How do I test the EGR control valve after removal?

Remove the E.G.R. control valve and apply the specified vacuum of −13.3 to 14.7 kPa (−100 to 110 mmHg, −3.94 to 4.33 inHg), then visually inspect the valve for signs of damage, wrinkle or other deformation.

How can I check EGR operation with the engine running?

With the engine at idle, push up the E.G.R. control valve diaphragm by manually pressing the bottom dish. It is normal if the engine loses stability.

What engine speed is used to check the thermal vacuum valve and carburetor vacuum?

Disconnect the vacuum hose from the E.G.R. control valve and increase engine speed from idling to 3,000 to 3,500 rpm, confirming the thermal vacuum valve is open and carburetor vacuum is present.

How should the EGR control valve seat be cleaned?

Clean the E.G.R. control valve seat with a brush and compressed air, and always use a new gasket when reinstalling.

What indicates the EGR control system is normal?

The E.G.R. control system is normal if the diaphragm moves upward; if not, check the system as in step 3.

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Nissan EGR Control Valve Inspection & Vacuum Test - EF & EC-26 Service Manual

E.G.R. control valve inspection with applied-vacuum spec, Nissan EF & EC manual

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EGR control valve inspection: apply 13.3-14.7 kPa (100-110 mmHg, 3.94-4.33 inHg) vacuum and confirm valve operation; engine should lose stability when diaphragm is pushed up.

AI caption June 2005 · Photo 126 of 412

This is page EF & EC-26 from a factory service manual section titled "Exhaust Emission Control — E.G.R. System, Inspection (Cont'd)." It continues an on-vehicle inspection procedure for the EGR system: the system is normal if the EGR valve diaphragm moves upward; otherwise the reader is directed to step 3, which involves disconnecting the vacuum hose from the EGR control valve, raising engine speed from idle to 3,000–3,500 rpm, and confirming that the thermal vacuum valve is open and carburetor vacuum is present. Step 4 instructs pushing up the EGR control valve diaphragm by hand at idle; the engine losing stability indicates normal operation. The right column covers bench testing of the removed EGR control valve: apply a specified vacuum of −13.3 to 14.7 kPa (−100 to 110 mmHg, −3.94 to 4.33 inHg) with a hand vacuum pump, visually inspect the valve for damage, wrinkling or deformation, and clean the valve seat with a brush and compressed air. A bold note reminds the reader to always use a new gasket. Illustrations (figure codes SEC142A, SEC143A, and two partially cropped SEC1- codes) show the thermal vacuum valve location, manual diaphragm testing, vacuum pump application, and valve seat cleaning.

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Frequently asked questions

How do I test the EGR control valve after removal?: Remove the E.G.R. control valve and apply the specified vacuum of −13.3 to 14.7 kPa (−100 to 110 mmHg, −3.94 to 4.33 inHg), then visually inspect the valve for signs of damage, wrinkle or other deformation.
How can I check EGR operation with the engine running?: With the engine at idle, push up the E.G.R. control valve diaphragm by manually pressing the bottom dish. It is normal if the engine loses stability.
What engine speed is used to check the thermal vacuum valve and carburetor vacuum?: Disconnect the vacuum hose from the E.G.R. control valve and increase engine speed from idling to 3,000 to 3,500 rpm, confirming the thermal vacuum valve is open and carburetor vacuum is present.
How should the EGR control valve seat be cleaned?: Clean the E.G.R. control valve seat with a brush and compressed air, and always use a new gasket when reinstalling.
What indicates the EGR control system is normal?: The E.G.R. control system is normal if the diaphragm moves upward; if not, check the system as in step 3.