I have a 92 pickup with a 3vz. I recently took the upper plenum off to replace the injector seals. Now it doesn't start properly, it takes about 5 to 10 cranks before it will start. Once started it runs fine. Before I replaced the injector seals it started perfectly fine. Not sure it is a fuel pressure problem, or a vacuum problem.

I also replaced the driver side fuel rail because it had a small crack.

 

Sounds like you might have accidentally left the cold start injector disconnected as a result of having things apart.

 

I already checked that. I am stumped.

 

I would still go over very carefully EVERYTHING you disassembled to get the plenum off. I've never taken mine off, but I've looked at the FSM and know it's pretty involved. If it was starting well before you worked on it, it's highly likely the problem was caused by something you didn't get back together correctly.

 

Fuel line isn't holding pressure, you can test that at the regulator(it won't be a lot of fun to get at without pulling the plenum, but it's doable). Maybe a wrong vacuum line hook up, or a loose fuel connection sucking air(remember air fits where fluid doesn't).

Here is a vacuum map I colored thelines to make tracing easier.

 

Ok so I just went out and started it, and it idled at about 1800 for a bit then it dropped back down to a normal idle. Which leads me to believe that the csi and switch are working properly. I checked over the vacuum lines before I started it, and they are all hooked up properly. I also checked the gas cap, which when opened had no vacuum. That has always had vacuum when opened. Wondering if it just wasnt closed tightly.

Going to let it cool down and try it again later.

 

Still having troubles with this. Took the upper plenum off today to make sure everything was right on it, and it still is rough starting. All gas lines are tight and not leaking, injectors are all sealed properly and not leaking. I am very confused.

 

I had also pulled the codes and there was a 14, 41, and a 52.

 

Getting so frustrated with it I am contemplating just swapping in a chevy 5.3

 

14 = ignition signal
41= throttle position sensor
52=knock sensor

my guess is the knock sensor harness got damaged when you took off the the plenum. so you will need to replace that. the majority of the time its the harness not the sensor itself but nobody wants to tear apart the intake more then they have too. check your TPS as well