FULLSLP1

89 iroc 5.7 350 in california

before the 1st time i changed plugs ,wires,cap,rotor,maf,o2,fuel injectors.....

and failed by 9 points (hc).....

before the second time i changed plugs again, switched from 160 thermostat to 195, changed oil, unplugged one electric fan, and ran a full tank of "guaranteed to pass smog " that should have helped slip through the 9 point gap....nope did nothing i posted the exact same numbers except for (nox) went down and (co) when up very slightly.......this car runs so good, idle,full power,no smoke, gets great mpg....so what do you guys think???

the cat converter is only 4 years old... do you think i fried it running rich with the bad injectors..?? thanks for any help

NovaTodd

Replace the cat. I killed a cat and both O2 sensors with a blown head gasket. I paid $100 installed for a 3". Running rich will make the cat run really hot and melt.

stanghunter211

Make sure the vac line to your egr valve is hooked up. I failed a few months back and could not believe it. I tore the car inside out looking for possible clues, and I just happened to peer under the plenum and saw this vacuum line just dangling. It was the line to egr, without it hooked up, I failed miserably. I connected the line and smogged the next day, and it was a night and day difference. Best of luck man

Will

transxtreme

My new truck is running rich as hell, Im pointing my finger at the FPR, anybody else got a suggestion, 350 TBI...sorry, not trying to jack ur thread.

FULLSLP1

thanks guys... usually when the egr or hoses go bad your (nox) goes through the roof... (high cylinder temps) but mine was way low (egr)heck it's only 2 years old... as for the tbi truck...check your fuel press but running rich is either no spark, weak spark, bad o2 sensor telling the ecm to dump gas in or a leaking fuel injector .. that was mine...

UP_Z28

Alot of times it can be as easy as advancing the timing some then putting it back when your done , I have honestly seen that work on more than one occasion , good luck.

Kevin91Z

You cant advance the timing more than 3 degrees, as they do check the timing to make sure its stock. Stock for a TPI engine is 6 degrees.

What part of CA are you in?

FULLSLP1

im in oceanside....

and like i said i failed the second time with the exact same (H0) as the first time...the only thing i don't know is if i should pay out the nose for a test and repair shop or just replace the cat .. it's three inch exhaust so i can get a cat for $100 and have it installed for $50 // or pay $75 at testnripoff for the diagnostic then $150 for the cat then they charge $125 to install plus an all new smog check $65.....at my smog station it's $25 since i failed twice already...what do you guys think!!??

$175 take a chance

$415 play it safe

NovaTodd

I just went to a small shop that had the 3" cat in stock. It cost me $100 installed. He had it done in 20 minutes.

90rocz

Did you set the TPS to .54v @ idle, and over 4.20v @ WOT?
Weak spark, coil?
Use some Berryman's B12 Chemtool, help clean the injectors and helps the CO when it's burned.
Make sure fuel pressure isn't low. the spay pattern will be $h!t and it won't all burn.
And if you can, try a different E-check station, I've had some that had high failure rates around here, and simply drove to another and passed!..

Just some ideas..

FULLSLP1

fuel press is perfect (new fuel pump) the injectors are new that was my initial problem and it has a full msd system ,coil box,wires and checked the TPS its fine . any of those would cause some drivability problems .this car pulled a 14.15 @ 100.2mph with msd ,k&n, and some trackbite so its making full power....p.s. its a 2.77 car

IROC-T

If it's not an AC o2 sensor,change it also.

90rocz

I run a Bosch Platnum 02 with good results.
I had trouble with one passing and ran 3 bottles of Isopropynol Alcohol Gas Dryer in it and it passed.
There's also lot's of "E-check Pass" additives out there, guarenteed to pass or your money back, my cousin used one the day before an E-check and it ran a whole lot of black qrap out of the tail pipe, cleared, and the next day passed!..

FULLSLP1

yes its a ac delco o2 sensor and i ran "guarantee to pass smog" crap and it did not bring down my "HO" by not even ONE point...

90rocz

HC or Hydro-Carbon is usually high b/c your burning oil. Bad valve seals, bad PCV valve, blow-by, old oil, thin grade oil, cheap oil, thinned oil (by fuel or other contaminant)can cause high HC levels.
Try some "Engine Restore" to help ring & valve sealing, use a thicker(10w40 or higher) oil, spray some carb cleaner in the PCV valve to free it. (but a buzzing PCV is bad also, the spring gets weak and it buzzs.

Just some more ideas, I know they're more strict there, so even invisible amounts of blow-by might fail...