Replace belt driven smog pump with electric?
Thread Starter
Instructor
Joined: Jul 2004
Posts: 137
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From: CT
Replace belt driven smog pump with electric?
Has anyone done this successfully, and if so, any tips?
My '86 failed emissions and I found a leaky FPR diaphragm. Installed a Holley AFPR and all is good, except the AIR switching valve apparently sucked some fuel through the vacuum line (Tee'd with the FPR) and won't hold a vacuum... It still seems to have the muscle to switch to the downstream AIR diverter valve but the vacuum leak bothers me, and plugging it seemed to give me a better idle. I bypassed the valve to get AIR flow to get through emissions but lost the AIR cutout when accelerating, etc. The valve is discontinued, and was $200 when available. I tried mail order used ($100 for the pair) and the upstream valve still tested bad (bad vacuum, but still switched the AIR) while the downstream tested good. I asked them to have a replacement tested before shipping, and it tested better than the others, but still bleeds down within a second. I suppose this is a common failure mode with this valve.
So I'm thinking about installing an electric smog pump like on my '95 F-body... but my smog pump is new-ish and I might give one more try to find a good diverter valve. Also, do later C4's with belt driven pumps use different switching valves that can be fitted to the 85-86?
My '86 failed emissions and I found a leaky FPR diaphragm. Installed a Holley AFPR and all is good, except the AIR switching valve apparently sucked some fuel through the vacuum line (Tee'd with the FPR) and won't hold a vacuum... It still seems to have the muscle to switch to the downstream AIR diverter valve but the vacuum leak bothers me, and plugging it seemed to give me a better idle. I bypassed the valve to get AIR flow to get through emissions but lost the AIR cutout when accelerating, etc. The valve is discontinued, and was $200 when available. I tried mail order used ($100 for the pair) and the upstream valve still tested bad (bad vacuum, but still switched the AIR) while the downstream tested good. I asked them to have a replacement tested before shipping, and it tested better than the others, but still bleeds down within a second. I suppose this is a common failure mode with this valve.
So I'm thinking about installing an electric smog pump like on my '95 F-body... but my smog pump is new-ish and I might give one more try to find a good diverter valve. Also, do later C4's with belt driven pumps use different switching valves that can be fitted to the 85-86?
Team Owner
Joined: Jan 2003
Posts: 20,306
Likes: 242
From: Summerland B.C. Canada
Can't offer any advice, but when I deleted my AIR stuff, I gave away the diverter valves for nothing. Maybe a post in the parts section will yield you a free or cheap valve. I know there are lots of AIR free rides out there.
Although you can pass the sniffer without a smog pump entirely.
