TunedPort-Z

So.. I've been working on my 86 Iroc Lb9 off and on for years. The car has cat back, headers, small cam, free mods etc. I'm trying to get this thing running but I need some help. About 2 years ago the fuel pump died and replaced it with the walbro 255. While I had it down I removed all the injectors and found one with a cracked face so I got some used LT1 injectors off of ebay to throw in. (I don't recall if they were 22 or 24 lb, but i did verify they worked) So I put the thing back together and went to start it and got a huge garage rocking backfire complete with ringing ears. I replaced the plugs and wires, and quadruple checked they were going to the right place. Today I hooked up a fuel pressure regulator and just let the pump prime, the fuel pressure shot up to about 35psi and then slowly leaked down to 10 after about 2 mins. Now I DID NOT attempt to start it, my question is 1) did I screw the pooch putting in the lt1 injectors? 2) is it normal for the fuel pressure to leak down after the pump primes but the care is not running? I really want to try starting it again, but I don't want a repeat of next time. Oh, and the car did run before the fuel pump died so timing shouldnt be an issue and i even verified TDC on the #1 cylinder. Thanks for any help.

Tuned Performance

iTrader: (92)

Sounds like you might have a stuck open injector or two. You should run through a few primes then pull the plugs to see if any are wet.
The lt1 injectors are poor in design multec windings often short. They will flow more than what a stock lb9 needs.