bakerstreet

I have a 92 rs 305 tbi automatic with 145,000 miles on it, & it keeps failing hc, co & nox during emissions testing. I've owned the car for over 15 years & the car runs great & has always run great. The exhaust has always smelled bad, but it doesn't smoke nor does it burn any oil. Inside the tail pipe is black & sooty, but it has never smoked at all. I now live in an emissions county & now i'm having to deal with emissions.

It's all tuned properly, new distributor, fuel pump, cts, map, plugs, wires, o2 sensor & timing is @ zero degrees as per specs. Fuel pressure is at a steady 12 psi, the tbi sprays perfectly shaped cones w/o any dripping. The egr funtions as intended, it doesn't leak any fluids & the cooling system is in great shape as well.

I replaced the spark plugs & o2 sensor & they looked normal, without any soot or any indication that the car was running rich or lean.

I replaced all of the above parts (even though they were all within specs).

No exhaust leaks, cat is about 9 years old, there are no codes, & except for the exhaust smell, this car runs perfectly.


I've been datalogging, & my closed loop results are:

IAC-29

Coolant temp-205 degrees f

Speed-0 (just idling)

Map-1.1v (31.8 KPA)

RPM-750

TPS-0.49v (-1.2%)

Integrator-127

O2-constantly switching between .1 & .9mv

Batt-12.8v

Knock counter-2

BLM-108

IAT-110 degrees f

Everything is within specs except for the BLM's, & according to the datalogs it doesn't matter if the engine temperature is 180 degrees or 235 degrees, the blm always goes to 108 after the engine has warmed. The integrator mostly stays @ 128 but ocassionally goes up to 133 but then quickly back to 127-128.

Can u guys think of any other issues that may be causing this problem?

bakerstreet

Anyone have any ideas?

Seafarer12

I am leaning towards a bad cat. How many miles do you have on it? The aftermarket cats don't last nearly as long as the factory ones.

iggy1991

Put some dry gas in the tank then try again. Dunno if they carry guaranteed to pass in a auto parts store near u. That could help.

WilliamSilver

iTrader: (6)

BLM of 108 shows a rich condition, and high HC would support that. I would figure out why your BLM is at 108.

Is it at 108 at idle as well?