Need help with 91 L98 fuel rail leak
08-31-2013, 04:58 PM
#1
Race Director
Thread Starter
Need help with 91 L98 fuel rail leak
(almost) new Bosch III injectors from FIC. Even though their web site says these are the same length as the ones I removed I don't think so.
I installed a rebuilt TPI system and used new O rings from Autozone. I had multiple leaks. I compared these O rings to the ones that were on the injectors and they were not as thick and not as pliable.
I ordered new O rings from FIC. Thoroughly cleaned everything and made sure there were no nicks or scratches in the fuel rail openings or at the intake manifold. Lubed the new O rings up good and oh-so-carefully installed the injectors into the fuel rails.
Put everything back on last night but found the #6 injector to be leaking at the manifold. Recharged the battery overnight and noticed that the #6 and #8 injectors are sitting quite high in the intake manifold. Pulled them down a bit with pliers but then had leaks at the fuel rail for both injectors.
Pulled things apart and decided to place an additional O ring in the fuel rails at #6 and #8 before installing them back into the rails. There is plenty of room in the bores of the fuel rails for the extra O ring so we thought this might solve the problem.
Put everything back together and - #6 is still leaking.
I am ready to burn the dang car to the ground. So freaking pizzed off now. The GM engineers that designed the TPI system should be drawn and quartered!
:reddev il
Whew - thanks for letting me rant. Feel better now.
FIC has these in their catalog. They aren't open right now so I was hoping to get some answers here.
http://fuelinjectorconnection.com/sh...?productid=180
I am pretty sure that my problem is that the injectors are not long enough to fill the space between the rails and the intake manifold.
All O rings are new and were they were lubed up good with motor oil and the injectors were pushed in straight without twisting them.
I am sure we got them in correctly.
Thanks for any help and insight. I am at the end of my rope until I can speak with FIC on Tuesday.
I installed a rebuilt TPI system and used new O rings from Autozone. I had multiple leaks. I compared these O rings to the ones that were on the injectors and they were not as thick and not as pliable.
I ordered new O rings from FIC. Thoroughly cleaned everything and made sure there were no nicks or scratches in the fuel rail openings or at the intake manifold. Lubed the new O rings up good and oh-so-carefully installed the injectors into the fuel rails.
Put everything back on last night but found the #6 injector to be leaking at the manifold. Recharged the battery overnight and noticed that the #6 and #8 injectors are sitting quite high in the intake manifold. Pulled them down a bit with pliers but then had leaks at the fuel rail for both injectors.
Pulled things apart and decided to place an additional O ring in the fuel rails at #6 and #8 before installing them back into the rails. There is plenty of room in the bores of the fuel rails for the extra O ring so we thought this might solve the problem.
Put everything back together and - #6 is still leaking.
I am ready to burn the dang car to the ground. So freaking pizzed off now. The GM engineers that designed the TPI system should be drawn and quartered!
:reddev ilWhew - thanks for letting me rant. Feel better now.
FIC has these in their catalog. They aren't open right now so I was hoping to get some answers here.
http://fuelinjectorconnection.com/sh...?productid=180
I am pretty sure that my problem is that the injectors are not long enough to fill the space between the rails and the intake manifold.
All O rings are new and were they were lubed up good with motor oil and the injectors were pushed in straight without twisting them.
I am sure we got them in correctly.
Thanks for any help and insight. I am at the end of my rope until I can speak with FIC on Tuesday.
08-31-2013, 07:17 PM
#4
There is no problem. Its a simple matter of assembly technique.
Yes, the B-IIIs are a hair shorter and some people use 2 --rings at the bottom but its NOT necessary. The NEW o rings are made of a stiffer alcohol resistant material called Viton. Its the "go-to" material for seals and O-rings these days. Rubber rings harden and leak...causing many car-b-ques.
Nissan had a huge recall many years ago when the U.S. started using alcohol in gasoline...aka gasahol. My 300zx got a factory fresh top end free of charge...all new fuel system....all alcohol compatible. The luck of good timing..
