PCV and Catch Can

[Mez]

This last weekend, we had a 3 vehicles with idle issues that were traced to incorrect catch can installation or missing PCV valves. These cars had aftermarket intake manifolds, throttle bodies, and air filter assemblies so someone else made the mistakes which we caught.

The LS1, LS6, and LS2/LS3 all have different PCV systems. If they are modified such as removing the PCV valve, capped vent lines, it can mess up the idle air flow or cause excessive oil consumption by pushing oil to enter the intake manifold.

Just a heads up to everyone that tunes on a regular basis, check the PCV and related vent lines to make sure they are hooked up and are working properly.

Here is a good explanation of the various PCV systems.

PCV SYSTEMS

[logikal6785]

When you say incorrect, do you mean that the line positions were swapped on the can, or ... ? Just curious what you ran into.

[Mez]

When you say incorrect, do you mean that the line positions were swapped on the can, or ... ? Just curious what you ran into.

Miss PCV valve, hoses connected to the incorrect port on the valve cover or valley cover, catch cans connected to the wrong lines, and plugged lines.

Owners or shops will remove the PCV valve then reconnect the hose or replace it with an aftermarket filter. All this does make it an uncontrolled vacuum leak.

Conclusion: Have the correct PCV schematic handy and check it on every car that comes in the shop especially if the owner is complaining about poor idle.

[08RED2500HD]

Good info

[HoP]

Owners or shops will remove the PCV valve then reconnect the hose or replace it with an aftermarket filter. All this does make it an uncontrolled vacuum leak.

Seen this so many times. Leave the dam PCV Valve, all your doing is adding the catch can between the valve and manifold.

[cbloveday]

Seen this so many times. Leave the dam PCV Valve, all your doing is adding the catch can between the valve and manifold.

X2