DN1911

my 2001 4Runner recently started to kick insufficient catalyst flow codes. we removed the cats and replaced them with stainless test pipes. and installed a URD 02 simulator. now normally a modification like this results in more power and better if not the same fuel economy. now the problem is, the truck drop way down on MPG. used to get 20, then 18ish when the light started to come on, now 16 MPG. any ideas why or what i need to do?


also there seems to be some type of clicking noise coming from the dash like a relay or check engine light is trying to come on. anyone else experience this with a URD 02 simulator?

cackalak han

I'm sure that O2 simulator would be the culprit. Prob. running too rich?

But seriously, I hope you decide to put the cats back in. Not worth getting caught by the police, harming the environment, or problems like this.

DN1911

i understand the enviromental concern, never said this was lond term.

but i also don't have to worry about police or smog checks in our state at this time.

mt_goat

Any more CELs? Was the original code a P0420?

DN1911

none right now. just an odd faint click noise coming from the dash. truck runs good. as far as the orginal code. all i remember is insuffucent catalyst flow. the guy who scanned it didn't give the number that i remember.

gadget hasn't replied to e-mail i sent him a week ago so i thought i would check here.

Yotacool

you make the test pipe? i want one for my 98 4runner.

DN1911

yes i made them, pulled out the pipes and locked them down in some fixtures, cut out the old cats, welded in stainless tubing to replace them. i can do yours also but you would have to ship the pipe sections to me. the rear one is easy. i just hollowed out the cat and slipped a piece of 2 1/4 tubing through it.

johnw999

I'm sure you've already done this - disconnect the battery and reset the ecu...clean the maf. The only clicking noise that I heard from the dash was when the radio starts the power antenna. I installed the tacoma whip antenna and disconnected the the power antenna wire from the radio. Probably unrelated, but you never know.

Gadget

There are no moving parts in the URD rear O2 sim. There is nothing that can click in it. Depending on how you mounted it, it might be banging around causing a noise.

What you maybe hearing is the relay for the A/C system that will click on and off to controll the compressor clutch.

For your loss of MPG, you may need to remap the fuel curve. You can do this with the URD MAF Sensor Calibrator. It will allow you to correct for any errors you have induced to the ECU's calibration by unstuffing the exhaust. You have likely made it run to lean killing power and MPG.

Gadget

Mrbikerman

Can anyone tell me a manufacturer that can make me a test pipe for my 97 non-cali 5vz?

DN1911

is this difficult to set or adjust for proper air/fuel?

i_love_tacos

ebay has one. search "tacoma test pipe"

so does LCEngineering.com

Mrbikerman

I've only been able to find 4cyl versions for my year.