Anyway, putting the rails together takes a little patience. I'll start from scratch on how I've done it and NEVER had a leak.
Take each tube and every piece apart. Wash and wipe dry and de-bur the tube flares and edges with fine emory. No sharp edges or nicks allowed.
Now, lay all the parts on the table as they should go together.
use Vasoline to assemble. Slip O-rings over the tube end and leave plenty of vasoline. For sections that have retainers, stick the sections together and tighten down. At this point it is critical that you do not twist the tubes inside the rails once assembled.
When the whole rail is assembled with fuel regulator in place and ready to set on the intake, place the injectors IN the RAIL and push them all the way up and in. Place the O-rings(s) on the bottom of each injector with a wad of vasoline. Wipe excess vasoline IN the manifold hole for the injector.
Set the rails with inj hanging, down into place and guide each inj tip into place. When ALL 8 inj are in their holes.....
carefully find good places for both hands on the rails and push firmly and hard downward and bounce on the rails to "snap set" the injectors in the manifold seat. You will feel and HEAR the snap or a POP when they are "set" properly.
This is probably where your leaks are coming from, the inj tips NOT being set right in the manifold... You may have to bounce on the rails a few times and do it just right...but that POP is absolutely necessary...no pop, no seal under pressure. The POP is the inj tip being forced thru the smaller oring after its been compressed slightly sitting against the manifold hole. Use vasoline because this lets the tips slip thru the O-rings and NOT roll the O-ring as the tip tries to go thru...if its not well lubed, the o-ring will roll into the hole and not seal or seat.
Once you get the rails down and the injectors seated, put the 4 bolts in, tighten. Get the fuel lines on with those 2 new O-rings and tighten. Install the cold start line and injector if you have that 9th inj.
STOP
NOW is the time to make sure that every fuel line, or part is closed and sealed. Connect the battery and turn the key on off on 3 times to charge the fuel system. Its helpful to have a fuel test gauge on the rails when you do this, but connect it BEFORE you turn the key. We want to be able to smell and SEE any leaks at this point and correct them before final assembly.
Refrain from rotating the injectors after they have been snapped into place. This tears the O-rings. The injectors seal by the tip compressing the rubber against the manifold wall. Under compression the rubber is sealing against pressure BUT its fragile and will tear if its tweaked any. This is also why you leave lots of vasoline in place to help guard against this tearing. The vasoline melts away to nothing-ness the instant that heat appears...that's what makes it perfect for this task.
If you find leaks, its fairly easy to lift that corner and replace the o-ring or pull 1 inj out. Replace and try again.
If you take your time and do it clean and follow those steps, you will not have any leaks. Once you get it dry and tight, finish the assembly and celebrate !
its an afternoon on a L98. 4-6 hrs 1st time....LTs are easier.
I always loosen the lower runner bolts to lay the runners back a bit to give more room to lift and lower the rail set in place. Some prefer to wrestle it around...I like to do it clean and easy...less headache later. With the rails off is also a great time to replace vacuum hose, move some things to make them accessible and even pull the dizzy for inspection and cleaning.
The B-III also does NOT need the clips that were on the stock mule-tic injector.
The up/down position of each injector is not critical and may vary from one to the other because they ARE shorter than the stock. Its not a big deal. If you used 2 rings on the bottom that will help give them all a level appearance.
Moving the injectors after they are "set" in the O-rings is what can cause leaks. Try to have them aimed where they need to be as you set the rails down on the manifold with the inj hanging...its OK to twist them before they are set, after the snap, leave them where they are. Otherwise you risk a leak. Sometimes you get away with a slight twist of one...sometimes NOT.
Good luck ! Hope this helps someone.
Yes, the B-IIIs are a hair shorter and some people use 2 --rings at the bottom but its NOT necessary. The NEW o rings are made of a stiffer alcohol resistant material called Viton. Its the "go-to" material for seals and O-rings these days. Rubber rings harden and leak...causing many car-b-ques.
