I have '88 fuel injected 6 cylinder (4.9 L). It started stumbling when idling and after a very short drive, it now won't start. Replaced the fuel filter, still no start. I have a fuel pressure tester but can someone please tell me what the pressure ranges are supposed to be when starting and when running? Can't seem to find a reliable source online or in my book.

Also, where is the fuel pressure regulator? I see where the fuel lines go to the top of the back of the engine to what looks like directly to the fuel rail?

Thanks for the help!

 

pressure reg is on the return side, built into the fuel rail. should see anywhere 45 to 60 psi for the 4.9. it will rise a few psi when when intake vacuum drops or the vac line is disconnected from regulator.

 

which is on the opposite side of the spark plugs right?

 

the entire fuel system, yes, is on the rh side of the engine. the spark plugs are on the lh side

 

What book are you using?

Read this caption, & the NEXT 2; then go back to the first one & follow the link to the fuel reservoir album:

(phone app link)


This explains the FPR:

(phone app link)


This shows it, near the bottom center of the pic with a Red vacuum line:

(phone app link)

 

Your 88 should have 45-60 psi of pressure from the shrader valve. The pressure should hold for a long time after shutdown and not bleed down right away. Do not change out the pressure regulator UNLESS raw fuel is present at its vacuum connection.If there is no fuel present there, the regulator is good. Most people don't know the regulator's job is to keep the fuel pressure from going too high.