Smog inspection, Help!

[3p141592654]

Cygnus has most of what you need. Its for a 90, but besides some connector changes the ECUs are effectively the same from a debugging perspective.

The Vf signal is accessible right at the diag block under the hood, as is the O2 signal. Vf is basically equivalent to long term fuel trim in OBD2 language. It tells you if the ECU thinks your engine is behaving within normal parameters.

Here is the procedure
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=119

Sounds like the temp sensor is ok based on your post. It should idle around 650rpm hot with accessories off. If higher, then the sensor could be an issue.

Did you check the plugs?

 

[jerry12345]

Cygnus has most of what you need. Its for a 90, but besides some connector changes the ECUs are effectively the same from a debugging perspective.

The Vf signal is accessible right at the diag block under the hood, as is the O2 signal. Vf is basically equivalent to long term fuel trim in OBD2 language. It tells you if the ECU thinks your engine is behaving within normal parameters.

Here is the procedure
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=119

Sounds like the temp sensor is ok based on your post. It should idle around 650rpm hot with accessories off. If higher, then the sensor could be an issue.

Did you check the plugs?

 

[jerry12345]

Too many "honey do's" today.Will get to the plugs tonight.
Thanks

 

[jerry12345]

Finally pulled the plugs and they have a nice coat of loose soot on the base of them. While I was removing the plumbing from the top of the engine I did find a loose clamp between the 3000 crossover pipe and the intake. I wiped down the plugs and put it back together hoping the clamp was the problem. It seems to run much better now, but my tail pipe tells me it is still too rich.
I think tomorrow I will run through the pages you referenced in the TSRM referring to the EFI system. That seems pretty straight forward. If that all comes out I guess I will de-plumb it again and go after the cold start injector. Sound like a reasoable plan?
Thanks, Jerry

 

[jerry12345]

What I forgot. By the way, I do know how to spell "reasonable". it just doesn't look like it in my last post.
Anyway, after I put it together this afternoon, I stuck a vacuum gauge on it. Warmed up and idling at 650rpm it showed a rather nice 20" of vacuum. Something I did notice though when playing with the Climate Control switches is that If I select upper level or lower level heater vents, it does not seem to switch completely. That is if I select floor vents, there is still quite a bit of air coming from the face level vents. Is that normal? Or, do I have an under dash problem also?
Thanks again,
Jerry

 

[thechori]

i'm having the same exact problem, but it's on my 89 N/A, the car didn't pass about 4 days ago and i've been noticing ALOT of dark dustish stuff at the end of the exhaust pipe.. will definitely keep a look out on this thread, gl with your problem

 

[jerry12345]

What I forgot. By the way, I do know how to spell "reasonable". it just doesn't look like it in my last post.
Anyway, after I put it together this afternoon, I stuck a vacuum gauge on it. Warmed up and idling at 650rpm it showed a rather nice 20" of vacuum. Something I did notice though when playing with the Climate Control switches is that If I select upper level or lower level heater vents, it does not seem to switch completely. That is if I select floor vents, there is still quite a bit of air coming from the face level vents. Is that normal? Or, do I have an under dash problem also?
Thanks again,
Jerry

 

[jerry12345]

Please disregard the questions about the heater functions. I believe that the only time vacuum is used is for the water control valve and all of the under dash switching is accomplished by electrical servos. Correct?

 

[bwest]

here is some info on monitoring VF, which will help you see how 'rich' the car is actually running.
http://www.supramania.com/forums/showthread.php?t=4668&highlight=vf

more info with a more detailed explination:
http://www.mkiiitech.com/forums/viewtopic.php?t=593

 

[3p141592654]

Sounds like a good plan. With all plugs showing rich its something common to all cylinders.

If the CSI is leaking you would expect Vf to show 0V (engine running rich and ECU reducing fuel to the injectors to compensate) and the O2 sensor is probably hard over on the rich side and not counting.

Your intake leak would make it run lean on vacuum such as idle and off boost.

 

[jerry12345]

Started on it today and decided to do some cold checks first. The first item I went to was the coolant temperature sensor. That seems to be way out of tolerance. Ambient remp around 50 degrees and it measures 36 ohms vs. 2-3k.. At operating temperature it only comes up to 72 ohms vs 200-400 ohms. I think I better replace that before I go a lot further. It is locally available and cheap. That is my kind of part! The question is of course will this variance be the sole cause of my problem?

 

[jerry12345]

Been out of the loop for a couple of days. My optimism regarding the coolant temperature sensor was a bit premature. So far I have not been able to find one. NAPA and Kragens have what is supposed to be the correct ones but they are no where near the correct physical size. Guess I am bound for the dealer tomorrow with my wallet in hand.
Just for the fun of it though I visited a couple of junkyards with my ohm meter. Found several N/A cars with a temperature sensor that reads the same resistance as mine. Does that sound normal or did someone install the wrong one in my car?
Thanks one and all and wish me luck.