Nissan had a huge recall many years ago when the U.S. started using alcohol in gasoline...aka gasahol. My 300zx got a factory fresh top end free of charge...all new fuel system....all alcohol compatible. The luck of good timing..
Anyway, putting the rails together takes a little patience. I'll start from scratch on how I've done it and NEVER had a leak.
Take each tube and every piece apart. Wash and wipe dry and de-bur the tube flares and edges with fine emory. No sharp edges or nicks allowed.
Now, lay all the parts on the table as they should go together.
use Vasoline to assemble. Slip O-rings over the tube end and leave plenty of vasoline. For sections that have retainers, stick the sections together and tighten down. At this point it is critical that you do not twist the tubes inside the rails once assembled.
When the whole rail is assembled with fuel regulator in place and ready to set on the intake, place the injectors IN the RAIL and push them all the way up and in. Place the O-rings(s) on the bottom of each injector with a wad of vasoline. Wipe excess vasoline IN the manifold hole for the injector.
Set the rails with inj hanging, down into place and guide each inj tip into place. When ALL 8 inj are in their holes.....
carefully find good places for both hands on the rails and push firmly and hard downward and bounce on the rails to "snap set" the injectors in the manifold seat. You will feel and HEAR the snap or a POP when they are "set" properly.
This is probably where your leaks are coming from, the inj tips NOT being set right in the manifold... You may have to bounce on the rails a few times and do it just right...but that POP is absolutely necessary...no pop, no seal under pressure. The POP is the inj tip being forced thru the smaller oring after its been compressed slightly sitting against the manifold hole. Use vasoline because this lets the tips slip thru the O-rings and NOT roll the O-ring as the tip tries to go thru...if its not well lubed, the o-ring will roll into the hole and not seal or seat.
Once you get the rails down and the injectors seated, put the 4 bolts in, tighten. Get the fuel lines on with those 2 new O-rings and tighten. Install the cold start line and injector if you have that 9th inj.
STOP
NOW is the time to make sure that every fuel line, or part is closed and sealed. Connect the battery and turn the key on off on 3 times to charge the fuel system. Its helpful to have a fuel test gauge on the rails when you do this, but connect it BEFORE you turn the key. We want to be able to smell and SEE any leaks at this point and correct them before final assembly.
Refrain from rotating the injectors after they have been snapped into place. This tears the O-rings. The injectors seal by the tip compressing the rubber against the manifold wall. Under compression the rubber is sealing against pressure BUT its fragile and will tear if its tweaked any. This is also why you leave lots of vasoline in place to help guard against this tearing. The vasoline melts away to nothing-ness the instant that heat appears...that's what makes it perfect for this task.
If you find leaks, its fairly easy to lift that corner and replace the o-ring or pull 1 inj out. Replace and try again.
If you take your time and do it clean and follow those steps, you will not have any leaks. Once you get it dry and tight, finish the assembly and celebrate !
its an afternoon on a L98. 4-6 hrs 1st time....LTs are easier.
I always loosen the lower runner bolts to lay the runners back a bit to give more room to lift and lower the rail set in place. Some prefer to wrestle it around...I like to do it clean and easy...less headache later. With the rails off is also a great time to replace vacuum hose, move some things to make them accessible and even pull the dizzy for inspection and cleaning.
The B-III also does NOT need the clips that were on the stock mule-tic injector.
The up/down position of each injector is not critical and may vary from one to the other because they ARE shorter than the stock. Its not a big deal. If you used 2 rings on the bottom that will help give them all a level appearance.
Moving the injectors after they are "set" in the O-rings is what can cause leaks. Try to have them aimed where they need to be as you set the rails down on the manifold with the inj hanging...its OK to twist them before they are set, after the snap, leave them where they are. Otherwise you risk a leak. Sometimes you get away with a slight twist of one...sometimes NOT.
Good luck ! Hope this helps someone.
Last edited by leesvet; 08-31-2013 at 07:29 PM.
