ECU O2 sensor MODS

[meicalnissyen]

Okay, lets try this again, evaporating post syndrome in effect
I have a 1zzfe and I want to run a 4 into 4, thats right, 4 into 4.
I have a OBX i got real cheap cuz they welded some up backwards, and since I have to get the tig out and scrounge some 304 tube to fix it, well why not have fun ;-)
The issue for me is this, physically, its no sweat 4 baby cats, 4 baby mufflers 4 sticks of 1-1/4 stainless tube, some flange work, and boom all done.
EXCEPT the O2 sensor, If I sample 1 cylinder, and let the ecu drive the other 3 essentially blind, that could be a big problem .
could I get three more stock ecu's and splice the inputs all common, except for the O2 sensor wires inputs which would be dediccated to each cyl and then use the outputs of the three new ones only for there own injector
does that sound feasible??

OR
could I just merge the 4 sensor outputs and feed the stock ECU a blended voltage ?

[QuadCamSix]

If your running NA you will be fine reading off of just one output. The ECU does NOT trim the injectors individually. Try to put the sensor in the output of the 2nd or 3rd cyl since those tend to run hottest and leanest on toyota 4cyl engines.

You are correct that the ECU does use the O2 sensor to detect a missfire in individual cyl's but from what I have read the 1ZZ ecu still trimms all four injectors even if it has detected knock in just one.

Technically you could hook all four O2 sensors togeather in parrallel and the ECU would recive the voltage signal from only the leanest cyl or sensor that is putting out the most voltage. I dont know how equal sensors are from the factory though.

Hope that helps some

Jim

[foodaa]

could I just merge the 4 sensor outputs and feed the stock ECU a blended voltage ?

If all 4 O2 Outputs go into the same Input pin of the ECU, wouldn't the ECU always read the highest voltage? The ECU might think the engine running rich all the time.

You are correct that the ECU does use the O2 sensor to detect a missfire in individual cyl's
I thought the ECU uses the crank sensor to detect misfire. I believe O2 is for fuel trim and for cat monitor.

BTW what's the benefit of doing a setup like this? Why not split the the pipe post cat? Less headaches.

[88 LE]

Cross posting.

Playin with the ECU /O2 sensor

[meicalnissyen]

QUADCAMSIX:
Thankyou verymuch, Most helpful!

FOODAA:
Thanks for the thoughts, O2 sensor would seem to slow to react to misfire.
the reason??? SOUND BABY, SOUND
like a old kaw Z-1 on the cam :-)


88LE:
FUCK YOU

[Tony the Tiger]

Running 4 pipes right out of the exhaust ports = stupid.

I'd suggest hitting some books on exhaust theory.

The entire purpose of a merge collector is to provide the broadest powerband and flattest torque curve possible. A merge collector can increase exhaust velocity at low RPM's and still provide enough flow for high RPM's.

What are you doing basically is saying "I don't need low-end and midrange power"... Meaning your car will lose power a d torque anywhere off idle to 5000+RPM depending on the pipe diameter and lengths you choose.

Scrap the idea unless you want to be slower than stock