bakerstreet

I have a 92 RS 305 TBI automatic with 149,000 miles, all stock & the engine seems to be running rich. The exhaust smells bad & when datalogging the BLM & INT always go down to 108 after it goes closed loop.

The car doesn't smoke at all & the car runs absolutey perfect, except that i can't pass emissions b/c of this rich issue.

All sensors tested good & they all work as normal when datalogging. Even though all sensors tested good, because of age i replaces all sensors (map, cts, iat, knock, new acdelco o2 sensor), new fuel pump & fuel filter, air filter, spark plugs & wires, cap & rotor, ignition coil, the throttlebody was rebuilt & the injectors were cleaned & are the correct ones for my engine. The intake was removed & cleaned & the egr works good as well.

All spark plugs are firing & the engine doesn't miss at all.
The fuel pressure is @ 11 psi & was also 11 psi with the old fuel pump as well. The engine vacuum at idle is about 21".

Ive owned the car for several years, & the exhaust has always smelled bad, but i used to live in a county that didn't have emissions testing, but now i live in an emissions county.

I took a video of the injectors spraying & the cone shape seems perfect, & while watching the video you can see the injectors pulsing on & off.

I check for fault codes often (& there are none) & it only flashes code 12.

The only thing that i can think of is that the ecm 1228746 may not be functioning correctly.

Any ideas?

ex-x-fire

Before replacing the ecm make sure the grounds are good, these can be at the back of the heads or t stat area. Make sure the ecm is getting the proper 12v & 5v signals too.
Make sure the map sensor is hooked to the proper connection or hook it to manifold vacuum (anywhere below the throttle plates).
Check the timing & make sure it advances when you rev it.
Do a resistence check on the cts. The resistence changes w/ temp, so you'll need to find the ohms/temp values on the web.

Scorp1us

I'd think your IAC port was clogged.