Boost/vacuum leak at injector insulator/seal in head

[93TSI_370K]

Stock 93TSI FWD Auto, I mean stock (with some aftermarket repair items) with idle surge issues. I am trying to get that fixed finally. Background: With 370,000 miles on the original injectors, figured I’d send them out to get serviced by someone who has an ASNU injector cleaning machine. They checked and cleaned them, replaced the injector filter baskets and the pintle caps. I used new injector insulators for the pintle caps, new O-rings and new “grommet” on the fuel supply side of the injector. Torqued the fuel rail down to spec, 7-9 ft/lb, pressurized the intake through the TB about 5-10 PSI, sprayed soapy solution all around and at the base of the injectors and I am getting bubbles there where the injectors go into the head.

All the insulators/grommets/O-rings are new, so I should not have any bubbles.
Maybe the pintle caps that the injector service removed had a little thicker rim where the cap seats against the injector? And the ones that are now on it have a thinner rim which is making the injector “shorter” and not sealing completely against the insulator in the head?

I can rotate the injectors with one finger and not a lot of force when the fuel rail is fastened down. That is why I am thinking they are not being compressed enough by the fuel rail to seal properly. I was thinking of adding a thin O-ring under the “grommet” to essentially make the injector “longer” so that when I tighten down the fuel rail, it will take up any space that is causing the boost leak bubbles. Got to get this fixed first and maybe it will hold pressure or enough to allow me to check the rest of the intake manifold/TB shaft seals/FIAV and ISC.

Anyone see something that I did incorrect or see some flaw in my logic to fix the leak?
Thanks

 

[bryanwheat]

Do you have the spacers on top of the injectors installed? They go around the top of the injector and are pushed on by the rail.

 

[93TSI_370K]

I have all the parts that belong on the injector.....on the injector. Only four items, the O-ring, and the spacer (or grommet I call it as it does resemble one) on the top of the injector, the pintle cap and the spacer (insulator) on the bottom of the injector. The components are all there, all new.

 

[92AWDHX40]

check to make sure they are all lined up, and go from there.

 

[93TSI_370K]

Make sure they are "lined up"? Sorry I really do not understand what you are saying.

I installed the injectors with the new components and I had the car running fine (except for the nagging idle surge that lasted until it warms up to operating temperature). Then I decided to do a boost leak test and that is when I found they were leaking. So they are assembled correctly as the car ran, it did not leak fuel or cause a fire.

I'll post a picture of the components assembled to the injector sometime this weekend (if I can figure out how to do it as I am not real tech savy) so no one else will ask if I have everything assembled correctly......or it will show that I am a complete imbecile and can't assemble a simple four piece puzzle. My wife has a third option... but all wives have an opinion of their husbands.

 

[And_44]

On my last 2 dsm's I've replaced the o-rings on had same issue. So the last one I added an aditional o-ring between the grommet and injector seemed to have fixed the issues no leaks.

 

[93TSI_370K]

And_44, thanks for the information, I was beginning to think that I was doing something wrong because no one else was indicating they had a similar issue. I'll bet everyone is running bigger injectors and not stock anymore so they have not had this issue.

I figure that it I would also put an extra O-ring up on the fuel rail end and not down by the head as the temperature may be a little less and they would last longer.

Will try it this weekend and post back the results but as you did it sucessfully, I am 99.9999% sure it will solve the leaking issue. I never say 100% when working on the DSM as nothing is guaranteed to work it seems, always something a little different or numbers for an application are wrong.

Had to replace the starter last year after 18 years of the original starter working. Got a replacement from an auto parts store and it did not engage the ring gear, it just spun. ALL of the stores had the same vendor number listed for the AUTO trans but I had to figure out that they had the numbers for the auto and std trans switched. The people in the stores tested the replacement starters and they all worked, but what they did not think of, was that the snout of the starter for the auto needed to be longer to engage the ring gear on the converter because it is not as close to the crank as the flywheel on the std trans is. That drove me nuts for 2 days!

