Ok I do not have a fuel pressure guage (ick) but i did do the ultimate TBI mods, and the adjustable fuel pressure regulator mod.

What I need to know is how much to turn the screw it looks like it doesn't move that much per turn, I am tempted to do 3-4 turns.

I know I am lean right now so I need more fuel pressure. I just really don;t want to over/under do it and have to pull the TBI again.

The damned hardware store didn't have any screws/bolts that would fit so i could adjust it without pulling off the injector tower..

also has anyone added spacers on the injector tower to get them up off the TBI, if so does it really make a difference I am thinking of making a spacer, but only if it is going to be worth the effort.. I was thinking a 1/2" piece of plastic.

Thanks in advan ce for your answer you guys are the mod/tbi kings

 

I believe 1 1/2 turns equals 1 psi, however given the wide variation that the stock ones came in, there's no telling where you are now after 3 turns.

Once again, that's my best bet, but my memory starts to slip the later it gets.

 

thanks a bunch went in three turns. we'll se how she goes

 

On the GM vacuum one it is 2.5 turns in for every 1psi. I am not sure if the screws are the same for each unit GM makes.