How to remove fuel rails?

[guitarfish]

I'm in the planning stages of a UIM/LIM replacement. I have never removed the fuel rails before, I'm unclear on exactly what I'm supposed to do to get them out of the way.

First - how does one relieve pressure in the fuel line?
Next - do I remove each fuel injector from the manifold, then lift the rails up? How are the injectors removed? Or is there something different I should do?

Thanks!

[GPFred]

It would help to know what model and year your GP is, and what engine you have.

I did my fuel injectors back in September I believe. I have a 2000 GP with a 3.1. I released the fuel pressure by letting it sit overnight. You'll need to drain off some antifreeze so that you can remove the plenum without losing antifreeze all over the engine and into the intakes.
Then after getting the plenum off and other things out of the way, disconnect the main fuel line from the fuel rails. There is a couple of bolts holding the rails to the lower intake manifold. Carefully pry off the rails and fuel injectors as a whole unit. You will have to replace the seals on the injecotrs when you put it back together. The injectors can be removed from the rails by pulling on them carefully. The electrical connectors to the injectors have plastic lock pieces on them that have to be pulled up to disconnect the connectors on the injectors. There should be a connector for the fuel injector bundle that you can disconnect before you lift the rails out.
Hope this helps. You should have a repair manual on hand as well to guide you. Good Luck.

[guitarfish]

Oops, sorry, it's a 97 GP with 3800, no SC. Thanks for the info.

[GPFred]

I forgot to mention there is a kind of clamp that holds the injectors to the rails that have to be removed before you can take the injectors out of the rails.

[BNaylor]

The most convenient way to bleed off fuel pressure is to remove the fuel pump fuse while engine is running and let the engine consume what is left of the fuel in the lines. Other options are at the fuel filter or the Schrader valve located at the fuel pressure regulator.

On a SII 3800 you will have at least three retaining nuts at three brackets on the complete fuel rail assembly. Once they are removed you will pull up all as one piece. The fuel injectors will pop out of the bosses in the lower intake manifold. It is up to you whether you want to remove the fuel pressure and return lines from the rail. You do not have to but you will need a fuel line removal tool. I would leave the fuel lines connected and tie the fuel rail up with some string. Before removing fuel rail make sure all rear bank spark plug wires are out of the way. Also, disconnect the electrical connectors to each fuel injector, any sensors that need to be disconnected and get all wiring harnesses in the way moved for clearance.

The fuel injectors will remove from their location on the fuel rail by removing the clip at the top of each fuel injector. It is recommended to replace both upper and lower injector o-ring seals with new ones.

[guitarfish]

Excellent! Thanks.

[guitarfish]

I am shopping for a replacement plenum.

Do the Delphi or Dorman plenums come with the modified "stovepipe", the metal tube runs up from the intake manifold?

I called my Ponitiac dealer, they only sell that piece with the modified plenum. They said it runs around $150, so I'm wondering if I should go with GM instead of aftermarket.

[BNaylor]

I would go with the Dorman Kit, PN: 615-180. It has the improved plenum, reduced diameter EGR stovepipe, and gaskets, etc. If you go with the GM plenum I believe you will need the UIM gasket GM part # 89017554. GM UIM plenum part number is 89017272. Another popular aftermarket brand UIM is APN which has a smaller EGR stovepipe than the Dorman. The Dorman Kits run around $130-$150 complete.

For LIM gaskets GM has the new aluminum framed ones out now. GM part # #89017816.

[guitarfish]

Thanks a lot bnaylor. I'm going to go with the Dorman. I stopped at the dealer on the way home, which was somewhat disappointing. They had the plenum, opened it up - nothing but the plenum. They didn't have the gaskets in stock. When I asked about the stovepipe, they drew a blank - apparently they don't make a modded one.

There's also two different designs of LIM gaskets, one with locating pins, one without. Mine's an early '97, we haven't figured out which one I need yet.

Q - How is the old stovepipe removed from the intake manifold? A mallet or something?

Thanks.

[BNaylor]

Good choice on the Dorman. GM did have a modified EGR stovepipe for '97-'98 models but it was part of the LIM repair kit. It is listed in the first TSB in that PDF file I sent you earlier. But I would pass on it since you will not need a complete LIM with the Dorman Kit. I would recommend checking to make sure the LIM is true at the flanges before re-installation. It may need to be milled but hopefully it will be OK.

As to old EGR stovepipe removal, it is a press fit so mallet, vice grips or any method that works for you. Good luck.

