Test 17 - EGR System Check
- Connect tachometer to engine. Disconnect vacuum hose from EGR valve. Connect vacuum pump to EGR valve. If equipped, disconnect and plug vacuum hose at solenoid kicker. Start engine, momentarily raise engine speed to more than 1100 RPM and then wait 2 minutes for idle speed to stabilize. Very slowly apply vacuum to EGR valve.
- Engine speed should begin to drop when applied vacuum reaches 2-5 in. Hg vacuum and continue to drop as more vacuum is applied. Engine may stall before 5 in. Hg of vacuum is applied. If engine speed drop is okay, proceed to step 3). If engine speed does not drop or engine speed does not drop until there is 5 in. Hg or more vacuum, replace EGR valve.
- Disconnect EGR hose. Connect vacuum gauge to EGR vacuum hose. Slowly increase engine speed. As engine speed increases so should the reading on vacuum gauge. If vacuum reading is okay, check the EGR tube attaching nut on the bottom of the intake manifold for a vacuum leak. If okay, proceed to TEST 18 . If vacuum is not okay, proceed to step 4).
- Turn engine off. Remove connector from EGR CVSCC valve. Connect vacuum pump to either port of valve. Try to apply vacuum. Vacuum should not hold with engine coolant above 125°F (52°C). If vacuum does not hold, check EGR signal hose from carburetor for leaks or restrictions. If vacuum holds, replace EGR CVSCC valve.