Desmogging 280Z Attack Plan - Engine & Drivetrain - Classic Z Car Club Skip to content

Desmogging 280Z Attack Plan

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According the my Haynes manual, these are the smog things on the L28 (auto trans) and I would probablly do these things with them:

BCDD-- disconnect vac line/adjust

EGR Control Valve-- Remove, cover hole

Thermal Vacuum Valve-- remove, plug

Backpressure transducer valve-- remove, plug holes

Vacuum Delay Valve-- remove, plug holes

Altitude Switch-- remove & bypass

Vacuum Switching Valve-- disconnect from dizzy

Dashpot-- ?

any suggestions?

thx

Why?

They do nothing to hinder performance and or operation of the vehicle.

Hell I had a annoying problem on my ZXT that a simple reinstallation of a pcv fixed, it was removed by the PO.

I'd have to agree with ZmeFly. Each one of the things you mention have a negative effect on the cars performance when non-functional. Some more than others. So, if you remove them all, what do you intend to do to compensate? The troubleshooting charts would be useless since many performance problems can be traced to malfunctions of these devices.

  • Author

The idea was to clean up the engine. All that's left would be the intake, headers, dizzy, and injectors/ injector rail.

At the least I would like to remove the EGR valve.

I suppose I could do one at a time, and see if it's good or bad, then replace it .

Well, it runs and I got more important fixes like the headlights. That's why I do the reasearch & keep notes,

thx

  • 1 year later...

If you plan on removing the egr valve, you'll also have to plug the hole in the exhaust manifold.

Also, I've been trying to figure out how to clean up my engine too, so here's one thing I found out: The breather hose from the valve cover runs to the boot after the mass air sensor (at least in CA). There's a vacuum in that line sucking into the boot, away from the valve cover. You'll need to put some sort of catch or tube or filter on the end of the valve cover to allow it to breath, but if you plug the hole in the boot, you should be good. That's step one in theory, and pretty simple to replace if you have to go back.

S
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good one ,dip.while he's at it he could cut a brake line or two...

by the way thanks for the info this morning. it was "super".

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