08-31-2013, 10:01 PM
#5
Race Director
Thread Starter
Thanks Lee! I will take everything apart and use Vaseline this time. Some good tips here that should be a sticky!
08-31-2013, 10:09 PM
#6
Its truly a matter of going slow, doing it clean and Checking things twice as you assemble.
I'd bet that 50% of the 1st time inj swaps end up with a minor leak that they have to go back and fix. I'd also bet that most of those leaks are from the missed step of "snapping" the injectors in place. If you just press them down in the manifold, the tips will go down against the o-ring and stay there, never entering or going THRU the O-ring. Being wrapped in rubber is what seals the injector, not resting on the rubber...the seal is self sufficient when its thru the rubber. You CAN easily bolt it up and think its right without having all of the inj tips pushed thru the bottom o-ring. That's what the bouncing on the rails is all about...the sudden force that makes the tip pop thru the tight rubber ring.
It'll work !
Just remember, patience is a virtue !
I don't know what a virtue is, but I'm told its a good thing...
I'd bet that 50% of the 1st time inj swaps end up with a minor leak that they have to go back and fix. I'd also bet that most of those leaks are from the missed step of "snapping" the injectors in place. If you just press them down in the manifold, the tips will go down against the o-ring and stay there, never entering or going THRU the O-ring. Being wrapped in rubber is what seals the injector, not resting on the rubber...the seal is self sufficient when its thru the rubber. You CAN easily bolt it up and think its right without having all of the inj tips pushed thru the bottom o-ring. That's what the bouncing on the rails is all about...the sudden force that makes the tip pop thru the tight rubber ring.
It'll work !
Just remember, patience is a virtue !
I don't know what a virtue is, but I'm told its a good thing...
Last edited by leesvet; 08-31-2013 at 10:23 PM.
09-01-2013, 01:53 PM
#7
Safety Car
Member Since: Jan 2004
Location: Northern California
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Jon's instructions say, to install the injectors into the Intake Manifold First and then into the Fuel Rail.
Also, Jon recommends using Dish Soap instead of Petrolem lubricants to lube the O-Rings. Petroleum lubricants attract dirt and won't evaporate like dish soap will which is what you want.
I've followed Jon's instructions on Three separate Injector installs and have never had a single problem!...
.
Also, Jon recommends using Dish Soap instead of Petrolem lubricants to lube the O-Rings. Petroleum lubricants attract dirt and won't evaporate like dish soap will which is what you want.
I've followed Jon's instructions on Three separate Injector installs and have never had a single problem!...
.
Last edited by GKK; 09-01-2013 at 01:56 PM.
09-01-2013, 05:24 PM
#8
Race Director
Thread Starter
Looks like I will have to call Jon on Tuesday. Have had the rail off 7 times. The last 2 injectors on the passenger side continue to leak at the rail. Cleaned and inspected the opening with a magnifying glass. Appears to be smooth and spotless. Have used new O rings each time and they have been inspected under a jeweler's loop. No cracks or deformities. Have assembled with soap, motor oil and Vaseline. Seated firmly. They appear to seal very well and are difficult to remove as they are quite tight. Sometimes they leak worse than others.
Tomorrow (Labor Day) I will mike the insides of the orifices that I am having trouble with and see if they are larger than the ones that work OK.
If they are too large then I will purchase a used rail from one of the Vette scrapyards. Lord can only guess why they would be too large though.
Tomorrow (Labor Day) I will mike the insides of the orifices that I am having trouble with and see if they are larger than the ones that work OK.
If they are too large then I will purchase a used rail from one of the Vette scrapyards. Lord can only guess why they would be too large though.
09-01-2013, 09:58 PM
#10
These should be brown in color...and fairly fat and stiff.
How many o-ring sets have you gone thru? all the same type?
I guess you have placed O-rings on each inj top and bottom to check the fit...they should slip on with some drag but not much. The ring compresses in the manifold to grip the inj and create the seal.
Did you move the inj around to different holes>??? random placement each time I hope?
if the same holes keep leaking, that would mean the HOLE is the problem, not the inj or the seal.
