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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: millmaster65 on February 14, 2010, 04:29:11 pm

Title: what type of EGR?
Post by: millmaster65 on February 14, 2010, 04:29:11 pm

What type of egr valve should I have on my Sub?
ported vacuum or positive backpressure or negative backpressure?
1985 K10 350 w/700r4
California emissions

Title: Re: what type of EGR?
Post by: VileZambonie on February 14, 2010, 06:10:50 pm

The ECM controls vacuum to the EGR valve electronically--through the EGR bleed solenoid.


When the engine is warm the solenoid is de-energized allowing vacuum to the EGR valve.
When the engine is cold the solenoid is energized blocking vacuum to the EGR valve.
The solenoid also decreases the amount of vacuum to the EGR valve when the torque converter clutch is engaged.

Title: Re: what type of EGR?
Post by: millmaster65 on February 14, 2010, 07:07:07 pm

besides checking the parameters you stated above for proper egr control
how would i test the valve itself? maybe 10lbs of vacuum and see if it held?
installed or removed?
intake manifold looks clear of carbon.

Title: Re: what type of EGR?
Post by: VileZambonie on February 14, 2010, 08:08:34 pm

apply vacuum directly to the egr while the engine is running. It should stall the engine.

Title: Re: what type of EGR?
Post by: millmaster65 on February 15, 2010, 02:16:19 pm

Thanks a bunch!