Vacuum Line Nightmare - 09/17/2011

Since the car didn't pass smog due to failing the EVAP test and running too rich, it's time to investigate the vacuum line situation and the fuel tank vent line situation.

Here we have the patient.

Jacking up the car in the dirt is fun!

The other side is raised. The differential tag is still present, but not easily read. There was no code in the usual places, so I still don't know the differential code.

Here's our culprit. Right between the frame rails below the passenger door. Need to replace this one!

The other vent from the tank itself. Might as well hit this while I'm here too.

And it's replaced! It was still well-fitted, but it was cracked and dry. All of the fuel lines have been replaced semi-recently as they are still soft and pliable.

Fixed the offending line.

Now onto the engine compartment. First off... this is a distributor retard orifice, not an EGR part...

The vacuum line routing is mostly correct, but not completely.

Side view, EGR valve & back pressure transducer next to choke. Need to verify their functionality.

Linkages and mechanisms all hooked up.

Don't get me started on the teflon tape used to seal 2 pressure fittings...

Carb is removed! Metal shield between intake and gasket still in place.

The carb off of the engine!

Airhorn removed. Nice and clean inside.

Removed carb parts. Primary rods are 45L, secondaries are DB. Someone tweaked the power piston arms and they were angled funny... Luckily the choke pull-offs all work.

Gooey. Looks like someone decided to plug up potentially leaky plugs...

Power piston arms are all straightened out after a little love tweaking...

Carb is all back together and adjusted.

Carb back on the engine! Teflon was removed despite the appearance of it still being there.

I rebuilt the vacuum harness to the distributor. It was dry-rotted and cracked.

Dig the 5 blade flex fan! Moves quite a bit of air...

Engine put back together and gets 20in of vacuum at idle! Wow!

All put back together with all vacuum lines replaced.

More complete! No wingnut on the air cleaner is a bummer.

Engine back together!

Good news and bad news resulted. The good news is I found my tank vent leaks! And replaced all of the vent lines from the carb to the back of the tank. So that problem should be fixed! And the EGR valve works properly. The bad news is that the back pressure transducer that is in-line with the EGR valve is failed. It doesn't hold vacuum, so the EGR doesn't operate anymore. This isn't a problem for visual, but without EGR I might not pass smog on the dyno even with a better running carb than before. GM discontinued the part and NO ONE sells it, so this could be a potential problem. Also, the vacuum advance in the distributor doesn't operate, so I'll have to fix that one of these days too.

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Last updated September 17th, 2011