There ARE such things as "square" O-rings. Search the ph book or google to find a seal shop in your area that might have some. Mic the holes and take an inj and they will fit the o-ring to the application..
One more stupid question....you say #6 leaks every time, you are positive that its the inj leaking and NOT one of the rail joints or the regulator?
I have never heard of this much trouble getting a seal in the exact same hole, this many times after this many attempts....somethings AFU.
The reason I ask if the inj are being installed at random is to be sure the problem is not with a certain 1 or 2 inj, if you are putting a different inj in #6 each time,. that proves the inj is not at fault. If it were the inj, the problem would move.
Sorry you're having this much difficulty..
Is there ANY chance there is an OLD o-ring in these holes that are leaking? You;ve gone thru each hole with a PIC and made sure nothing is in there?
How many o-ring sets have you gone thru? all the same type?
I guess you have placed O-rings on each inj top and bottom to check the fit...they should slip on with some drag but not much. The ring compresses in the manifold to grip the inj and create the seal.
Did you move the inj around to different holes>??? random placement each time I hope?
if the same holes keep leaking, that would mean the HOLE is the problem, not the inj or the seal.
There ARE such things as "square" O-rings. Search the ph book or google to find a seal shop in your area that might have some. Mic the holes and take an inj and they will fit the o-ring to the application..
One more stupid question....you say #6 leaks every time, you are positive that its the inj leaking and NOT one of the rail joints or the regulator?
I have never heard of this much trouble getting a seal in the exact same hole, this many times after this many attempts....somethings AFU.
The reason I ask if the inj are being installed at random is to be sure the problem is not with a certain 1 or 2 inj, if you are putting a different inj in #6 each time,. that proves the inj is not at fault. If it were the inj, the problem would move.
Sorry you're having this much difficulty..
Is there ANY chance there is an OLD o-ring in these holes that are leaking? You;ve gone thru each hole with a PIC and made sure nothing is in there?
09-01-2013, 11:32 PM
#11
Race Director
Thread Starter
This last time around I ordered O rings from Jon at FIC. They are Viton and are black. I messed up and did not order enough of them so I placed an order for some more. These were blue. I flipped the fuel rail upside down, blew them out with compressed air and used alcohol wipes to clean them thoroughly. I then put 3 of the O rings that I got from Jon on each injector, lubed them with a gob of Vaseline and my helper and I followed your instructions to a T. Still had a leak at #6 after torqueing the fuel rail bolts to the proper ft lbs. Then after the leak I pulled only the #6 and #8 to check and see if the O rings were cut or folded over. Used a jewelers loupe and found no problems in the wells or with the O rings. The injectors were in tight and required quite a bit of effort to remove them. We then installed one new blue Viton ring on each of these injectors and reinstalled using dish soap. Now both leak.
Tomorrow I am going to pull the back 2 injectors and swap them with the front 2. If the leak persists on the back 2 I will know that the rail "wells" themselves are bad. If the front 2 leak then I will know that the injectors themselves are bad.
So, I will either be calling Jon for help on Tuesday or Vette2Vette to order a used passenger side rail. The leak is not traveling from anywhere else as we have paper towels under everything in the area in order to check for that problem.
I WILL get this tracked down.
Thanks for all the help
Tomorrow I am going to pull the back 2 injectors and swap them with the front 2. If the leak persists on the back 2 I will know that the rail "wells" themselves are bad. If the front 2 leak then I will know that the injectors themselves are bad.
So, I will either be calling Jon for help on Tuesday or Vette2Vette to order a used passenger side rail. The leak is not traveling from anywhere else as we have paper towels under everything in the area in order to check for that problem.
I WILL get this tracked down.
Thanks for all the help
09-02-2013, 08:29 AM
#12
Burning Brakes
I've had some difficulty before with fuel rails, especially with a super ram.
Since the holes in the intake are beveled, I believe that there is less of a chance to score/nick/twist/distort an oring by putting them in the fuel rail first, then into the intake.
