My code scanner is coming back with codes for insufficient EGR flow and inoperative thermactor on both banks. I probably need a new EGR valve, but what about the air pump? Or could it be check valves? Any advice or info would be greatly appreciated.
Check the wiring to the solenoids (for the smog pump). There should be key-on power and one wire which is grounded when the computer tells it to (activating the solenoid and valve).
If you put a test light on each solenoid's wiring and have the car run codes, your test light will illuminate when the computer cycles each solenoid. This tells you the wiring to the solenoid is intact.
Ensure there's solid manifold vac to each solenoid and that when each is energized, manifold vac reaches the particular valve (TAB or TAD, aka AIR1 and 2). You should find the issue by this point.
The computer has no idea if your smog pump is even in the car, so don't sweat that part.
With the EGR, take it off and clean it. Spray the exhaust fitting's nut with PB before you begin. Then hit it again upon trying to remove it. Then just remove the two bolts holding the EGR valve and you should be able to remove it. I use a bore brush and carb cleaner in the passage. Just be cognizant of the diaphram - no solvent or brush near it.
Ensure the EGR position sensor is functional. Sometimes the EGR seats wear and it spits a code because the sensor is out of calibration. If this is an issue, post that it is and I might have a free way to fix it.
Also ensure the EGR is getting vacuum. It works like the Smog in that there's a solenoid which regulates vacuum. The solenoid is also under the passenger fender. There should be manifold vac to the solenoid and vac to the EGR (in varying degrees) at steady state cruising. All you can really do is make sure there's vac to the solenoid and that the line from the solenoid to the EGR valve isnt leaking.
Thanks! Now I have something to work with and I'll do a little more poking around. I did notice that only the 332 code for the EGR was displayed during the KOEO (key on engine off) test. Codes 314 & 311 showed up during the KOER (key on engine running) test. A while back (a couple years ago) I got a code for the EGR valve. I think it was the same one (332 = insufficient flow) and I remember trying to connect a vacuum gauge to the solenoid and getting no reading. I took a look in the shop manual and from what I recall the vacuum at the solenoid is very slight. I tried replacing the EGR position sensor first, but still got the same code and then I replaced the EGR valve. Its not really that old. There's probably less than 50,000 miles on it. Anyhow, I appreciate the advice and I'll check some more things out under the hood before I go replacing any parts.
Well my first test was applying vacuum to the EGR which resulted in a lower idle speed so I'm assuming that the EGR valve itself is okay. It might be my source vacuum that's causing the trouble. As soon as the rain lets up here in NJ I'm going to do a few more tests. I'll try applying vacuum to the bypass and diverter valves and also I'll throw a vacuum gauge on to see if the EVR is pulling any vacuum at part throttle. After that I'll check the electrics to the solenoids. Also, I'm gonna pull the hose off the smog pump to see if its actually blowing any air out.
Okay, here's what I've discovered so far. I've got no vacuum at all getting to the EGR valve, but if I apply vacuum manually the idle RPM drops. I've got slight vacuum at the TAB & TAD valves, maybe 1-to-2 inches max depending on engine RPM. If I manually apply vacuum to the bypass valve I can feel the change from air being vented to the atmosphere and not venting at all. With all the vacuum lines attached the bypass seems to constantly vent to the atmosphere no matter what RPM the engine is revving at, but it really blasts the air out at higher revs so the smog pump must still be working okay. If I manually apply vacuum to the diverter and hold my hand on it I can't feel a thing. I don't know if its working or not. I guess I'll have to pop the big hose off and see if the valve works or not. There are some plastic vacuum tubes inside sort of a harness for lack of a better word. It looks like the red tube is the source (I know my manifold vacuum is good) and the green comes back from the EVR (I'm assuming) to the EGR. The beige goes to the bypass and white to the diverter. I'm not sure of the easiest way to gain access to the solenoids. It looks like that stuff is buried in the fenderwell.
I did some more tests with the vacuum gauge only this time with the code scanner connected so I could check vacuum in KOER mode. I still got nothing at the EGR valve. At the TAD valve I got about 2 inches, then 5 inches and then nothing all with abrupt transitions so the solenoid must be working somewhat I would gather. At the TAB valve I still only got about an inch or two of vacuum and then nothing again with an abrupt transition. I decided just for $h*t$ & grins to split the vacuum junction block (my own nomenclature) and I ran a separate vacuum line from a spare nipple on my elbow adapter (its normally capped off) down to the "junction block" where the red plastic tube would normally be connected. I capped the beige or pink colored line and hooked the vacuum gauge up to the green line. Lo & behold during the KOER test I got about 5 inches of vacuum at one point before the scanner started flashing codes. After this I swapped the green and pink (or beige, whatever it is) lines around so now I had the vacuum gauge on the pink line and the green was capped off. I ran the KEOR test and the gauge showed 13 inches of vacuum for a little while then it dropped abruptly to zero. The solenoid seemed to have some functionality. I then connected the "junction block" back together and double-checked the pink (beige) line and I was back to about 1 - 2 inches of vacuum. I removed the pink line altogether and blew into one end while covering the other end. It doesn't appear to be split or cracked so somehow I must be losing vacuum at the "junction block".
Well, I checked for vacuum at the EGR valve a few different ways. I tried the KOER method and got nothing. I tried without the code scanner and just operated the throttle manually and got nothing. The only time I got a reading (5 inches) was when I split the union of red, green & pink plastic tubes and supplied a separate source vacuum to the lower red tube. I also got better readings from the other lines when I did this. Most surprisingly was the pink (or beige, whatever) line which showed 13 inches during KOER. My source vacuum is about 17 inches, but what should I be reading at the TAB/TAD and EGR valves? My manual method (sucking on a hose!) generates about 5 inches which seems to be enough to actuate the valves.
sounds like you could just redo the vacuum hoses with rubber vacuum hose. sounds like the original hoses have gone bad. i've replaced the plastic with rubber hoses on many different cars and never had a problem.
it's not hard to do, just make sure you have enough tees and correct size vacuum hose