[guitarfish]

Many thanks bnaylor. A few more Q's if I may...

I'm looking at either Permatex hi temp Ultra Black or Red for the LIM. Either one OK?
*edit* - nevermind - the FelPro LIM kit comes with RTV.

When it comes to RTV application, I'm a little unclear on exactly what areas of the gasket to apply it to.

Once I apply the RTV, do I set the gasket in place and reassemble right away? I've read about a "setup time" of 30min - I assume they mean before the engine is running?

[richtazz]

The RTV is only used where the side intake gaskets meet the end seals on the 3800. Do not apply any RTV on the side gaskets near the intake ports, as fuel eats RTV. Allow the RTV to skin slightly (10-15 min) before installation of the intake, to keep it from sticking to the manifold and moving out of position causing a leak. Allow the RTV to completely cure before starting the engine, usually over night.

[BNaylor]

The most important part which is overlooked are both the UIM and LIM bolts. The old bolts will have old threadlocker that will need to be cleaned off so you can re-use the bolts. Or you may replace with new but they are not TTY bolts.

Be advised that GM revised the UIM bolt torque figure in 2004 from 89 in-lbs to 11 ft-lb. The LIM bolts are still 11 ft-lbs. Follow the proper torqueing sequence as seen in the PDF file especially for the LIM. There are 12 LIM bolts and some are different size in length so do not get them mixed up.

[guitarfish]

You guys have been very helpful. I have exhaustively read through every post here on "intake", "manifold", and "plenum". I still have some questions, so I'm just gonna go for it. Here we go...

1. Which LIM gasket set?
There is "1st design - End seals not equipped with locating pins"
and "2nd design - End seals equipped with locating pins". I don't know which one I need. The car in question is a '97 GP with a date of 10/96 on the door sticker. The dealer says he doesn't know any way to tell without tearing down and looking. I will likely end up buying both kits to be safe, unless someone knows how to ID?

2. RTV application
This pic was in the PDF kit. So I should apply RTV like this, lay the gaskets down, then apply in like manner to the other side of the gaskets?


3. Revised UIM torque spec
If GM revised the UIM torque spec from 89 in lbs to 11 ft lbs (which is 132 in lbs), this means the plenum is going to be a LOT tighter than originall spec'd, right? Even tighter than the LIM bolts? I don't want to crack the thing.

4. Injector o-ring kit
GM p/n 12537425 - Lists for $62. Is this a complete kit for all 6 injectors? Dealer wasn't sure.

[BNaylor]

Originally Posted by guitarfish

You guys have been very helpful. I have exhaustively read through every post here on "intake", "manifold", and "plenum". I still have some questions, so I'm just gonna go for it. Here we go...

1. Which LIM gasket set?
There is "1st design - End seals not equipped with locating pins"
and "2nd design - End seals equipped with locating pins". I don't know which one I need. The car in question is a '97 GP with a date of 10/96 on the door sticker. The dealer says he doesn't know any way to tell without tearing down and looking. I will likely end up buying both kits to be safe, unless someone knows how to ID?

2. RTV application
This pic was in the PDF kit. So I should apply RTV like this, lay the gaskets down, then apply in like manner to the other side of the gaskets?

Personally, I'd go with the new aluminum framed LIM gaskets. I do not recall whether the end gaskets in the newest gasket kit are pinned or unpinned. Plus, the coolant passage seals are improved. In the procedure the RTV was added because the older LIM gaskets had a deficency in the area of the coolant passages but it is not necessary to do it with revised LIM gaskets. However, I would apply the RTV to the four corners of the end gaskets as seen in the pic regardless of which LIM gaskets are used.

Originally Posted by guitarfish

3. Revised UIM torque spec
If GM revised the UIM torque spec from 89 in lbs to 11 ft lbs (which is 132 in lbs), this means the plenum is going to be a LOT tighter than originall spec'd, right? Even tighter than the LIM bolts? I don't want to crack the thing.

Were are only dealing with a few ft-lbs difference. If you are going with the Dorman you should have no problems with the 11 ft-lbs. The Dorman UIM plastic is reinforced and thicker. But the decision is yours.

Originally Posted by guitarfish

4. Injector o-ring kit
GM p/n 12537425 - Lists for $62. Is this a complete kit for all 6 injectors? Dealer wasn't sure.

That sounds right to me including what the dealer is charging $$$ which is about retail price. There should be other o-rings in the fuel injector o-ring set like the fuel pressure and return line o-rings and maybe the o-ring for the fuel pressure regulator.