LS Engine in K5 - Purge Fuel Rail of Air???

[PWagon]

I recently replaced my leaky fuel rail connector (the tube that connects the two fuel rails together). The picture below still shows the old rusty one. Anyhow, since then my truck runs real rough, has a check engine light, and runs rich at the tail pipe. Autozone scanned my codes and it says I either have a vacuum leak or a faulty MAF sensor. Long story short, replacing the MAF didn't fix it, and I can't find a vacuum leak anywhere. Would pockets of air in the fuel rail connector tube cause this behavior in the engine? If so, how do you fix it?

 

[496truck]

Reaching for solutions? It's not air in the fuel line. What's the pressure in that system, 40-60 psi? That would have purged any air in that rail right through the return line or the injectors real quick. And that valve is there for fuel system pressure testing, not to bleed air from the system.

Ran good before you did the repair, ran bad after? Recheck your work.

Sorry I don't have a better answer.

 

[paratrooper307]

FI systems are self-purging. Did you only change out the crossover? Make sure that everything is seated and the o-rings (If you removed/loosened the fuel rails) aren't pinched or damaged. Check the engine vacuum with a gauge. Hook up a fuel pressure gauge as well. Low pressure can cause some of the symptoms you are talking about, and if the system isn't sealed, pressure can leak down. When my pump relay on my Corvette started to crap out, the pressure dropped and the engine ran very rough.

Just check over everything, it's real easy to potentially damage a part or forget to hook something up after finishing a job.