failed emissions this morning.

[Buzz]

If you find it is that cat, and need to replace it, don't leave it in all the time. Have an exhaust shop build a test pipe for you, tell them it's to put in while drag racing or something. The test pipe bolts into the spot where the cat goes normally. It's just a piece of straight pipe. At the performance shop I worked at for a long time we found that aftermarket cats barely last the two years in between tests if you leave them in. I use one in my '91 Jetta. About a week before testing I throw it in, drive it normally, go through my test and then put the test pipe back in. Then, I store the cat until the next test.

While I agree with your point that aftermarket cats are short lived compared to an OEM cat (which I had highlighted earlier), running your "test pipe" (i.e. no cat) in between E-Test periods is a very unenlightened suggestion.

You are probably too young to remember what parts of California were like in the 1960s and 1970s - the smog was simply awful. Thankfully technology has come a long way since then, and today we have engines producing anywhere from 500 to 700 HP, while still using the OEM cats, and meeting their model year emissions requirements - which are more stringent than the 1992 model year emissions this gentleman must meet.

Removing the cats from vehicles, given the current level of technology, is simply a fool's errand. It is irresponsible actions like these that bring about increasingly restrictive legislation that impacts us all. Every Hot Rod that goes out the door of my shop is equipped with a pair of high quality cats - even if the vehicle is from the 1930s.

[EagleMark]

One of these days the EPA will realise that everyone on the internet has been removing cats and all hell will break loose as far as enforcement. We will all pay!

CAT Convertors do wonders for our air and barely effect HP, so why remove them?

The only time I recommend removing them is in off road vehicles, not because it is not required of an off road vehicle but because the CAT get's so hot it causes forest fires up here!

[roughneck427]

I live in CA as well and I know the smog laws changed Jan 2014 with the halfway rolled out STAR program they may have just lowered the numbers to create more gross polluters to get them off the road. HC is unburned fuel and NOX is typically high cylinder temp. Air injection would lower both those numbers or as said before a new cat. CO2 reading of a dialed in afr should be at 15% post up the sheet if the O2 reading is high on ASM test a lean misfire will create high HC O2 and NOX.

[one92rs]

got the plugs changed. put in autolite 26. both places were out of the r45ts. new cap and rotor. not I do have a question.

on the egr solenoid. on the two vacuum ports. one has an orfice and the other does not. does the egr valve hook to the orfice port or open port. I had mine from the tbi to the orficed port and the open port to the egr.

and evidently I have forgotten how to log with tunerpro. guess its been a long while. need to find that tutorial again and read it.

and today I was given a 1227747 ecm out of a 1992 chevy 1500 with a 350. are the 7747 any better than the 8746 ecm's?

[one92rs]

will log tomorrow. I think I got it. had to go back in and set it to find the cable.

[EagleMark]

I'd have waited for the right plugs. Not sure about the EGR? Your 8476 is just as good as 7747 plus has an IAT.

Do you have an Air Pump?

[one92rs]

No air pump

[Fast355]

The last time my 1983 G20 had to pass emissions in DFW it was a TBI injected, vortec head 8.9:1 350 with long tubes and no cats. Running without EGR and tuned with the EBL. On the loaded emissions dyno it ran cleaner than a 2006 ULEV Honda Civic that had the then new CAN databus that would not communicate with the state machine and had to be run on the dyno.

