failed smog twice.. need some suggestions

[jeddyminit]

hey guys i took my supra for a smog test twice and both times did not pass. guy says its running rich.
things that i have done prior to the test:
stock intake box and exhaust with both cats
timing is set at 10 degrees
replaced the o2 sensor
vacuum lines look to be correct

my engine was rebuilt less than 10k miles ago, a guy at a local oreilly store recommended replacing the spark plugs
however, a smog tech and professor at my college said that i should run it as is without replacing the plugs. idk what to do there?

btw on the 2nd test that i did, i passed the emissions test at the 25mph test but not the 15mph test

would it matter if i smogged during the day when its warm or in the morning where its still kinda cold?

any input or suggestions are greatly appreciated. Thanks

 

[koldfire08]

Please post your emission readings so we could get an idea of whats going on with your vehicle.

Sent from my SGH-T999 using Tapatalk 2

 

[drew_flux]

Retarded ignition timing and ethanol based fuel *may* help. Does the college you go to have testing equipment?

 

[mkiiichip]

Please post your emission readings so we could get an idea of whats going on with your vehicle.

Sent from my SGH-T999 using Tapatalk 2

+1

Retarded ignition timing and ethanol based fuel *may* help. Does the college you go to have testing equipment?

Umm no. The ignition timing should be checked by the tech, during the test. If its not right, automatic fail.

 

[Nougie]

I failed recently also. The culprit can be anything. I mean that literally. For me, all it was, was the vacuum/hose from the charcoal canister to the firewall/tank? That hose was hard and brittle as a focker!

TIPS
- run the car at minimal 15 mins prior to test
-adding LUCAS/Chevron techron fuel injector cleaner to one full or a third of a tank, burn it all out then Refill prior to test
- do a couple of WOT pulls prior to test
- when u get to the shop, Leave the car on until ur up
-have little to NO vacuum/boost leaks!

 

[jeddyminit]

well guys i failed for the third time today.

heres the report

1st test in november:
brought car back to stock, airbox, downpipe catback


2nd test last week:
replaced o2 sensor


3rd test today 3/13/13:
didnt do much just went on a cold morning


in the second test, i passed the 25mph test after replacing o2 sensor
3rd test today, gross polluter across the board, even at the 25mph test. IT GOT WORSE!

im thinking of replacing the afm sensor, i have a spare that came off of the lexus afm (iirc, sensors are the same, afm housings are just different sizes between 1uz and 7mgte)

 

[CyFi6]

You are running a bit rich there. Are there ANY modifications to the engine or have you put it completely back to stock? Check for codes.

 

[dubsupra209]

Hey did you guys warm up the cars really good? I always drive a lot before I go to the station then leave it idling while waiting for smog.

 

[koldfire08]

Running too rich. I know you replaced the O2 but you still want to check for voltage that would be appropiate for that sensor.
Usually will fluctuate from 0.2-0.8v. A cycle should occur within 1sec iirc aswell.

High HC would usually mean unburned fuel by lack of ignition or incomplete combustion.

High CO usually indicate too rich fuel mixture, also an indicator of combustion efficiency.

What modifications are on the vehicle?

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[jeddyminit]

no codes, no modifications, how would i bring down the HC's and CO's

 

[jeddyminit]

do you guys think that i just didnt run it long enough that the cold start injector was still dumping fuel?

 

[jeddyminit]

oh btw the smog tech and a smog referee had suggested that it could be my ecu? does that sound right?

 

[jetjock]

oh btw the smog tech and a smog referee had suggested that it could be my ecu? does that sound right?

No. ECU is highly unlikely.

do you guys think that i just didnt run it long enough that the cold start injector was still dumping fuel?

No. Doesn't work that way. Could be stuck open though as could one of the other injectors. Checking for rest pressure decay is one way to test for that.

 

[jeddyminit]

well im stuck and dont know what to do any suggestions

 

[CyFi6]

The vehicle is pretty obviously running rich. It is time to do some investigative work and narrow down what is causing it to run rich. There is no easy answer to your question. Your car is pretty far off the charts, no amount of warming it up or fuel additive is going to fix it. You need to do some diagnostic work to figure out the rich condition, there is a multitude of things it could be. If you don't have the knowledge/skills to get into the diagnosis I suggest you take it in to someone who does. There is only so much we can do to help you on here but you need to have some experience and background knowledge with this stuff to be able to solve it, otherwise you are just going to get frustrated with it.

 

[jetjock]

^ Damn well said. I would have said it myself but this place can make one feel like Sisyphus...

 

[3p141592654]

This shouldn't be too hard to diagnose by a competent tech. The car is running 12.3:1, so its clearly not in fuel control. Surprised it doesn't show a check engine light.

 

[A. Jay]

This shouldn't be too hard to diagnose by a competent tech. The car is running 12.3:1, so its clearly not in fuel control. Surprised it doesn't show a check engine light.

+1, Hey OP, does the CEL bulb work?

EDIT: Nevermind I'm dumb, your smog techs would have pointed that out by now.