CA Smog: Diagnosing ultra rich condition

[BigKO]

Hello all,

I recently went to have my car smogged at a test only station and had some enlightening results.

First :
I have no codes. Checked before and after the smog test.

Second:
I'm running pig rich, which I believe is causing very high Carbon Monoxide and Hydrocarbon readings. As far as I can tell the car idles and drives fine. I am guessing I'm losing some power, but there is no hesitation, etc.



My Plan:
I first plan to check my O2 sensor here: http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=119

Does anyone have any other/better suggestions? Does anyone know why I would be running so rich without any codes appearing? I also suspect the Air/fuel regulator, and my O2 as a hunch, but have no evidence to back it up.

EDIT: Fixed image.
EDIT2: I recently disconnected and installed a new filter. If I remember correctly, the ECU needs to "relearn" after the battery is disconnected?? Could this be a potential contributor? Please note, there were no codes before the battery disconnection either.

 

[jetjock]

Actually, it should run pretty well with those numbers since best power is richer than stocih but yeah, the engine is obviously not in fuel control. That said those O2 readings are a little screwy. Under those conditions they should be near zero. Might be a little misfire going on in addition to fuel control. Btw, know why these cars have long been Test Only in Cali? Because they have such a dismal failure history...

 

[BigKO]

Actually, it should run pretty well with those numbers since best power is richer than stocih but yeah, the engine is obviously not in fuel control. That said those O2 readings are a little screwy. Under those conditions they should be near zero. Might be a little misfire going on in addition to fuel control. Btw, know why these cars have long been Test Only in Cali? Because they have such a dismal failure history...

Thanks for the reply jetjock. I've heard the saying used before "[..] engine is obviously not in fuel control.", but I'm not exactly sure what you mean by that. Do you mean the engine is outside of correctable Vf levels, or that fuel control is not being done?

Yes, I noticed a slight misfire at idle but it wasn't there 7 months ago when I parked it. I thought maybe it was old gas, which probably isn't best for a smog test either.
I can totally believe the fail rate. It's likely 1 part modification failure 1 part failed tests...

 

[jetjock]

The engine is in fuel control when the O2 sensor is adjusting injection duration to maintain an average stoichometric mixture in the exhaust stream. The further away from this mixture (14.7:1) the exhaust stream is the poorer is catalyst efficency. A little Googling will tell you more.

Your engine is so far out of whack the problem should be easy to find. Check the O2 sensor for cross counting per the TSRM. Also check fuel pressure, rest pressure, and read up on how to use Vf and OX. Course, you'll need a decent DMM for that. The O2 sensor can be checked in situ by forcing the engine lean then rich or off the car using a propane torch.

The car has a dismal failure rate for basically one reason: it's modified and messed with by people (mainly kids) who have NFI what they're doing and that comes back to bite them during emissions testing. Unfortunately that effects all owners.

 

[BigKO]

Thanks for the rundown.

I understand the basics of the stoichometric ratio, and I'll assume you mean proper fuel control just isn't happening(Which I should point out is obvious). I've got a fair DMM, by no means high end... it should get the job done.

I'll diagnose the O2 sensor as soon as I can, as well as check fuel pressure etc. I've read some articles on Vf before, not so much on OX, I'll definitely give myself a refresher. I'll report back as soon as I finish the 02 check (Don't hold your breath, I'm slow), I like the propane torch idea. Simple yet effective.

 

[jetjock]

A stoich feed gas into a healthy catalyst is what's needed. Unfortunately, since improper feed gas composition can render a cat useless, you may need a new one and with Cali's latest rules that can be a hassle. It's why one should never ignore problems even if the car is running OK. It's also why a cheap NB sensor display is worth more than people give it credit for because, lacking a WB, it allows quick verification of closed loop operation.

 

[Nick M]

As far as I can tell the car idles and drives fine.

"Rich" is easier to light.

 

[BigKO]

A stoich feed gas into a healthy catalyst is what's needed. Unfortunately, since improper feed gas composition can render a cat useless, you may need a new one and with Cali's latest rules that can be a hassle. It's why one should never ignore problems even if the car is running OK. It's also why a cheap NB sensor display is worth more than people give it credit for because, lacking a WB, it allows quick verification of closed loop operation.

California's smog laws are extremely stringent. It's a hassle, the system is game-able and it costs the average driver a ludicrous amount of money... but I do respect an attempt to improve air quality. Especially in crowded southern California.

That being said, it's very likely I'll need a new cat with all that fuel being dumped into it. Not something I'm looking forward to purchasing, but it is what it is.

I do have a wide band meter that I've been wanting to install and may do so after o2 diagnosis to check my afr.

