i have a completed 3.4 swap, runs great but it is stuck in OPEN LOOP wasting gas.

truck:89 4runner
engine: 98 3.4

the codes that are ever present are 120-130-----420 (sometimes).

running one O2 sensor in front, from 89 4runner. none in back. i understand the o2 is either not working or not being recalibrated because the second o2 is missing.

it wasnt a problem til i realized i am struggling under fumes from exhaust, and 11 MPGs.

i can not for the life of me or my buddy find the write up for the DIY o2 sim. Does anyone know the link or person that did the writeup? i looked on the stickies but after 50-75 pages the words and pictures were blurring together.

URD has one for 60 bucks but ehhh kind of expensive

 

I can tell you all about code 420. I have been battling it with my 3.4L 2002 Tacoma for a bit now.

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream oxygen sensor reading should be fairly steady. Typically the P0420 code triggers the CEL (Check Engine Light) if the readings of the two sensors are similar. This is indicative of a catalytic converter that isn't working as efficiently as it should be (according to Toyota specs).

Some common causes are;

-Bad oxygen sensor
-Bad engine coolant temp sensor
-Damaged exhaust components i.e. manifolds, cat, pipe
-Retarded spark timing


--Hope that helps

 

thank you for the help it does help.

I am most-ly looking for the write up for the o2 eliminator black box thing. it replaces the rear o2 sensor like the URD one but can be built from radioshacks over priced parts drawers for around 20 bucks

I have a new high flow magnaflow cat on it, the o2 on the other hand is due to be replaced.

 

It was posted in elvota's swap...

http://www.vfaq.com/mods/O2bypass.html

 

PO125 has been coming on for the last few days instead of the 120&130. :dunno

 

Good link. Saved.

 

thanks by the time i got to elvota's build i was falling off my seat last night. thanks