F. Check EGR Vacuum Amplifier

F. Check EGR vacuum amplifier
(engine warm)

1. Check venturi vacuum*





- Remove red vacuum line from throttle body and connect to T-piece of vacuum test gauges. Attach short vacuum hose from T-piece to throttle body.
- Start engine and let idle (engine at operating temperature).
- Press button on vacuum test gauges to read vacuum (read left gauge).
^ must be at least 13 mbar (0.38 in HG)*
^ If NOT, check vacuum tube in throttle body for obstruction and correct
- Increase engine speed to 3500 RPM.
^ should read up to 23 mbar (0.6 inHG)(read left gauge)*
^ IF NOT, check vacuum nozzle on throttle body for obstructions and correct
- Turn engine OFF.

2. Check for vacuum signal





- Connect T-piece from vacuum test gauges to red vacuum line and connect vacuum pump to other end of T-piece.
- Start engine and let idle.
- Press button on test gauges to read vacuum.
- Activate pump until vacuum reads
^ at least 23 to 27 mbar (0.6 to 0.8 in HG), idle must be noticeably erratic.
^ If NOT, look for vacuum leaks at red, blue and yellow line connections and correct as necessary.
^ If vacuum line connections are OK, replace EGR vacuum amplifier.
- Turn engine OFF

3. Check EGR vacuum amplification





- Connect vacuum test gauges between EGR vacuum amplifier and blue line to EGR thermal vacuum valve (EGR TVV), using the supplied T-piece.
- Start engine and let idle.
- Measure vacuum.
^ must read at least 71 mbar (2.0 in HG) at idle (read right gauge) but NOT MORE than 100 mbar (2.9 in HG)
^ If NOT, replace EGR vacuum amplifier
- After replacing EGR vacuum amplifier, recheck vacuum specifications.
- Turn engine OFF

4. Check EGR Thermal Vacuum Valve (TVV) function





- Remove hose from yellow line at EGR TVV.
- Connect vacuum test gauges to hose from EGR TVV (yellow line).
- Start engine and let idle.
- Measure vacuum.
^ must read at least 71 mbar (2.0 in HG) (read right gauge)
^ If NOT, replace EGR TVV
- After replacing EGR TVV, recheck vacuum specifications.
- Turn engine OFF

Note
Before proceeding to next step, make certain that all vacuum hoses are correctly routed and securely attached.