you've already seen it or it doesn't apply to your car, than disregard.:D

[Accord2nrz]

Your alternative option is to overwhelm the factory ECU by dumping an arse load of fuel. What happens is the ECU can only correct for an estimated 10% in fuel trims...(varies on vehicles) once this limit is reach it gives up. On mine I overwhelmed it too many times after resetting the battery and ECU learned what i was doing. Now my car just decides to keep the car at 12:1 running off the greddy boost sensor. funny huh?

Little tricks but they work.

[Dzaster]

12:1 is the new stoich. lol

Seriously though? So the ECU has accepted it or just some random number that it chose but works well.:confused::confused:

[Accord2nrz]

the ECU accepted it. I know wierd right? but even if I clear out the ecu completely by disconnecting the battery it fires up rich in a cold start and idles to 12:1 and hunts for it while driving. lol

[Dzaster]

And boost? You should start selling Accientally Reprogrammed ECU's. lol

[Accord2nrz]

under boost its hunting for right around 12.5:1. It's crazy and I dunno how I stumbled onto it. I'm heading to a salvage to pick up another ECU or two this weekend and I'm going to experiment to see if I can duplicate what's happened. If so and I can lock down the process we may be onto something here! :)

[yellowpin]

And boost? You should start selling Accientally Reprogrammed ECU's. lol

yes, i agree with you. lol






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