3.4L LIM R&R Problem

jwelch1103 · 09-24-2007, 06:19 AM

OK, I replaced the LIM gaskets this weekend on my 2001 Impala. When I got everything back together and treid to start it up fuel began leaking. I think the leak is at the fuel rail inlet, or possibly the fuel pressure regulator connection at the fuel rail. SO, I am going to take the engine back down to where I can get at these components. The fuel rail inlet was quite difficult to reattach and I am pretty sure that is where the problem is. I am wondering if the o-ring came out of place while reattaching.
Does anyone have any tips on making this connection? Thanks in advance.
JW

richtazz · 09-24-2007, 06:59 AM

I would bet your leak is at the o-ring where the steel line hooks to the end of the rail (where the 14mm hex line-fitting is). If you don't lubricate that o-ring before reassembly, then it will roll over it's groove and get pinched, causing a big leak.

jwelch1103 · 09-24-2007, 07:15 AM

Thanks for the reply richtazz, I suspect that is where the leak is. I did lube the o-ring, just a light application of engine assembly grease. I will try to use more lube this time, perhaps any residual gasoline may have "cleaned" the grease off as it was being reattached.
I know it required quite a bit of force to remove (after the hex line fitting was disengaged of course), and it was the most difficult piece in the whole job to reassemble. I reused the old o-ring since it looked to be in OK shape. I don't suppose a new o-ring would make it any easier to reattach, but if anyone knows better please tell me.
JW

richtazz · 09-24-2007, 10:40 AM

The most important step is to lube the inside end of the fuel rail, as well as the o-ring (I use engine oil), and make sure you get the line in dead straight (don't force it). When you have it straight, it will require the use of a wrench to install, but it shouldn't have much resistance (it's just enough where you can't turn it with your fingers). I agree that they are a PITA to deal with, difficult to remove and reinstall. I would strongly suggest getting a new o-ring, as it's highly likely the old one is now damaged beyond reuse.

jwelch1103 · 09-26-2007, 05:03 PM

Thanks richtazz for the advice on the fuel rail connection. Like you said, sure enough the o-ring was chewed up and useless when I disassembled the connection. I used motor oil on the inside of the fuel rail and was able to get it sealed (without forcing it!) by keeping the hex nut engaged on the outward side of the collar and letting the hex nut seat the o-ring. It was easy as pie once I used the proper technique!

Blue Bowtie · 09-13-2009, 11:42 AM

Not to open an old can of worms but for archive purposes, I just went through this same scenario. Instead of the O-ring being damaged, I discovered the 14mm hex nut was not completely tight. The nut must be VERY tight to compress the ring properly. It's been holding standing pressure for 45 minutes now that I've I pulled the upper intake and tightened the nut properly.

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