Leaking Injector Seals

[nesquil]

Hello,
To begin, I bought my 2001.5 S4 about three months ago. It had a fuel smell in the cab when I bought it. I removed the fuel pump and put aviation gasket sealant on the fuel pump gasket. This fixed most of the gas smells.

The fuel smell came back. I then noticed the colored injector tops were looking wet after I smelt fuel in then cabin. So, I bought the injector seals from ECS Tuning, and I installrd them.
I used 0w-40 Mobil 1 oil when installing into fuel rail, but did not reapply when installing into head. When I fired her up I had one bad leak, kind of spraying like a little fountain. 5 of 6 were leaking.
Dissapointed, I tore her all back apart and checked the seals between the one good injector and a leaking one. They both felt real tight in the rail, took effort to pull out.
I put it back together yesterday, this time using a good film of vaseline when putting injectors back into rail then reapplied when pushing the fuel rail into the manifold. I used the injector clips. When pushing the whole fuel rail in, I felt the injectors slide into the head, which was a better feeling than the first time. I pushed down hard over all injectors with my hand and also with a ratchet extension. The fuel rail was as far down as it could go, the brackets for the four allen bolts was right plumb with the intake manifold. I started it up this morning hoping to take it on a 100 mile trip to the nearest city. Two injectors were spraying fuel. The others appeared to be not leaking; however, I pulled the rail off again and the colors tops all appeared wet.

Why the hell are these leaking? The new orings from ecs feel tight enough, better than the ones I bought from napa.

Should I redo this with the napa orings? They feel more loose.

I have Aviation Seal a Gasket stuff, should I use it instead of vaseline this time when installing the injectors?

I have had to lift the injectors up a little to grt the injector clips on. Would it be better to leave them off as they can deat deeper into the rail? And if I do forego the clips, would it be better to install the injectors into the manifold first, to be sure they are seated correctly? I felt them slide into place last time but when I pulled it off, it took a lot less force than the first time I pulled off the rail.

I really want to drive my car. This couple hour project has turned into a week and I feel like I wont be able to fix it myself anymore. There is no Audi dealership near me to get different orings.

[Daveb5s4]

I also had a fuel leak at the injectors. Thought it was the seals but turn out to be the bodies of the injectors leaking. Ended up changing the whole set.


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[LJS]

Are these OE injectors or are they an aftermarket item for increased fueling needs???
How's the condition of the caps in the fuel rail--are they round????
PS- the "Aviation Seal a Gasket stuff" you mentioned---Is that the dark brown goo, with an interesting aroma, in the small white bottle with the blue printing.....If yes DONOT apply to the o-rings--that stuff will harden and make servicing the fuel rail a major pain in the butt as it will need to be totally removed to ensure a proper o-ring seal if you remove the injectors at a later date...
I've heard of leaks at the head side with aftermarket injectors due to a dimensional difference between them and an OE part....Sorry that I can't provide an absolute answer....As far as assembly goes---you're doing it correctly.....Injectors to fuel rail, install clips...set assembly into head....The o-ring is a radial seal so setting them deeper into a properly sized bore will not buy you anything....

[rguil]

I would say get a set of genuine actual injector o rings from the dealership. I have also had issues with leaky oem injectors and ev14 injectors on the OEM fuel rail and aftermarket fuel rails. My brother and I have noticed that most injector o rings are sold to "spec" but in reality they are not fat enough to ensure a proper seal.
Tip of the day, once it stops leaking dont touch it!!

[KSEADUB]

I haven't ever used any sort of 'assistant' to install these things. Oil, vaseline, aviation gunk, whatever, shouldn't get anywhere near your fuel rail or injectors. They should seat onto the injector, and the injector to the rail with just firm force.


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[S4James]

silicone based grease applied in a very thin layer with your finger into the intake manifold is ok.

[2000s4_m]

As mentioned, get oem o-rings. Aftermarket o-rings have the same outer diameter but are not as thick as oem ones and some times they leak from the inside, injector to o-ring part


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[nesquil]

Okay, so I got it back together yesterday. It is now as good as before I replaced the old cracked seals. It leaks intermittenly from a few injectors.