I have always done it as all one piece, and actually slid the injector down into the intake while I was tightening the fuel rail bolts. Lube is essential, Vaseline or dish soap, and I have gotten lucky this way a few times now.
If the injector is sitting too high or too low in the fuel rail, it will leak. There is definitely a sweet spot that you need to find.
A lot of this has already been said but best of luck with the install.
Mike
Since the holes in the intake are beveled, I believe that there is less of a chance to score/nick/twist/distort an oring by putting them in the fuel rail first, then into the intake.
I have always done it as all one piece, and actually slid the injector down into the intake while I was tightening the fuel rail bolts. Lube is essential, Vaseline or dish soap, and I have gotten lucky this way a few times now.
If the injector is sitting too high or too low in the fuel rail, it will leak. There is definitely a sweet spot that you need to find.
A lot of this has already been said but best of luck with the install.
Mike
09-02-2013, 09:46 AM
#13
Safety Car
Just curious, are you swapping the injectors around as you keep taking it on and off? Just wondering if by chance the injector itself may be defective, i.e. cracked, milled wrong or something. While your mic-ing the bores, mic the injector as well. Dunno, just a thought.
09-02-2013, 08:42 PM
#14
Race Director
Thread Starter
Swapped the injectors around and discovered that the 2 I have concerns with are leaking in their new spots.
I sent an e-mail to Jon at FIC requesting two new ones. This should solve my problem.
Once again - thanks for your help.
I sent an e-mail to Jon at FIC requesting two new ones. This should solve my problem.
Once again - thanks for your help.
09-03-2013, 05:51 PM
#15
[QUOTE=GKK;1584816376]Jon's instructions say, to install the injectors into the Intake Manifold First and then into the Fuel Rail.
Also, Jon recommends using Dish Soap instead of Petrolem lubricants to lube the O-Rings. Petroleum lubricants attract dirt and won't evaporate like dish soap will which is what you want.
I've followed Jon's instructions on Three separate Injector installs and have never had a single problem!...
I have done it that way and then I tried it MY way... and I found that it is MUCH easier to drop the rails, injectors hanging, to be able to SEE where they are going and be able to guide them into place. It is awkward trying to set the rails ON 8 injectors because you cannot SEE the holes they are going in...its a game of feely fondle the parts and I have better results when I can SEE the inj tip entering the seals and when I can position ALL 8 to go together instead of a few here or there and end up being uncertain. Try it sometime. Dropping the assy down and placing all 8 on the manifold IS easier.
Also, Jon recommends using Dish Soap instead of Petrolem lubricants to lube the O-Rings. Petroleum lubricants attract dirt and won't evaporate like dish soap will which is what you want.
I've followed Jon's instructions on Three separate Injector installs and have never had a single problem!...
I have done it that way and then I tried it MY way... and I found that it is MUCH easier to drop the rails, injectors hanging, to be able to SEE where they are going and be able to guide them into place. It is awkward trying to set the rails ON 8 injectors because you cannot SEE the holes they are going in...its a game of feely fondle the parts and I have better results when I can SEE the inj tip entering the seals and when I can position ALL 8 to go together instead of a few here or there and end up being uncertain. Try it sometime. Dropping the assy down and placing all 8 on the manifold IS easier.
09-19-2013, 07:55 PM
#17
In order to SEE I do it with inj hanging and I can SEE where they are going as they enter each hole. Since 90% of all o-ring leaks are at the top ring/seal due to that being where the pressure is,. that is the seal that I want to KNOW is correct and not being rolled when it can't be seen. Set the inj in the rail perfectly and the lower rings are easy...just guide them and "snap-set" the assy in place. Since there is no pressure under the inj, only vac there is less risk of leak/problems, car-b-que later.
Its the same principle as backing in when you park. You can see as you arrive, and your view is ahead as you leave later. There is less working blind. Less opportunity for mistakes/accident.
Last edited by leesvet; 09-19-2013 at 07:58 PM.