Fuel rail seals

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Threshld1
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Fuel rail seals

Post by Threshld1 »

Wondering if anyone has any thoughts on a vac leak at the fuel rail? Is it possible to have an under boost only vac leak where the injectors seat into the manifold? I get a train style chugging sound from my drivers side whenever im above 5psi but its random that it will come and go and i cant find a source. It kind of sounds like an exhaust leak but ive replaced all the gaskets.
93 SS 5MT - TD05H-16G, 06 TMIC, Walbro, Zeitronix WB-02 - Scrapped too much rust
91 SS AT
97 Outback - Prodrive quick rack, DMS 40
Threshld1
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Post by Threshld1 »

Is this a feasible problem? Has anyone heard of anything like this or am i just making up overly complicated problems that doesnt exist.
Kent
93 SS 5MT - TD05H-16G, 06 TMIC, Walbro, Zeitronix WB-02 - Scrapped too much rust
91 SS AT
97 Outback - Prodrive quick rack, DMS 40
free5ty1e
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Post by free5ty1e »

I'd have thought that any leak involving the fuel system would spray fuel -- I believe all the way up to the rails, the fuel system is pressurized. No vaccuum. So I think you'd notice if this was happening. (poof!)
-Chris
91SS 4EAT stock, 200k mi
91SS 5MT rebuilt engine waiting for a shell
93TW 4EAT, Forester lift, 3" TBE, 11psi, 200k mi
94SS 5MT4.11+rLSD 311k km: RobTune550,TD05-16g @ 18psi,FMIC,3"TBE,Forester lift
Threshld1
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Post by Threshld1 »

I mean a vac (pressure leak) between the rails and the intake mani itself. not the 30-40psi fuel rail that would spray everywhere (had a leak at the fuel filter when i bought the car :shock:) .
My intake mani/intercooler stinks of fuel. A faint hint of fuel smell is noticable in the cabin only when im experiencing the chugging for an extended period (high load on the motor at <3k rpm while building boost)
93 SS 5MT - TD05H-16G, 06 TMIC, Walbro, Zeitronix WB-02 - Scrapped too much rust
91 SS AT
97 Outback - Prodrive quick rack, DMS 40
entirelyturbo
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Post by entirelyturbo »

The only seal between the fuel injectors and the intake manifold are the O-rings. And if there was a leak there, the fuel pressure at 40-50 psi or whatever it is would would leak out and make a huge mess long before any boost leak would occur.

You sure all your FMIC connections are good? I must confess, I haven't dealt with turbos on my own time, but when I see guys do custom IC installs and they have boost leaks, they can usually be found in the install work somewhere.

If you have fuel stink, the first thing you should check is the charcoal canister and its associated vacuum lines. The charcoal canister is the black thing that sits right behind your passenger headlight. It collects gas fumes from the tank, so if there were a problem with the canister or a ruptured vacuum line, you'd have escaping gas fumes and you would smell them quite easily.
"Der Wahnsinn ist nur eine schmale Brücke/die Ufer sind Vernunft und Trieb"

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Threshld1
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Posts: 529
Joined: Mon Dec 26, 2005 12:53 am
Location: Artic Tundra - MN
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Post by Threshld1 »

Ill check the canister. I put an N/A can in because my secondary purge valve got broken.

Im talking about the black seals in this picture which are independent of the 2 o-rings that go around the top and bottom of the injector inside the rail.
93 SS 5MT - TD05H-16G, 06 TMIC, Walbro, Zeitronix WB-02 - Scrapped too much rust
91 SS AT
97 Outback - Prodrive quick rack, DMS 40
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