I got best results lubing orings every time I tried seating the injectors. I put the injectors into the intake manifold, making sure to push squarly down with even pressure. If it rolled into the opening I pulled and reseated the injector. I was able to get the rail onto the caps fsirly easy, it didnt give any satisfying sliding down feels as I just pushed down in an x pattern getting every seated deeply. I didnt use the clips so I could see if it wasnt seated deep enough into the rail.

The bottom left one was visibly dripping from the fuel rail about a drop every couple of seconds, however, I pushed down on the fuel rail above that leaking injector and it stopped for a bit. Bad oring seal or leaky injector? Three of the injector caps look wet whenever I check with engine running, and I still get the fuel smell in cabin which can be strong to light. It doesnt seem to get worse with more load. At higher speeds the gas smell usually goes away. I have found it to be related to temperature if not random.

At this point I believe I should get new injectors. I saw the lowest left injector leaking from the top, unless somebody can tell me a good reason why I should have them sent to somewhere to be cleaned, refurbed, and flowtested. They are orange caps and car has 230k miles. They look to be original.
I would like to save money. Would larger injectors be a worthwhile upgrade for a stage 1 tune or save larger injectors for later?

So glad to have my car running again.
Other people with an s4, in first gear I seem to lose power at higher rpms, it pulls hard then starts to drop, like the higher rpms arent even worth getting into. Is this a boost leak or what? I boost leak tested but havent done another since replacing torn throttle boot body.

[nesquil]

silicone based grease applied in a very thin layer with your finger into the intake manifold is ok.

Went with petro jelly because it could possibly ruin the orings over time, but that's cheaper than dielectric grease getting burnt with fuel and ruining the o2 sensors.
Rather replace o rings than a driver side primary o2 sensor. I bougt these from ecs tuning. I will check if they are oe or oem.
Napa was too small on inside I changed all o rings that could spin easily on injector. The ecs tuning orings were tight enough to not spin.

[slowSfaux]

I have my set of used oe injectors that never leaked. If you're interested in swapping them with yours to determine if you have leaky injectors or it's just the fuel rail, pm me. $20 shipped

[nesquil]

I haven't ever used any sort of 'assistant' to install these things. Oil, vaseline, aviation gunk, whatever, shouldn't get anywhere near your fuel rail or injectors. They should seat onto the injector, and the injector to the rail with just firm force.


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That would take a lot of force for me. Intakr manifold not that clean, applying vaseline to it helped a ton and cleaned it a little. I also used brake cleaner on qtip to clean out the intake manifold holes before the thin vaseline application.

[nesquil]

Are these OE injectors or are they an aftermarket item for increased fueling needs???
How's the condition of the caps in the fuel rail--are they round????
PS- the "Aviation Seal a Gasket stuff" you mentioned---Is that the dark brown goo, with an interesting aroma, in the small white bottle with the blue printing.....If yes DONOT apply to the o-rings--that stuff will harden and make servicing the fuel rail a major pain in the butt as it will need to be totally removed to ensure a proper o-ring seal if you remove the injectors at a later date...
I've heard of leaks at the head side with aftermarket injectors due to a dimensional difference between them and an OE part....Sorry that I can't provide an absolute answer....As far as assembly goes---you're doing it correctly.....Injectors to fuel rail, install clips...set assembly into head....The o-ring is a radial seal so setting them deeper into a properly sized bore will not buy you anything....

OE Injectors from what I can tell. Orange caps. PO didnt include service records.
Thank you, that was what I needed to hear. I felt like I was maybe missing a step in the process. I believe watching the orings go in evenly and not wiggling or twisting the fuel injector when installing was important to fixing the heavy leaking I caused haha.

[KSEADUB]

That would take a lot of force for me. Intakr manifold not that clean, applying vaseline to it helped a ton and cleaned it a little. I also used brake cleaner on qtip to clean out the intake manifold holes before the thin vaseline application.

Interesting. Yeah, there isn't a positive 'click' at the fuel rail if i remember correctly. You just push the injector into the rail until you can properly seat the injector clip. Thats it.

Give some OEM seals a shot. They're pretty cheap if i remember correctly. Like 1.15 each or something. :)


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[Calif_Kid]

silicone based grease applied in a very thin layer with your finger into the intake manifold is ok.

