Fuel pressure and volume

[Rock]

Having a problem with power loss.84 F250 Changed fuel filter still power loss. Hooked up a combination pressure and vac. gauge to schrader valve. Results were 3lb. cranking 3.5lb. at idle. Increase rpm and would drop to the point it would pull about 5lbs. of vaccume at 2000 RPM. Volume test was 3.5oz. before filter head and 2oz. at schrader while cranking for 10 seconds.Fuel pump was changed about 500 miles ago. Please help.

 

[icanfixall]

Did the fuel pump arm install over the cam lobe... If it did the stroke will be smaller so it will pump less... also to get the correct amount of fuel during cranking you need to remove the injection pump feed line and test from the filter outlet. Not thru the schrader valve... that can't flow enought for a proper test volume...

 

[Rock]

Did the fuel pump arm install over the cam lobe... If it didn't the stroke will be smaller so it will pump less... also to get the correct amount of fuel during cranking you need to remove the injection pump feed line and test from the filter outlet. Not thru the schrader valve... that can't flow enought for a proper test volume...

Thanks, If I remember correctly 10 seconds of cranking should yield about 5oz,

 

[Rock]

Did the fuel pump arm install over the cam lobe... If it didn't the stroke will be smaller so it will pump less... also to get the correct amount of fuel during cranking you need to remove the injection pump feed line and test from the filter outlet. Not thru the schrader valve... that can't flow enought for a proper test volume...

What about pressure can't that be checked at schrader valve?

 

[icanfixall]

Yes... The fuel pressure can be checked at the schrader...

 

[OLDBULL8]

Did the fuel pump arm install over the cam lobe... If it didn't the stroke will be smaller so it will pump less...

Gary; shouldn't that have been "did" instead of "didn't" ?

With the new straight arm, you have to be careful to put it under the cam, if it's the dog leg just shove it straight in.

 

[icanfixall]

Yes bull... I made a messy... I fix....

 

[Rock]

Yes... The fuel pressure can be checked at the schrader...

I mentioned at around 2000RPM The gauge was reading about 5" of vacuum At about 1500 Rpm it was only reading 2lbs. of pressure. Where should the pressure read at idle and about 2000RPM? Thanks for your help on this.

 

[Exekiel69]

I would put that gauge after the filter using a T to check the fuel pressure, I have a fuel pressure gauge on every diesel I own bc of this same problems. Remember this pumps are lubed and cooled by diesel fuel so You want to have enough fuel at all times.