Before you dump money into this,take the car to Chris at VIP auto repair.he knows these cars inside and out.He is on Soledad,across the street from home Depot.(Ruther street i think).My02.He is a GM demi God.Hope this helps.

 

Cell 16. I'll check again later today. I'm going to add an extra ground between the engine & the body, I get about .5 volts while cranking.
Thanks,
Walter

 

Cell 16 is only for idle. Aren't they testing the engine under load, at two different RPM? You have to get the LTFT's for EVERY cell, not just the idle cell.

 

Took the car to a shop that can also check the tailpipe emissions. They did a top engine clean out 3 times & then had to replace the O2 sensors again. The car finally passed.
Thanks for everybody's help,
Walter

 

Here I am again. The car barely passed last time so considering that I had over 300,000 miles on the engine I replaced it with a low mileage used engine. The car failed again this year.
Latest test:
Co2. O2. Hc. Co. Nox

15mph 14.5. .3. 45. .04. 646
25mph 14.5. .2. 38. .04. 626

Car runs great, gas milage is good. Lamda is 1.012- normal. Idles good. Smoke tested for vacuum leaks. No vacuum leaks. All vacuum hoses new. O2 sensors new. No exhaust leaks. Fuel trim is normal. Fuel pressure normal. New delco pump & regulator. Egr valve & solenoid new. Optispark new. Cat is new. Replaced again with higher load cat. Tried forcing egr valve open, no help with nox. Egr flow is good. Egr system tested ok. I have the car at a Star smog station and they are running out of ideas. I am going to replace the injectors next. I also guess I need to do a carbon clean out. Does anyone have any other suggestions? The smog guy said the nox goes down if he forces the car a bit richer I have had this car for 10 years and never even had an issue with smog! Please help.

 

Hey did you get your car to pass smog?

 

You might want to try an e-mail (left click on his screen name). He has not visited this site since 12/15/13

 

After much stress, anxiety and money I discovered Magnaflow cats don't work for our cars. I installed a walker cat and the nox numbers magically became normal. If you search my name you will find my final resolution. Good luck.

 

glad you got it worked out....but FWIW I replaced my stock 100k CATS with the MagniFlo OBD2 CARB ones (fing not cheap) years ago and have passed Calif. smog every time....with a 383 H/C motor

for OBD1 cars...any replacement CAT should work

 

"For OBD1 cars...any replacement CAT should work"
They should, but the Magnaflow Cats definitely don't work in our cars.

 

Was the cat you installed possibly an ebay "universal" cat with an AIR connection pipe between the beds that you left capped?

 

I had all 4 cat supplied & installed by a reputable exhaust shop. All the cats were California legal. I am service manager at ajaguar shop and have been dealing with them for 10 years.

 

If I read this correctly over the course of 3 years you bought 4 different Magnaflow CARB certified catalytic converters, and they would not allow the vehicle to pass the CA emissions test. Didn't you think it worthwhile to confront Magnaflow on this problem?

Something isn't adding up here.

 

Tech support at Magna flow recommended trying another brand cat. I wonder if the Magnaflow cat has too little back pressure to work with our egr system. The magnaflow cats were all 3" and the only carb cat by walker was 2.25". Much closer to the OE cat.

 

wba

you live in SoCal, me to. What I found is since this "STAR" fing smog test deal happened muffler shops will not install any CAT on a OBD2 car (yours is OBD1 so you may be OK) that is a different size than what came stock on the car.

My car came with 2 1/4" CATS but I bought 2 1/2" CATS (my car is a B-Body) back before this STAR deal happened. 2 1/2" is what the Vette LT1's have

Odd Magniflo said to try another brand. But for me their CAT works fine and has passed smog since installing them

For your OBD1 car I would think any CAT approved for Calif would work. Walker, Catco, etc