fuel pressure specs

[goldencalf]

What are the fuel pressure specs for a 97 ranger? Chiltons says 35-45 lbs engine not running. Im wondering what it is at an idle, then in park at say 3k rpm. For what it's worth... Im getting 26-28lbs tops. I hope someone has somethin.

 

[goldencalf]

Please

 

[rwenzing]

1997 and earlier Ranger EFI:

• At 20" vacuum (sea level idle in park/neutral), it will be roughly 30 PSI.
• At 3000 in P/N, engine vacuum would normally be higher than at idle so the fuel pressure may dip below 30 PSI.
• At zero vacuum (WOT under load or engine off), the pressure is usually about 39~40 PSI. This can be simulated at idle by temporarily removing and plugging the vac hose to the fuel pressure regulator.

These are very general estimates so don't be too surprised if your measured pressures are a couple of PSI higher or lower than any of them.

 

[goldencalf]

thank you very much! would driving at 30-40 mph on up to 70mph be considered "under load"

 

[rwenzing]

Yes, but you won't have zero vacuum to the pressure regulator until the the throttle is near or at wide open (WOT).

 

[goldencalf]

ok, thanks again. thing is, truck SOMETIMES gets all stupid accelerating from 30 mph on up, and SOMETIMES will continue to shudder and shake even maintaining 45mph on up. stupid thing. So im trying to rule out a weak fuel pump.

 

[rwenzing]

Clogged fuel filter, dirty injectors, dirty MAF, water in fuel, weak pump, ignition problems all possible.

 

[goldencalf]

yeah, I have fuel filter ruled out as i have changed it. It hasn't popped any error codes yet. So I dunno.