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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSBUICK1986SKYLARK LIMITED, 3.0 LREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSIS2.5L TBI TESTS W/CODESCHART A7 - FUEL SYSTEM DIAGNOSIS (A/F/J/N/P BODY)
1986 Buick Skylark Limited, 3.0 L
Chart A7 - Fuel System Diagnosis (A/F/J/N/P Body)
1986 Buick Skylark Limited, 3.0 LSECTION Chart A7 - Fuel System Diagnosis (A/F/J/N/P Body)
NOTE:
Continued from CHART A5.
- Pressure below 9 psi falls into 2 categories:
- If regulated pressure is less than 9 psi and volume to injector is adequate, system will run lean and cause Code 44. Engine will be hard to start when cold and have poor overall performance.
- A restricted fuel flow is causing pressure drop. Normally, a vehicle with fuel pressure of less than 9 psi at idle will not be driveable. However, if pressure drop occurs only when driving, the engine will surge then stop as pressure begins to drop.
- Restricting the fuel return line allows the fuel pump to develop its maximum pressure. When battery voltage is applied to pump test terminal, pressure should be between 13 to 18 psi.
- This test determines if high fuel pressure is due to a restricted fuel return line or a throttle body pressure regulator problem.
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.