 

[And_44]

Yea, i believe the issue comes from the upper sleave on the fuel rail side of the injector shirnks some over time.

As for the install I'd recommend installing the rings on the lower part of the injector on the pintel. I'd prefer mine to be in the fuel rail as far as possible. You can use the rings made for fuel systems, viton???, they can withstand the temps.

I had a similar issue with my starter on my 300m. Found I had to rotate it as I installed it to get the teeth to engage. If I didn't they would rest against the teeth of the flywheel.

 

[1bad4g]

i've had this leak before. one reason was because i removed the lil tabs that hold the throttle cable was not on. the ones under the bolts that hold it down the rail..
the second reason was because the rail was over torqued...witch caused and out of flat fuel rail. pick up a new used rail from the salvage yard. and use some small washers to replace the throttle cable tabs.. i did this and have had zero problems

 

[93TSI_370K]

I put an O-ring under the grommet at the top of the injectors (the fuel rail side) and that fixed my leaking at the injectors. Boost leak test at 10-12 PSI held for almost a minute before dropping to 0. I could hear some air in the crankcase but I figure it is probably going past the rings.

Did a full system boost leak and found that there were some leaks in the diverter tube (the tube from the turbo diverter valve to the intake hose-or whatever that assembly is called that goes from the MAS/Air filter the the turbo) and also some leaks at the metal fitting that the diverter tube attaches to the intake hose assembly. I had thought I fixed those earlier as I put some RTV on those leaks but it did not adhere that well, so I removed the old RTV, wire brushed, cleaned with MEK and applied a better and wider bead of RTV and now I am waiting for it to cure. Found these items online for $64 and $38 dollars but will wait to see if the RTV held this time. As I have a complete stock turbo setup, I believe going OEM is my only option for these items unless I did not search enough to see if there were any hard lines that I could use.

I will make this post "resolved"(hopefully) as soon as I get it back running and see if the surge is gone. I believe that I got all the leaks because I sprayed down both sides of the throttle shaft and did not see any leaks there or on any of the other hoses. It was impossible to check for FIAV leaks as that is underneath everything, but I do have a FIAV gasket if I still have a surge issue as that is the only place where I could not spray with soap/water.

 

[tay97gst]

Hoping someone can answer my question because i don't wont to open a new thread. I just did a BLT after rebuilding my throttle body and luckily the TB doesnt leak anymore but now i have a leak out of 2 of the fuel injectors where the sensors are. When i push down on the sensors the leaks stop, what does this mean my problem is?

 

[bryanwheat]

Hoping someone can answer my question because i don't wont to open a new thread. I just did a BLT after rebuilding my throttle body and luckily the TB doesnt leak anymore but now i have a leak out of 2 of the fuel injectors where the sensors are. When i push down on the sensors the leaks stop, what does this mean my problem is?

What sensors are you talking about?

 

[tay97gst]

What sensors are you talking about?

I knew that would be said... um im referring to the tops of the fuel injectors i guess, where the wires are on the top. I guess that's just part of the fuel injectors. But when i push down on those the leak stops.

 

[mattasi]

I knew that would be said... um im referring to the tops of the fuel injectors i guess, where the wires are on the top. I guess that's just part of the fuel injectors. But when i push down on those the leak stops.

You need new fuel injector insulators. They are a very common spot for boost leaks.

While you are replacing those you might as well replace the o-rings as well here is a kit from jnztuning.com
http://www.jnztuning.com/product_in...=2356&osCsid=9e29a04b2851ba5d54f41c240bd58ce6

 

[tay97gst]

You need new fuel injector insulators. They are a very common spot for boost leaks.

While you are replacing those you might as well replace the o-rings as well here is a kit from jnztuning.com
FIC OEM Style Seal Kit : JNZ Tuning

Oh ok, i wasn't sure if thats what it was so thanks for clearing it up for me.