7.3 IDI Bogging Issue

[brandmid]

1989 F450 Super Duty 7.3 5 speed

It's my rollback that's giving me issues, I know it has no way of telling what gear I am in but I feel it more in 3rd gear it seems very sluggish and starts to kind of surge. This happens on both tanks but if its happening on the back tank and I switch it to the front tank it does fine then I switch back to rear and all is good for a little bit.

What could be causing this problem?

 

[Greg5OH]

sounds like air intrusion, perhaps around the FSV?

 

[brandmid]

I was thinking maybe air is getting in but if that were the case wouldn't I be experienced fuel leak down when I left the truck sitting a few days?

 

[ifrythings]

When it does this, try removing the gas cap on the tank, if you get a hissing like air trying to get in then you may have found your issue, if this does happen the breather on top of the tank is plugged and will need cleaning.

 

[Tim4]

Does the shrader valve on the filter head spit a bunch of fuel when you depress it at idle?

A fresh fuel filter is my first choice for your symptoms and then maybe a lift pump.

The surge would indicate air but filters and lift pumps are both cheap.

 

[brandmid]

When it does this, try removing the gas cap on the tank, if you get a hissing like air trying to get in then you may have found your issue, if this does happen the breather on top of the tank is plugged and will need cleaning.

Actually when I re fueled yesterday I did get a hissing sound from the front tank

 

[brandmid]

When it does this, try removing the gas cap on the tank, if you get a hissing like air trying to get in then you may have found your issue, if this does happen the breather on top of the tank is plugged and will need cleaning.

Does the shrader valve on the filter head spit a bunch of fuel when you depress it at idle?

A fresh fuel filter is my first choice for your symptoms and then maybe a lift pump.

The surge would indicate air but filters and lift pumps are both cheap.

I'll check the fuel at idle today and get back to you

 

[Agnem]

I'd recommend adding a fuel pressure gauge to your instrumentation. That would help take a lot of the guesswork out of this.