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302stephen
03-13-2021, 12:45 AM
Hi everyone,

I was hoping to get some input on an issue I've been having with my 2014 S4. A little while back my water pump started leaking so I decided to do that and all the related maintenance. I replaced the water pump, thermostat, PCV, and did a carbon cleaning. I also replaced various gaskets and O-rings that I removed including the fuel injector O-rings. I soaked the injectors that came out with the intake runners/fuel rail in injector cleaner as they where looking dirty but didn't have the proper tool to remove the others from the heads so I let them be.

After putting everything back together and driving about 800 miles or so I started to smell a strong fuel smell while driving. I looked around under the hood and determined the fuel leak was coming from under the supercharger. I took the supercharger back off and pulled off the intake runners and saw that I forgot to remove some of the old fuel injector O-rings and one of the new ones had been damaged. I didn't have any spare O-rings on hand so I had to reuse one of the old ones that looked to be in good condition.

After putting everything back together again I drove around a little and got a CEL, after looking at the codes I realized that I didn't push the flaps in the intake runners down as I was installing them so they where stuck closed. I pulled everything apart again and lifted the intake runners just enough to push the flaps down and get everything set again. I put everything back together again and the next day started smelling fuel again.

I ordered more of the fuel injector O-rings and tore everything apart again and found another damaged injector O-ring. I replaced it and put everything back together again today but after leaving my car sitting for a couple hours it took a couple extra seconds longer than it normally does turning over to start. It seems to still be lousing fuel pressure although it doesn't smell strongly of fuel yet. The first couple times it was leaking the leak would get worse and worse until the car would barley stay started at idle.

Some other info that may or may not be relevant:

I followed the instructions in FCP Euro's videos for doing everything.
I used URO fuel injector O-rings instead of OEM.
The car is a 2014 S4 DSG Prestige with about 72K miles.
The car is ECU and TCU tuned with IE stage 1, has an IE intake and ECS tuning exhaust.

Does anyone have any ideas on what I can do? I'm getting way better at taking the supercharger off than I ever wanted to be and at this point I just need it to run. I would really appreciate another perspective on this; the only other things I can think to do is replace the injector O-rings again with OEM O-rings, replace the injectors all together, or take it to a shop and hope they can fix it. Those options can get pretty expensive so I was hoping to get some outside perspective first. I know the chances are high that I'm just not doing something right when taking everything apart/putting it back together but I am at a loss as for what to do differently.

TLDR: Persistent fuel leak from around injectors after carbon cleaning even after replacing the Injector O-rings.

djn876
03-13-2021, 04:26 AM
How did you do the install of the orings? Did you use the tool to compress them after slipping them on to the injector?

Maybe get the Audi ones just to try something different?

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evanb
03-13-2021, 02:50 PM
You must be getting pretty good at pulling all that shit apart. [headbang]

6SpeedS4
03-13-2021, 03:18 PM
Maybe use a better lube. I used a product called superlube that was made specifically made for orings and I would go with OEM after having that many issues.

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prabkaler
03-13-2021, 06:17 PM
Is it possible that when you loosened the 17mm fitting on the fuel lines that the brass fitting on one of the rails got loose? This has happened to me many times on a bunch of different cars


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302stephen
03-14-2021, 05:22 AM
Thanks for the replies, I put almost 200 miles on the car today with no issues aside from taking a couple extra cranks to start after sitting overnight. I honestly can't remember if that's normal to take a bit longer to start after sitting for 8+ hours. For the moment I'll just keep an eye on it and wait for the fuel smell to inevitably return.

djn876 I just slipped the o-ring over the injector and put some engine oil on it, I didn't know there was a special tool. What kind of tool is it? The only thing I've ever heard of is the tool to remove the injector which I don't have.

6SpeedS4 did you use the SuperLube 56204?

Prabkaler I don't think that's the issue, the driver side fitting did come loose but I did tighten it back down and I tightened the fittings on the fuel line side pretty good on both sides, but I will double check them next time to be sure.

I guess my plan moving forward is will be to get some SuperLube and bite the bullet and get a set of OEM o-rings and try those. And maybe a shop manual to see if there is some trick I'm just missing. I appreciate the help and will probably be back before to long.

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djn876
03-14-2021, 07:25 AM
Thanks for the replies, I put almost 200 miles on the car today with no issues aside from taking a couple extra cranks to start after sitting overnight. I honestly can't remember if that's normal to take a bit longer to start after sitting for 8+ hours. For the moment I'll just keep an eye on it and wait for the fuel smell to inevitably return.

djn876 I just slipped the o-ring over the injector and put some engine oil on it, I didn't know there was a special tool. What kind of tool is it? The only thing I've ever heard of is the tool to remove the injector which I don't have.

6SpeedS4 did you use the SuperLube 56204?

Prabkaler I don't think that's the issue, the driver side fitting did come loose but I did tighten it back down and I tightened the fittings on the fuel line side pretty good on both sides, but I will double check them next time to be sure.

I guess my plan moving forward is will be to get some SuperLube and bite the bullet and get a set of OEM o-rings and try those. And maybe a shop manual to see if there is some trick I'm just missing. I appreciate the help and will probably be back before to long.

Sent from my IN2025 using Audizine Forum mobile app (http://r.tapatalk.com/byo?rid=87676)This wouldn't be the viton o rings that seal against the fuel rail, these would be the Teflon ones that sit on the shaft of the injector, I'm probably mixing the two up right now since the one on the injector shaft isn't sealing against fuel pressure. That's my bad.

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302stephen
03-14-2021, 05:55 PM
This wouldn't be the viton o rings that seal against the fuel rail, these would be the Teflon ones that sit on the shaft of the injector, I'm probably mixing the two up right now since the one on the injector shaft isn't sealing against fuel pressure. That's my bad.

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I did replace the hard plastic ring below the rubber o-ring, I just sort of rotated it on to the injector. Could that be the problem? I didn't have any problems with those so I assumed they where ok. Is there a proper method for installing them on the injectors?

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prabkaler
03-14-2021, 06:17 PM
I did replace the hard plastic ring below the rubber o-ring, I just sort of rotated it on to the injector. Could that be the problem? I didn't have any problems with those so I assumed they where ok. Is there a proper method for installing them on the injectors?

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So there’s the rubber ones, the plastic one, and the Teflon one is on the actual shaft of the injector and a tool is needed to remove and reinstall it


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