1978 Saab 99 BaseFACTORY OEM SERVICE PROCEDURE

Delay Valve

Connect tachometer and timing light to engine. Start engine and allow to idle. Quickly open throttle valve and let engine run at 3000 RPM. Check ignition timing. The delay valve should open after 4-8 seconds (ignition timing should advance). If not, replace delay valve.

NOTE: The White end of delay valve should be toward the vacuum control unit of the distributor. Also make sure that the shorter hose is between the valve and the vacuum control unit of the distributor.
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.