Okay, today the plenum and runners came off. I pulled the fuel rail, replaced the uppper and lower o-rings, installed washers under the fuel rails (I have the Edlebrock intake), I even replaced the O-rings on the metal fuel lines that run behind the alternator that connect the fuel rails and the flexible gas hoses. (man, those were ugly!) Guess what, my pressure still drops quickly after engine shut down. Any other ideas? Like I said the injectors were are LT1 #24 and were recently serviced by Rick at Cruizin performance.

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Rob P
89RSconvtZZ4TPI
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Could be one of two other places (or maybe both?)...pressure regulator or fuel pump check valve.

I know you said you got the injectors serviced...but did you double check anyway it's not them leaking down? Did you pressurize the fuel rails before you bolted them down in place to see if they were leaking down?

I also bought LT1 24# injectors but haven't installed them yet. I will also send them to Cruzin...I hope it'll fix my leakdown problem too.

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1989 IROC-Z, ZZ3 shortblock with some bolt-ons.
13.20 @ 108.69, 2.2 60'

 

Try Blocking off the fuel return line that will let you know if the problem is upstream or down stream of that point. I believe if you activate the fuel pump twice in a row with the fuel return line blocked and the pressure stays the same it is more than likely the regulator. If not it maybe the injectors. Pull the fuel rail up and take a look. If the pressure stays good then it maybe that the fuel pump check value is bad or something else downstream.

Hope this tinny bit of info helps.

Ant

 

where is it leaking to? is the gas going into your oil? if so then its an injector/electrical problem. if the gas is returning back to the tank then its a fuel pump problem.

 

I have no external leaks, so if it was the adj FPR or somewhere on the fuel rail I'd see fuel. Unfortunately I was stupid and did not reconnect the fuel rail with it off the intake and see if any of the injectors were leaking down. I really suspect its bleeding pressure back to the tank.
But I did get to polish the plenum up nicely. Looks like chrome now. Thanks guys.


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Rob P
89RSconvtZZ4TPI
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

See this thread for my fix.
https://www.thirdgen.org/messageforu...ML/000338.html



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86 Camaro Sport
383 Speed-O-Motive Crate Engine, Trick Flow Heads, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Dynomax Cat-back, Serpentine belt setup.

http://64.176.105.239/octride.htm