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 MANUALSFORD1991CAB & CHASSIS 5.8 H, AUTOMATICREPAIR AND DIAGNOSISENGINE PERFORMANCESYSTEMEGR FUNCTION TESTINGTESTINGPORTED EGR VALVE
1991 Ford Cab & Chassis 5.8 H, Automatic
Ported EGR Valve
1991 Ford Cab & Chassis 5.8 H, AutomaticSECTION Ported EGR Valve
- Check vacuum hoses for correct routing. Connect a vacuum gauge directly to EGR vacuum source. With engine running, open throttle. If gauge indicates vacuum, EGR vacuum supply is okay.
- If gauge indicates no vacuum, EGR vacuum port is plugged. Disconnect vacuum hose at EGR valve, and plug hose. Connect a vacuum pump to EGR valve.
- Start engine. Apply 6-10 in. Hg to EGR valve. Engine should run rough or stall and EGR valve should hold vacuum. If engine speed does not change, check for plugged EGR passages or faulty EGR valve.
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.