Diverter valve...

[Mister5150]

I'm quite sure my smog diverter valve has bit the dust, on cars I've owned in the past I have just removed the entire air system however although this is not my daily car I still need it to pass emissions, sooo.... what is everyone else doing as far is this goes, can I fix it? Buy new? Or re route it? Or just remove and make it look nice, looking for ideas, haven't been in the garage to tinker as its been nuthing but snow in the CO..

 

[mikemcvaney]

Put a modern cat on it then you wont need the air system

 

[b4black]

x2. The newer convertors do not use an air tube. That's what I did in Illinois when they were still testing pre-'96 cars.

If you need it for visual inspection, I'm sure someone here has one to spare.

 

[Mister5150]

Thanks guys, I was convinced that it was not diverting to the cat and just continued to pump to the manifold, so to test my theory I routed my smog pump to the cat and blocked of the intake hose, removing the diverter valve. My theory was correct, running better now however I think I have some compounding issues, everything under the hood has been replaced at this point except the carb,so either I have a weird vac leak or my carb is done. Symptoms are intermittent so it's hard to put a finger on it, exhaust after fire sometimes, idles at 1000-1200 in park then drops to 400-500 in gear if it doesn't cut off, however when you give it gas look out...

 

[b4black]

Is this an '83 running off an ECM?

When the AIR is pumping into the manifold, this is the exhuast before the O2 sensor, which will throw the sensor off. It only pumps here before going into closed loop.

Have you ever connected a scan tool to it to see what all the sensors are seeing?

 

[Mister5150]

Yes it is an 83 running the ECM, i know I have a vss issue somewhere and I need to try and locate a scan tool

 

[Mister5150]

Just trying to find vac leaks I decided to unplug the egr valve vac line and bam! Everything started workin no idle miss, held idle steady at 650-700 rpm in gear, didn't bog or die, and no after fire when I killed the engine, it does idle kind of high in park around 1-1200rpm with a slight surge from 1000-1200 rpm, if I can get that sorted I may have a close to perfect running c/t. Sooooooo any suggestions for the egr?

 

[b4black]

Good find! People often overlook the devices and concentrate on hoses when looking for vacuum leaks.

I had a bad EGR valve and replaced it with an aftermarket universal fit unit by Tomco that used different size openings (looked like a washers with differing inner holes sizes). Lifetime gaurentee - lasted only a year and so did the second.

I believe the specific GM part number for the '83 TR is discontinued. I had a new AC Delco EGR from a different motor (3.8 2-bbl?) and used that. Works well. I would not recommend running long without it. With it disconnected, it would get knock while crusing down the highway. While you have it off, make sure the passage in the plenum is not full of carbon "rocks".

 

[Mister5150]

Thanks Rich, I will pull it off and try to match it up to something, I'll start with the 3.8 2bbl