To be honest other than a dyno I did previously that showed a super rich higher rpm range(low rpms were ok) this is news to me

 

[BigKO]

"Rich" is easier to light.

I guess 10:1 isn't enough to do it, but after seeing these results I was surprised I wasn't bogging at lower rpm. My intuition was wrong lol

 

[BigKO]

Just for shits and giggles here is an updated pic of my car:

 

[jetjock]

Yeah, Cali emissions suck big time, along with so many other things in that crap hole of a state. It's why I left. You should too. The only way to kill that beast is to stop feeding it.

Couple more points:

1) The engine only runs in fuel control during steady state part throttle conditions.

2) The MIL should have come on. After all the entire point of OBD (first developed and mandated by California)
is to monitor emissions and let the driver know when they exceed 1.5 times the federal standard. Assuming you're running the stock ECU I can think of a couple of codes that should have been set.

 

[BigKO]

Yeah, Cali emissions suck big time, along with so many other things in that crap hole of a state. It's why I left. You should too. The only way to kill that beast is to stop feeding it.

Couple more points:

1) The engine only runs in fuel control during steady state part throttle conditions.

2) The MIL should have come on. After all the entire point of OBD (first developed and mandated by California)
is to monitor emissions and let the driver know when they exceed 1.5 times the federal standard. Assuming you're running the stock ECU I can think of a couple of codes that should have been set.

My thoughts as well. I went to Oregon for 6 months this last year for work, and there is a stark contrast.
1) Good to know
2) My thoughts exactly. I checked them before leaving for the smog test, and immediately after returning and nothing was set. I expected maybe a code 21(Oxygen sensor signal), or code 24(AIT signal), a 26(air fuel rich condition) definitely should have been set, 31/32 (AFM signal) is a possibility, etc. I was rally puzzled to see that nothing popped up given the host of possibilities.

Quick Question: Could damaged feed or return lines cause such a condition? Say returns not working properly, so it dumps to exhaust instead of properly returning to the tank?
To answer your question, yes I'm running the stock ECU. I only have bolt on modifications: K&N CARB legal intake filter, intercooler and piping, legal on turbo cars, and exhaust.

 

[jetjock]

.... Could damaged feed or return lines cause such a condition? Say returns not working properly, so it dumps to exhaust instead of properly returning to the tank?....

Sure. A pinched return would cause high fuel pressure. That's why I said to check it. More likely though an injector (including the CSI) or the fuel regulator is leaking which is why I said to check rest pressure. You have to start somewhere and go methodically through each system. First would be the O2 sensor though. It can be hard over because it's dead or because something else is driving it hard over. You must first decide which is the case because the sensor not only needs to work for fuel control but also because it's valuable as a troubleshooting tool.

 

[KKZ SupraMan]

You could just to what the american cars do and pump fresh air in the exhaust with an air pump lol but i would start with converter and teplaace o2 sensor

 

[BigKO]

Sure. A pinched return would cause high fuel pressure. That's why I said to check it. More likely though an injector (including the CSI) or the fuel regulator is leaking which is why I said to check rest pressure. You have to start somewhere and go methodically through each system. First would be the O2 sensor though. It can be hard over because it's dead or because something else is driving it hard over. You must first decide which is the case because the sensor not only needs to work for fuel control but also because it's valuable as a troubleshooting tool.

That's the plan. O2 sensor fist, and then fuel system.

 

[BigKO]

Sure. A pinched return would cause high fuel pressure. That's why I said to check it. More likely though an injector (including the CSI) or the fuel regulator is leaking which is why I said to check rest pressure. You have to start somewhere and go methodically through each system. First would be the O2 sensor though. It can be hard over because it's dead or because something else is driving it hard over. You must first decide which is the case because the sensor not only needs to work for fuel control but also because it's valuable as a troubleshooting tool.

That's the plan. O2 sensor fist, and then fuel system.

 

[BigKO]

You could just to what the american cars do and pump fresh air in the exhaust with an air pump lol but i would start with converter and teplaace o2 sensor

http://i0.kym-cdn.com/photos/images/newsfeed/000/173/576/Wat8.jpg?1315930535

 

[Nick M]

Yeah, Cali emissions suck big time, along with so many other things in that crap hole of a state. It's why I left. You should too. The only way to kill that beast is to stop feeding it.

He is just a leisurely drive from Vegas.

 

[jetjock]

Yep, but only temporarily. Too desolate for my taste. Still beats living under the iron fist of the Caliban though.

 

[KKZ SupraMan]

Yep thats one thing your boy Arnold should of fixed how did he get elected anyways did he push all the houses into the ocean and the save the babies
http://i0.kym-cdn.com/photos/images/newsfeed/000/173/576/Wat8.jpg?1315930535 《-- nice touch here i figured i would use it too lol