2G Leaking boost in middle of FIC injector??

[ScrubyMcBubble]

Hello everyone! I need your guidance and opinions. Swear ive googled to the moon an back on this one and found nothing here or there.

I'm boost testing my 95 GST and found that my FIC 1200 Hi-Z's are leaking in the middle. Not on the seats or the fuel rail but right in the middle close to where the wires connect. Short videos attached for the TL;DR

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To explain further i start by turning the key for the fuel pump to kick in and pressurize the rail, pinch the vacuum line for the MBPR, pump 20 - 25 psi of pressure from my air compressor into the turbo inlet. Spray everything down with soapy water and found no notable leaks except for bubbles from all 4 of my injectors in similar places, and also from the OEM Fuel pressure regulator.

When supplying FIC with the videos they were very quick to send me another set under warranty (Awesome support from this vendor!). After installing the new set they have near identical symptoms however the leaks are slower and more subtle. The previous owner has stated it has a walbro 255 fuel pump (certainly whines like one) but it only has the OEM Fuel pressure regulator so im thinking my next steps should be to get a FuelLab or Aeromotive AFPR and new lines.

Something about this still doesnt seem right to me and i still can't explain why i have these symptoms. If air can leak from the injectors, would fuel not leak from them too (especially at 43.5psi)?? Could this be caused from a failed diaphragm in the oem FPR?

More car context: It came tuned on a piggyback SAFCII with 550's, i have since swapped for 1200 FIC Hi-Z's with ECMlink and added a fresh wideband. I went as far as tuning idle on speed density before taking a step back to make sure there wasn't anything missing that could cause me to have to tune it all over again.. So im looking at the basics first before proceeding with anymore tuning. I saw no signs of fuel leaks and smell no gas when i was tuning idle.

Only had this one for 2 years so its a work in progress.

 

[donniekak]

Ya, but how would it be making bubbles at the lip of the upper adapter cup?

If instead of the o ring leaking, it could be the injector body itself.

I would pull the adapters off and have a look.

 

[ScrubyMcBubble]

Got the new Fuel system fully installed. -6AN from the sending unit to a new fuelab filter, -6AN from filter to a new FIC rail, -6AN from rail to new fuelab AFPR then to the oem return line (for now).

Returned to testing the boost leak on the injectors now that they are sitting under a new Fuel rail. On first look last night I'm only seeing one leaking boost. I notice the height adjuster have a bit of wiggle to them but doesn't seem to have any change on the leak however I move it. If I move the injector enough it will leak boost from the seat too. This Fuel rail can seat with uneven pressure as the two screws on each leg have lots of play until tight. I'll try adjusting the fuel rail tighter on the other side tonight to see if it improves this any.

I'm planning to individually leak test some of the other injectors with the height adjuster removed so I can verify if it's leaking through the body or around it. I'll be back with footage of that later this weekend.

 

[ScrubyMcBubble]

Here's a video of the latest test last night.

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[steve]

This really looks like an issue for FIC to resolve at this point.

 

[ScrubyMcBubble]

This really looks like an issue for FIC to resolve at this point.

Yeah, they had sent me a replacement set which is what is on the car right now. I haven't sent in the other set yet so maybe I'll just pick the best 4 and send back the worst 4.

 

[chrisman287]

Yeah, they had sent me a replacement set which is what is on the car right now. I haven't sent in the other set yet so maybe I'll just pick the best 4 and send back the worst 4.

Definitely what I would do. Or just return all 8, get a refund and go with another brand.

 

[Justin DuBois]

Ah, what a bummer - I just know you will feel better with a change out here - unless they got like next day air customer support.

 

[ScrubyMcBubble]

Alright, I did some tests on the original 4 I had (not the warranty replacements in the car currently). Tested these outside of the car and CAN CONFIRM the leak is not through the body of the injector but rather through the plastic seam between the body and the exterior. Skip near the end of the video to see this confirmed when I take the height adjuster off of the injector and test for leaks.

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I was able to confirm one of my old injectors was leak free so I'll swap that with the new one that was leaking bad in the car.. while I'm at it I'll test the other 3 outside of the car to see if I can manage to get 4 usable injectors or if I need to request warranty round 2. To their credit the shipping was very fast the first time.

 

[ScrubyMcBubble]

After testing the set of replacement injectors on the car they were also leaking but not as badly (except one). I reinstalled them replacing the one that leaked the most with the one that didn't leak from the original 4.

I think I'll just run with them as they are. The boost leak is very minimal with these ones and there is no fuel leak. I'm sure the boost leak could cause these to fail faster than expected but they are lifetime warranty so I'll just deal with that when it comes.

Since the 4g63t is port injection the intake valves would protect the injectors from any combustion passing through the same boost leak point except in the case of knock or premature detonation. The engine is always going to vacuum fuel and air from the port as the valves open so it's unlikely for fuel to be forced through the same leak as the injector opens. The only situations I see that could cause issue is backfire and predetonation which if happening there is bigger concerns.

Thoughts?

 

[Justin DuBois]

After testing the set of replacement injectors on the car they were also leaking but not as badly (except one). I reinstalled them replacing the one that leaked the most with the one that didn't leak from the original 4.

I think I'll just run with them as they are. The boost leak is very minimal with these ones and there is no fuel leak. I'm sure the boost leak could cause these to fail faster than expected but they are lifetime warranty so I'll just deal with that when it comes.

Since the 4g63t is port injection the intake valves would protect the injectors from any combustion passing through the same boost leak point except in the case of knock or premature detonation. The engine is always going to vacuum fuel and air from the port as the valves open so it's unlikely for fuel to be forced through the same leak as the injector opens. The only situations I see that could cause issue is backfire and predetonation which if happening there is bigger concerns.

Thoughts?

There is a non-zero chance that a small amount of boosted air/fuel will leak out under operating conditions. The amount I’m talking about is the amount you are seeing in the soapy bubbles, and the condition this would occur is when the turbo is making boost in the intake manifold, regardless of RPM.

It seems like a small amount, and not at all the same kind of risk as if you had a fuel leak before the injector valve.

I would not buy these injectors myself given the issues you have found, but I’ve got a working car.

When you are looking to get up and running with a list of other issues to address, the desire to say “good enough” and move on is strong.

If I were you, I would move on to the next most important thing, cause injectors are a very easy part to access and swap out later.