Low Speed Test (15 mph)

HC.... Standard...332 ppm....Reading.....50 ppm
CO.....Standard....1.89%.....Reading.....0.10%
CO2....Reading 14.5%
02......Reading 0.0%
NOX...Standard...2490 ppm...Reading....72 ppm

High Speed Test (25 mph)

HC.... Standard...326 ppm....Reading.....42 ppm
CO.....Standard....2.62%.....Reading.....0.03%
CO2....Reading 14.5%
02......Reading 0.0%
NOX...Standard...2320 ppm...Reading....47 ppm

The secret.....Disconnected timing connector and massively retarded ignition timing although you could burn a .BIN that had the timing map level at 10*BTDC and accomplish the same thing. It makes the exhaust hotter and the cat function better, burning up the CO and HC and at the same time lessens the cylinder pressure and therefore NOx emissions. In all honesty it was not much dirtier running with timing advance. I just wanted to make sure it would pass easily though. When it was carbureted, I disconnected the vacuum advance hose every year prior to testing (timing was advanced nearly 10* over stock). Retarded timing + leaner air/fuel ratio = pass every time with ease. It was a little dirtier with a Q-Jet on it, but not much. One year I tried to get it tested with a box stock Edelbrock 1405 on it and it was a gross fail. The HCs were 2x the limit and C0 was through the roof. Even jetted to a 1406 it failed. I pulled the Q-Jet off the shelf, tossed it on and instant pass.

[one92rs]

Im hoping to be able to log it when i get home. Then i can post it
On here for yall to see what you can find. Actually hoping something sticks out like a sore thumb.

[EagleMark]

Maybe? That is what we want to rule out. But from what Fast is saying it's probably all the spark I have in your chip... or that and as Buzz mentioned a non efficient CAT. It's amazing how much a CAT can clean up and for the little bit of HP lost it's really just a good thing for the air!

[one92rs]

here is the log I did today. popo everywhere and 5 oclock traffic. got a good freeway run in there. and a couple small full throttles.

yeah but that chip runs very well. I like all that it does.

[Fast355]

Maybe? That is what we want to rule out. But from what Fast is saying it's probably all the spark I have in your chip... or that and as Buzz mentioned a non efficient CAT. It's amazing how much a CAT can clean up and for the little bit of HP lost it's really just a good thing for the air!

Are you using your 14.1:1 stoichiometric trick in that chip? Also have you tried lowering the 02 voltage cross points about 10%. Leaner will reduce the HC/CO but increase the NOx. Leaner than 14.7:1 can also reduce the NOx by reducing combustion temps but go too far and it will pickup random misfires that will increase HC. Retarding the timing will further cut the HC and at the same time lower the NOx. How old is the 02 sensor? If it is a non-heated sensor GM once recomended to replace them every 30K. A sensor that is starting to fail will run the engine richer and richer, causing emissions to increase.

Changing the oil seems to help as well. You could also block off the PCV vacuum hose internally as that will help lower HC.

FWIW the california .bins were always richer with the timing more retarded and almost always had an air pump. The richer mixture and retarded timing decreased NOx and the air oxidized the HC and CO.

[one92rs]

I got this chip from EAGLEMARK. that 02 sensor is less than 2 years old and is the casper electronics heated 02 sensor kit. no air pump on her either. was going to change the oil right before going back to inspection. I can block off the pcv valve. the inspector is really cool. he wouldn't even care if the pcv wasn't on there. is there a way to retard the timing manually?

[Fast355]

I got this chip from EAGLEMARK. that 02 sensor is less than 2 years old and is the casper electronics heated 02 sensor kit. no air pump on her either. was going to change the oil right before going back to inspection. I can block off the pcv valve. the inspector is really cool. he wouldn't even care if the pcv wasn't on there. is there a way to retard the timing manually?

Yea by retarding the distributor. I do not know how much timing Mark added, but it could be substantial in relation to the stock TBI tunes I have seen. If I can pass with no cat, no egr running a 454 tbi and an edelbrock non heated dual plane intake you shouldn't have an issue getting a stock tbi engine to pass.

[Fast355]

Something else that sticks out is IIRC it was well documented in the older days that the lack of factory backpressure often prevented the factory positive backpressure EGR from opening and often a TBI truck negative gbackppressure egr was needed to keep code 32 from showing up. If you have a spare set of hands get the car up to operating temp and get someone to lightly powerbrake the car and bring the engine up against the converter a little. Feel the backside of the EGR to see if the diaghram pulses rapidly.