Ok, so I installed an adjustable fuel pressure regulator and started the car up and could only get a maximum of 6.5 psi, which I was content with and left it at that. After the car warmed up it dropped to 3.5 psi. Why and how is this pressure dropping after the car warms up? This is not a performance pump it's a stock one for a 350 that I bought to feed the 4776 holley on the L69 so it does have a return fitting as well. Also, after it was down to 3.5 psi and took it for a ride and came back it was reading like .5 psi. I'm a little confused by this. Is is possible that b/c of the low pump volume ( 29 GPH) it won't keep pressure? The pump is brand new and the gauge is as well. Thanks!

 

If you're talking about a mechanical pump, they are self-regulated to around 6 psi.

 

yep a manual fuel pump on the engine doesnt need a regulator. unless you want to run lower.

 

I have read that the mechanical pumps are self regulated but wanted to be sure that the fuel pressure did not get any higher than 7psi. Not that it should but, sort-of just a fail safe / future mod kind of deal. What I'm baffled by is why the pressure drops off to virtually nothing as the engine is warmed?

 

Take the regulator out and see if it still does that. If it does, the pump is bad.

 

Ok, I could take it out and try or what would be the difference of backing the adjustment screw out to provide no restriction? If this pump turns out to be junk and I have to buy another ( I would hope not since it's new and the car runs fine - but nothing else makes any sense.) what kind of pump should I grab? Does anyone run one of those summit 80 gph pumps? And if I go to a 2 line pump what do I do for the return line? Plumb it to the other side of the regulator?

 

If your engine is running fine it is probably your guage. I had a brand new guage from Summit do that. When it got hot it wouldn't give an accurate reading at all.

 

hey man im tryen to convert my fuel injeted iroc to a carb how do i do it or what do i need

 

hey guys im tryen to convert my fuelinjected 1989 iroc z to a carb what do i have to do and what do i need can you guys help me

 

https://www.thirdgen.org/carbswap read that then do a

 

Anyone know what a "good," gauge would be to purchase? I had a Mr. gasket one previously and it would spike rapidly from 3 to 10 psi. This one is the summit liquid filled. Holley maybe???

 

did you take out the external regulator yet.

 

I did not remove the regulator, I did back the adjustment way off so I fail to see how this would cause any issue whatsoever. If anything it would just prevent a non-existable pressure spike from occuring. What's everyone have for gauges? I want a good one!