Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Differential Vacuum Delay Valve
1987 Pontiac SafariSECTION Differential Vacuum Delay Valve
- Using a "T" fitting, connect a vacuum gauge in vacuum line from valve to ILC. Connect a vacuum pump to port one of valve. Apply 17.8 in. Hg vacuum to port one and observe gauge. Gauge should read 16.9 in. Hg vacuum within 6-9 seconds. See Fig 1 .
- Remove vacuum gauge and "T" fitting. Connect vacuum pump to port 2 and leave port one open. Air should flow through valve when .5 in. Hg vacuum is applied.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.