# Vacuum hose diagram - '86 C20 - 350cid



## raceman6135 (Jun 14, 2001)

I've been searching for a vacuum hose routing diagram for my 1986 C20 with a 350 "M" engine for quite a while.

LMC Truck has some decals, but not the proper one for my year and emissions package. I've tried searching this site, other sites (http://www.classicpickups.com, for example), Google, Yahoo!, and Altavista even, all to no avail!

My original air cleaner decal is 1/2 ripped off, and of course, the 1/2 that is gone is the 1/2 that had the decal's part number on it, so my dealer has been less than helpful.

My local library and parts stores don't seem to carry the Motor's Manual with all of the emission, vacuum and wiring diagrams in them, but they'd be happy to order one for me for $150 plus shipping (should arrive in 6 - 8 weeks).

I've even hunted around the wrecking yards, peeking over the fenders to find a similar air cleaner that I would have bought just to get the decal! Still turned up empty-handed.

Any leads would be greatly appreciated!

Oh, the truck is a Canadian built 1986 C20 crew cab with the 350 "M" engine. It came with the A.I.R. pump but not an E.G.R. It's carbureted and has a "normal" HEI -- there's no electronic feedback on the carburetor, and it's the old style "coil-in-cap" style of HEI with the 4-pin module.

DJS


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## Chuck Smith (Dec 30, 1999)

Keep an eye on ebay. You can get a 1986 GM Light Duty Truck Factory Service Manual (10, 20 & 30 series trucks) that will have the diagram and everything else you could ever want to know about your truck. Forget Motor, Chiltons, et al.

Unless you need the decal for restoration purposes....

Why do you need it if you don't mind me asking?

~Chuck


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## raceman6135 (Jun 14, 2001)

Thanks for the tip about ebay, Chuck. I should have mentioned that I check it once in a while, but jeez, how often do you have to check? (How can you tell I'm fairly new to ebay!!)

The American ebay site is huge, and their search engine seems to rely heavily on only the sellers description, so when words are spelled incorrectly or the description is less than accurate, you get some pretty wonky returns.

I'm hoping to find a vacuum diagram (or a decal, either will accomplish my goal) because this truck seems to be a split-personality of sorts.

The intake casting number seems to match with the build date and the VIN/block stamping numbers, but it doesn't have a provision for an EGR. There was an air pump on the engine, but the previous owner had removed pieces of it, plugging and cutting hoses "willy nilly."

Likewise with the ported vacuum switch that's screwed into the thermostat housing (a four port unit). Not to mention the solenoid that kicks the throttle open upon deceleration (can't remember the exact name of it) and its associated wires and hoses.

Some indicators point toward a US Federal emissions package, others toward a Canadian setup, but the carburetor number corresponds to a California unit!

I could just toss everything away, but I'm planning on selling this truck, and in this market (Calgary, AB), there are lots of trucks for sale (farming, ranching and oil field country, don't you know), and hacked-up trucks are quickly passed over except by those willing to part with only $100 to obtain them. To say the market is tough would be an understatement!

Maybe I should just trash it all, slap headers and a 2101 on it and roll the dice 

DJS


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## raceman6135 (Jun 14, 2001)

Holy [email protected], who's that long-winded guy who always types in red?


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