Went with petro jelly because it could possibly ruin the orings over time, but that's cheaper than dielectric grease getting burnt with fuel and ruining the o2 sensors.

I've only replaced fuel injectors one time when switching between green top and green giant injectors, and when I installed the new injectors, I put a little bit of dishwashing soap / water on the O-rings to help them slide in place, but a small enough amount to not have to worry about much residue. The dishwashing soap/water is often enough to reduce the friction when installing things, but shouldn't/won't react with metal/rubber etc.- Jim

[nesquil]

Any recommendations for fuel injector refurbishing and flowtesting? I'm going to buy slowSfaux's injectors. Then I wouldnt have any down time replacing mine with his, then getting mine or his refurbished. I would like to get his injectors into my car, then I wouldnt be a driving fire hazard while I have my current injectors sent out and refurbished/flowtested. Can those fuel injector cleaning companies even fix a leaky injector or do they just diagnose it?

[nesquil]

I've only replaced fuel injectors one time when switching between green top and green giant injectors, and when I installed the new injectors, I put a little bit of dishwashing soap / water on the O-rings to help them slide in place, but a small enough amount to not have to worry about much residue. The dishwashing soap/water is often enough to reduce the friction when installing things, but shouldn't/won't react with metal/rubber etc.- Jim

Why'd you upgrade?

[Calif_Kid]

Why'd you upgrade?

The car was a 2001 S4 with an AWE stage 3 kit. The car would often backfire, and the reason that I heard was that the older injectors (green top or green giant - I forget which) didn't control / shut off the fuel very well, so I switched to the newer injectors, and that fixed the backfire. You don't hear about those older injectors very much vs the newer injectors like EV14. - Jim

[MacDaddy]

I had this happen a bunch of times... I beleive what causes the bodys to leak is people prying off the fuel rail with the injectors in place and the injectors fused into the manifold, i finally "fixed" it when a guy from the local club gave me an intake manifold and i removed the injectors myself and sprayed some wd-40 on the old seals so that minimal force was needed, and installed new injectors.

If your current injectors are hooped theres not a lot you can do that i know about.

[nesquil]

I had this happen a bunch of times... I beleive what causes the bodys to leak is people prying off the fuel rail with the injectors in place and the injectors fused into the manifold, i finally "fixed" it when a guy from the local club gave me an intake manifold and i removed the injectors myself and sprayed some wd-40 on the old seals so that minimal force was needed, and installed new injectors.

If your current injectors are hooped theres not a lot you can do that i know about.

Okay, so mine were a pita to remove from the intake manifold. Are you recommending I get ones that dont leak, like from slowSfaux?

[MacDaddy]

If they leak or not will depend on how they were removed... if slowsfaux removed them gently withiout reefing them out if the manifold you should be fine, otherwise its a shot in the dark, i was mixing and matching from 3 sets of different injectors untill i found a set that didnt leak.

[nesquil]

Car stuttered when starting this morning.

Checked seals.
Back two and bottom injectors not leaking.

Currently have rail pulled off.
Replacing the three leaking injectors fuel rail seals at the moment.
Installing with a thin film of vaseline.
Putting clips back on too as it appeared the injectors werent seated far enough into the fuel rail.

Here's pics of the seals:
B5 s4 injector orings https://imgur.com/gallery/CCEop

Really dont want to spend more money after buying timing belt parts and tools...

I want to go to a fair 100 miles away for my birthday today but I'm stuck doing this for a fourth time. 😧

[jtozier]

Anyone know the part number for the oem 2.7t allroad 2004 fuel injector orings? I used the bosch ones and am still getting leaks.

Car stuttered when starting this morning.

Checked seals.
Back two and bottom injectors not leaking.

Currently have rail pulled off.
Replacing the three leaking injectors fuel rail seals at the moment.
Installing with a thin film of vaseline.
Putting clips back on too as it appeared the injectors werent seated far enough into the fuel rail.

Here's pics of the seals:
B5 s4 injector orings https://imgur.com/gallery/CCEop

Really dont want to spend more money after buying timing belt parts and tools...

I want to go to a fair 100 miles away for my birthday today but I'm stuck doing this for a fourth time. 😧