If so how is it adjusted...?

I'm putting in 24# injectors and I'm at 45 psi max now. Need to know how to adj. it up or down to tune. There is a nut with a screw in the middle of it in the cover plate. It looks to be all the way in or clockwise. I tried loosening the nut and backing the screw out (counterclockwise)but the screw felt loose and I wasn't sure what the heck I was doing so I put it back the way it was. Afraid to spring a leak if the screw came out.

Can anyone tell if this is Adj. and if so what kind it is and how to adjust it. I think I've seen some of these in pics of other's cars on here. Hopefully one of you will know.

Please help, Friday is track night!!! I've got a Conv. 25th Anniversary T/A (stroked 383) to take a spankin from the iRoc!!!

Thanks,
Tim

 

That is an AFPR. That hex nut under the screw head isn't supposed to be there. Its not threaded onto anything which is why it felt loose. Remove the hex nut and turn screw clockwise to increase pressure. Oh, yes - I would bleed off the residual pressure in the fuel system (if there is any) at the schrader valve before removing the screw to get the nut off and not go much more than 50 PSI at WOT.

 

Just to be sure, the nut didn't feel loose, the screw felt loose. But that is because it is so far out?

I just want to be sure before I pull it off and re-pressurize it.

Have you had one like this?

Thanks again,
Tim

 

All AFPRs are the same design. Never seen on ewith a nut on the adjustment screw before but I guess it makes for an easy fail-safe stopping point. The screw should have some tension on it (if your pressure is set above stock) because the spring/plate mechanism inside should be putting resistance against it. If there is not any tension on the screw you may want to consider buying a new AFPR housing ($60 - Crane Cams). A loose screw would probably work its way out from vibrations.

 

Some AFPRs have a locking nut on them. My BBK one has a design like this for instance..... Some designers create a setup where the tension on the adjusting screw will hold it tight, but I tend to trust using a nut to lock it down much more. That looks like a TPIS one but they don't have locking nuts on them, so........

 

I appreciate all the advice guys. I'm changing the injectors today so I'll have room to play with it now that the Plentum is off. I'll let you know what happens. Wish me luck....First time replacing injectors myself.

Tim