FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.

Without Back Pressure Transducer


Single Response Tests
1. Check all system vacuum lines for proper routing and secure connections.
2. Inspect vacuum lines for wear or damage and replace as necessary.
3. Ensure there is no vacuum to valve at idle. Recheck hose routing if vacuum is present.
4. Make sure there is vacuum at valve at kickdown RPM with engine at operating temperature. If there is no vacuum, trace system vacuum lines back from EGR valve and replace components as necessary.
NOTE: Refer to vehicle emission decal for kickdown RPM specifications.

Diaphragm Test
1. Cycle valve through full travel, using finger pressure on diaphragm. If valve sticks, clean or replace as necessary.
2. Apply 8 inches Hg vacuum to valve with engine at idle. Ensure valve stem moves and engine idle roughens.
3. Trap vacuum and hold in valve. Vacuum must not drop more than 1 inch Hg in 30 seconds.
4. If vacuum test is satisfactory but engine idle does not roughen, clean air passages.

Seat Test
NOTE:This test should be performed when the valve is suspected of leaking in the closed position, indicated by rough engine operation.
1. Install blocking gasket (no flow holes) between mounting and valve, then retighten valve.
2. Improved engine operation indicates a defective valve. Clean or replace as necessary.