Fuel injector leaks

Torn Mind

Lifer
Nov 25, 2012
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I thought I was in the clear with a set of very expensive OEM Toyota injectors. I'm just almost instead of completely.

The outside of the fuel seat still shows signs of pissing fuel even though the injectors are brand new OEM. Even with this leaking injector, at least some improvement has occurred in the fuel trims compared to the garbage Ebay counterfeits I had installed a few months back.

Gonna have to check the rail to see if there are contaminants I didn't notice. The only other way there is gas coming is from the bottom up, with sounds ridiculous.
 

pcgeek11

Lifer
Jun 12, 2005
21,335
4,469
136
I thought I was in the clear with a set of very expensive OEM Toyota injectors. I'm just almost instead of completely.

The outside of the fuel seat still shows signs of pissing fuel even though the injectors are brand new OEM. Even with this leaking injector, at least some improvement has occurred in the fuel trims compared to the garbage Ebay counterfeits I had installed a few months back.

Gonna have to check the rail to see if there are contaminants I didn't notice. The only other way there is gas coming is from the bottom up, with sounds ridiculous.

Is the leak from the external o-rings (top or bottom) or leaking from the internals of the injector?

Did you also replace the o-rings with properly lubricated o-rings?

Were the seating surfaces for the fuel rail and the intake clean and free of debris?

Fuel Injectors rarely fail and when they do it is usually withing a few hundred miles or less. I was employed at a major worldwide automotive supplier of fuel injectors for 30 years. What it sounds like from your description is the external O-rings that are leaking. If so you don't need to replace the injector just the o-ring(s) and clean the o-ring seating surfaces.
 

Torn Mind

Lifer
Nov 25, 2012
11,678
2,657
136
Is the leak from the external o-rings (top or bottom) or leaking from the internals of the injector?

Did you also replace the o-rings with properly lubricated o-rings?

Were the seating surfaces for the fuel rail and the intake clean and free of debris?

Fuel Injectors rarely fail and when they do it is usually withing a few hundred miles or less. I was employed at a major worldwide automotive supplier of fuel injectors for 30 years. What it sounds like from your description is the external O-rings that are leaking. If so you don't need to replace the injector just the o-ring(s) and clean the o-ring seating surfaces.


It looks like it is from the top and only under load, because there is a small pool of gas and the smell of gas.
The injector feels dry on its body, so if it is spraying from the top, it's not touching the injector itself.
I replaced the injectors because the 27 year old OEM injectors were running like 27 years old injectors subjected to non-top tier gas. Tried a batch of Ebays, they proved a failure, and had leaks from two center injectors. So I got these brand new OEMs, and one center injector(seal) still is leaking.

I did notice three small specks in the leaking injector port. If the injector keeps leaking, the only thing left is to carefully clean it.

It's an I4 1ZZ-FE.
 

pcgeek11

Lifer
Jun 12, 2005
21,335
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What is the fuel pressure?
Good question. If the fuel regulator is stuck closed the pressure will be high. It still shouldn't leak however as by high I mean about 60 psi max where it should run about 40 ish psi.

Sounds like trash or dirty o-ring sealing surfaces top or bottom. Are you sure the rail is firmly seated on the injectors and the injectors are firmly seated into the intake?
 

Torn Mind

Lifer
Nov 25, 2012
11,678
2,657
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I'm not sure I can take measurements of the fuel pressure. It's unlikely that it will be too high, given it's the OEM fuel pump of almost 17 years.

It's really just odd that the injectors themselves seem dry on the exterior but there is clearly gas showing up on the exterior metal next to the injectors.
 

RLGL

Platinum Member
Jan 8, 2013
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If the fuel regulator is stuck closed the pressure will be high. It still shouldn't leak however as by high I mean about 60 psi max where it should run about 40 ish psi.
Oh yes it will, I have seen it.
 

pcgeek11

Lifer
Jun 12, 2005
21,335
4,469
136
With good o-rings and a proper seal it shouldn't leak at 60 psi...
Better?
 

pcgeek11

Lifer
Jun 12, 2005
21,335
4,469
136
In order to fix this you will
I'm not sure I can take measurements of the fuel pressure. It's unlikely that it will be too high, given it's the OEM fuel pump of almost 17 years.

It's really just odd that the injectors themselves seem dry on the exterior but there is clearly gas showing up on the exterior metal next to the injectors.
Are you leaking on one injector or more than one? This post seems to indicate more than one leaking.

In order to repair this you will need to locate the exact source of the leak.
Common locations for leakage are the Top (fuel rail) or Bottom (intake) O-rings.

On rare occasions there have been weld seam leaks on the fuel injector themselves, but this is very rare. If that were the case the fuel would be coming from inside the molded body.

Maybe swap the injectors around to different positions to see if the leak moves with the injector or stays on the same position. Quick and easy check. If it moves it is the injector if it stays with the position it is something with that position, seating surface or even a leak on the fuel rail itself...