How To Fix A Failed EGR Solenoid

The control solenoid for the Exhaust Gas Recirculator (EGR) on older carbureted GM V8s appears to not be available as of this writing (January 2012).

Here is an alternative I devised for the 350 cubic inch Corvette engine I put into my 1985 ElCamino. Since the 350 is using the same pollution controls as the original 305 cubic inch engine, I have no reason to think the alternative EGR control solenoid would not work for a 305 too.

One caveat is in order: I have no idea if this modification would upset the California pollution authorities. I gather they generally take a dim view of any modifications in the emissions control system.

Here's a picture of the original bracket with the original Manifold Absolute Pressure sensor (MAP) above the EGR control solenoid:

In my case the EGR control solenoid was leaking vacuum above 17" Hg. Even with my relatively mild cam I should have seen around 20" Hg.

In a nutshell, the alternative is to use an EVO-3 industrial solenoid made by Clippard.

The Clippard EVO-3 solenoid valve is good for 25" Hg which should be more than adequate for this application. I also ordered 1/8" hose barb to 10-23 fittings in the "L" configuration (part CTO-4) and straight configuration (CT-4). The bill with ground shipping and US$10 handling was under US$50.

The fabrication is pretty simple and can be done with an electric drill and hand tools:

I had to fashion a comparatively simple "L" bracket. I used some scrap aluminum angle stock.
A wad of open cell foam wrapped over a hose barb and attached with a bit of contact cement or automotive weatherstripping cement provides a filter for the EGR valve vent. The solenoid has a 0.025" orifice so it's a good idea to have something there to keep from sucking in dirt when the solenoid vents the EGR valve. A friend suggested a ceramic bubbler for a fish tank — I think it's a good idea and will probably replace the foam.
I also spliced the leads onto 16ga. automotive wire. Shrink tubing protects the soldered running splice and is about the right diameter to let a 1/8" nylon "P" clip serve as a substantial strain relief.

The original solenoid measured about 28 ohms — it consumed nearly a half ampere! The new solenoid sips power with a 260 ohm coil. There is no reason to expect the lower power requirements will confound the Electronic Control Module (ECM).

The details should be evident from the pictures below. Click on the picture to get a high resolution image. Use your browser's "Back" feature to get back to this page.