 

[CBLEGUY]

You might want to test the impedance of the CSI time switch. if the impedance is bad, your time switch could be telling the computer that the car is cold.. the sensor is locate on the top of the water outlet pipe.

 

[jetjock]

Even if the thermo time switch was bad it and CSI only receive power when the engine is being cranked. There would have to be a very specific type of wiring problem for them to be energized any other time. Highly unlikely. That said you meant resistance. DC circuits do not have impedance.

Jerry: Trust me, as someone formerly Cali smog certified who still does it on the side I can say that unless you take the car to someone who has the right gear and knows what they're doing you're looking at a very frustrating future.

 

[jerry12345]

Jetjock,
I do believe you are right. Going the commercial route will probably be the way I solve this problem. In the meantime though, I am learning a hell of a lot about the car. Not quite ready to give up yet, but I can see it in my future. Got some more tinkering to do.
Thanks,
Jerry

 

[jetjock]

Too bad Elk Grove is so far away or I'd give you a crash course on this stuff while fixing it for you. The problem is your car is only slightly out. Gross polluters are easy to fix but problems like yours can be tricky. Emissions aren't all that difficult but they're specialized repairs requiring knowledge and gear most DIY mechanics refuse to learn or buy. Why that is has always puzzled me since the knowledge and gear can be used to resolve so many other problems. Anyway, imagine repeatably failing the test no matter what you do. That's very likely what you're facing so the money you pay a competent emissions tech would be worth the hassle factor alone.

 

[jerry12345]

Going back for my free re-inspect tomorrow. If it fails, there is one place in town that has a very good reputation and backs up their work. They are next if needed.
Thanks,
Jerry

 

[jerry12345]

I am now officially between a rock and a hard place.
Failed smog miserably yesterday. HC went upt to 204(@15mph) and 220 (@25mph) and CO went up to 1.81 (@15mph) and 2.17 (@25mph).
The shop that will guarantee a pass just wants to put on a new and larger catalytic conv. I talked yesterday with a good smog guy and he told me it would probably make it pass but it was like a bandaid.I believe he knows of what he speaks. I don't want to do it if I can't get it right.
I have absolutely eliminated the cold start injector leaking as a cause. I picked an old one up at Pick and pull and hooked the fuel line to the cold start to the dummy one that is hanging outside the intake. Seems like the O2 sensor is working, the voltage on the lead from the sensor reads about .025 at idle, goes up to .87 at higher rpms and then sets back to .025 at idle.
Tried disconnecting the Mass Air Flow sensor. The idle picks up slightly but as soon as you give it any throttle, the engine dies completely. I suspect that is as it should be.
Measured resistance on the Air Flow Meter. Between E-2 and THA was at 2500 ohms at 60 something degrees. Seems okay. The measurements between KS and E1 terminal come out art infinity and 7k ohms. The one that is kind of troubling is the VC-E1 terminals. They came in kind of low at 7k and 2k ohms when reversed. Is this much variance normal?
Went over all of the vacuum/boost hose connections. Cannot find any leaks, even with ether.
Any more advice please.
On another note, is it possible to buy a reasonably priced meter that will read out HC and CO levels? I bet not.
Thanks again.
Jerry

 

[jetjock]

Jerry, sorry to say but I'm not the least bit surprised. The car is still rich. Yes, a new cat might pass but your guy is right: it's cheating and only masks the real problem, which will come back to haunt you.

The CSI was not likely to be at fault.

The O2 sensor reading is not correct. I suspect even if it were correct what you're using to measure it is not up to the job. With what you probably have it's best to use Vf instead.

The AFM is also unlikely to be the problem.

You'll need more than a 2 gas analyzer to resolve this. All it'll tell you is a bit of what you already know. What it won't do is tell you how to fix it.

In spite of requests you still haven't supplied codes or Vf data. It'd be nice to know that stuff.

I feel for you and I'd like to help but it's obvious you have neither the gear nor expertise to resolve this on your own. Again, if you want to avoid a lot of frustration you'll need to pay a good emissions tech. Anyone who suggests putting a new cat on isn't one. You could always pay for the wavier. It's $450 as I recall. A good tech could probably fix it for less though.

 

[3p141592654]

If it was me, I would still follow up on a few loose ends before going to a pro. First, the O2 sensor should be counting at idle and cruise. That is, the signal should be oscillating between rich and lean. It should fluctuate 8 times or more in 10 seconds per the test procedure outlined here.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=119

Since you replaced the timing belt, it is possible that the cams or the ignition are out of time. I would double check that as well. Hopefully you checked the compression when you did the belt and the engine is mechanically sound.

Please do tell us the Vf reading as well.