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Lower injector seals?

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mazda-man

10+ Year Contributor
117
2
Jul 14, 2010
Street, Maryland
I have found during my boost leak test that all of my lower injector seals are leaking badly along with my fuel pressure regulator. I know you can get viton seals for fic injectors but they want work on the stock injectors. Is there a upgraded seal for the stock style injectors. I checked a couple of places and haven't found any. If not I'll just get some from my local dealer. Thank for any input.
 
Save your money, i got a set of 4 total injector seals (beck arnley) for my 1g from rockauto.com for only $16 and change shipped to my door
 
Ya I saw that kit as well on there site and was figuring on ordering that to get everything I would need. Thanks for the input. Now I just have to replace my leaking fpr and then that should be it on boost leaks.
 
Ya I saw that kit as well on there site and was figuring on ordering that to get everything I would need. Thanks for the input. Now I just have to replace my leaking fpr and then that should be it on boost leaks.

The vacuum line is leaking? Just wrap a zip tie around it or replace the line if it's old an then secure it with a zip tie.
 
It's not actually your lower injector seals causing the problem unless they're hard as nails. It's really a tolerance issue. The fuel rail is held on with spacers to compensate for the thick portion of the body of the injectors. The upper seals work like a spring to press the injectors into the lower seals off of the bottom of the fuel rail. You can replace lower seals and still leak afterwards like I did if the upper seals are bad. I'm not talking about the o-rings that seat into the fuel rail. I'm referring to the rubber ones that fit down over the whole upper shaft on the injector.

There are various ways of modifying the upper seals to make the injectors press harder into the lower seals... but I found that a $4.99 assorted box of grommets from harbor freight has a set of 5/16" grommets in it that are a hair thicker and slightly less-pliable than the factory upper seals, but not thick enough to push the upper seal out of the rail. They work beautifully and I've boosted it to 40 PSI on the same leaky lower seals while boost leak testing, and not a single leak. They also cost 1/4 as much and you're left with 96 spare grommets for your next 50 wiring jobs.

Have that little nugget.

EDIT: OH... hey... yeah that bit about your fuel pressure regulator... Is it leaking gas into your intake manifold? Pull the vacuum line after it's been running and see if fuel dumps out. That could be really bad.
 
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