AIR Management Valve Troubleshooting

Wite_Rabit

Hello folks! I'm working through my 1980 (California!) 'Camino. Of my projects, I'm attempting to discern whether or not my diverter valve (two-pin electrical connector, vacuum port, and three air hoses) which screws onto my Smog Pump is the source of my flaming exhaust pipe.

Heavy acceleration-> Back off the gas quickly-> BOOM POP POP POP FIRE FLAMES WHOOOSH

I believe this is why my catalytic converter found itself empty (I removed it not too long ago when I realized my muffler was my new catalytic converter...) and I want to iron out all the kinks before putting on a new exhaust and smogging my beast. I'd like to return it to a daily-driver status but I'm sure flaming exhaust won't go over well.

My other project is ironing out the kinks in my dash (no lights, some hanging wires). I'm not sure how to check my Error Codes on this model and the wiring isn't helping!

I have a feeling it's either the electrical signal to the valve or the valve itself. When I apply suction (via the mouth and a vacuum tube) to the valve it isn't holding vacuum. Should it? If not, does anyone know how to test it's electrical components?

mhamilton · Posted: Fri Oct 03, 2008 9:04 am Post subject:

Do you have the 231 V6 or the 305 V8?

It certainly sounds like the diverter is the problem (not diverting during very rich decel conditions). That, or the timing is off, but I'm sure you would notice that.

The service manual doesn't say whether the valve should hold vacuum, I believe that it has an orifice to bleed vacuum off. But, let me know the engine, because there are 2 separate AIR systems for the Buick and Chevy engines.

-Michael

Wite_Rabit · Posted: Fri Oct 03, 2008 1:34 pm Post subject:

It originally had the 305 v8 - all the original bits were kept from it when the 350 was dropped in as far as I know. Thank you for the information you've already given!

mhamilton · Posted: Fri Oct 03, 2008 6:00 pm Post subject:

Okay, there's diagnosis charts in the C4 section.

Make visual inspection of hoses and connectors for leaks and proper connections. Might not hurt to check the signal lines are routed correctly per the emissions sticker.

Check Divert Valve Operation: valve should not pump air to air cleaner hose at part throttle, but should on quick deceleration or any time vacuum signal drops below 3 in.hg. [assuming this is not okay]

Air should be diverted to air cleaner for up to 5 seconds after starting engine, then switch to exhaust ports until system goes closed loop (approx 10-60 seconds). It then diverts to air cleaner again. Air will also divert to air cleaner during open loop decelerations. [not okay]

.....this goes on for three pages, I think I'd better scan these for you! Will post back later.

mhamilton · Posted: Fri Oct 03, 2008 6:14 pm Post subject:

Here are the three diagnosis trees. The first is for the 5.0 and 5.7 L, which refers to charts A and B (for the 3.8L)

Hope this helps,
-Michael

Wite_Rabit · Posted: Tue Oct 07, 2008 1:02 pm Post subject:

I'm all tingly! I'm all too happy to run these charts as soon as possible.

One of my concerns is that my system may not be entering closed-loop mode at all. I've got to verify that my interior lights are working (check engine light, for instance, as well as choke) and try to find my diagnostic port.

It's a rat's nest under that dash.. Confused