What are the 2 screws on the top & back of the pump for

[Cat_Rebel]

You know the ones I'm talking about, they have alittle plastic cover over em. A guy called me & asked what they did, said he turned one of em in about 2 turns & it upped his idle & seemed to make it run smoother. But he backed it off a turn went to normal & said it's running fine. It's a 93 F250 with a aftermarket ATS turbo added on it with 130k miles.
I just would like to know what he touched, they had the little plastic covers over em.

 

[redneckaggie]

one of them is low end fuel delivery and the other is a no no to touch dont remember which was which but the na pumps only have the no no and the turbo pumps have both.

 

[tractorman86]

yup, the no no one is the shaft for the idle and govenor. ask mel, BIG NO NO

 

[1dieselman]

The upper screw that uses a 1/8" allen wrench is the torque screw ( or lower end fuel delivery) it can be backed out 4 turns, in fact that is ATS's recommendation when installing their aftermarket turbo kit on the 92-94 serpentine belt engines

 

[sootman73]

they really dont do anything! i messed with em both and got no difference anywhere in the rpm range. fine to want to know what they are but dont waste your time messing with them. my idle is at 800 cuz i touched one and didn't change it back. didn't make a difference in smoke, power, or throttle response.

 

[Cat_Rebel]

The upper screw that uses a 1/8" allen wrench is the torque screw ( or lower end fuel delivery) it can be backed out 4 turns, in fact that is ATS's recommendation when installing their aftermarket turbo kit on the 92-94 serpentine belt engines

You ever messed with it personally or just something you heard? I still have a NA pump with a turbo.

Like I said the guy told me he changed the idle on the truck so set it back to where it was. So I assume that everything is good & tell him to leave it alone?

 

[1dieselman]

You ever messed with it personally or just something you heard? I still have a NA pump with a turbo.

I have read it in the ATS documentation.
I have it backed out 2 turns on mine. It made a little difference but probably not as much as the internal adjustment would.

 

[tknomaj]

My HYPERMAX Intercooler kit has Instructions to turn those screws but do not recall which way will check tomorrow and let you know