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Where do "leaky" injectors leak from?

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Old 02-24-05, 09:49 PM
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Where do "leaky" injectors leak from?

Hopefully this question isnt too stupid. In the process of trying to get my barely modified/gross pollutin Ca car smogged I noticed the familiar scent of fuel under the hood. Took the car home and dug into the rats nest and it appears the fuel was coming from the top area of one of the injectors and dripping into the "pool" areas. (no I didnt pass smog on any level)
My injectors are 164k+ miles old and have survived a fire so yes its time for them to go. Once I started to examine the injectors and primary fuel rail I just couldnt fathom how fuel could make it way out (assuming I had every nut and bolt tght to begin with) So maybe someone who knows injectors better than I can tell me. Thanks
Old 02-24-05, 09:58 PM
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The injectors wouldn't leak out there. Don't drive the car. You need a new Fuel Pulsation Damper. Replace that before you drive the car again before you car burns down like a lot of other people's FDs.
Old 02-25-05, 02:29 AM
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Originally Posted by iluvmy3rdgen
The injectors wouldn't leak out there. Don't drive the car. You need a new Fuel Pulsation Damper. Replace that before you drive the car again before you car burns down like a lot of other people's FDs.
Not true..........

Your injectors have two "O" rings inside the fuel rails. if the top "O" ring fails (or is brittle over time) it would allow fuel, under pressure, to leak from the top. I would send your injectors to RC for cleaning & flow test. They return them with new "O" rings.

Over time the Pulsation damper has been known to leak. With the mileage you quoted I would also change that.

There is a TSB to replace the replace the rubber fuel hose that connect to & from the fuel rails. Again, with the miles on your car, I would replace those as well.

Your in for a treat. Those injectors can (and are) a bitch to access & remove without destroying them.

Good luck.

If you have a local shop clean & test your injectors I would highly reccomend buying the "O" rings from the dealer. Pucker up & pay the big bucks.

I had the local injector shop try to "match" up my "O" rings & they leaked like a bitch. I ended up trearing everything apart 3 times (thinking that I cut a "O" ring during install). After the 2nd time (with similar results) I ordered the OEM "O" rings & everything was tight.
Old 02-25-05, 05:36 AM
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What Sled Driver said about the injectors is right.
Injectors work like this:
- Fuel runs through the fuel lines at pressure, the fuel lines go in and out of the fuel rails, which are just short pipes that lead the fuel across the injectors.
- The injectors are just like doors: they open to allow some of this fuel to go into the intake according to the ECU signal.
- The injector sits in a hole that crosses the hole the fuel flows through. To seal this, there is an o-ring above and below the fuel flow between the injector and the fuel rail. A leaky o-ring will leak fuel. The fit and function of these o-rings is critical - there is certainly no 'Home Depot' option here.

The Fuel Pulsation Damper is another candidate. It's at the end of the fuel line, under the same pressure, and can also leak.

It could be either one, but with the history I suggest you pony up for all new stuff. You'll basically be doing a full rats nest job to get in there, see my writeup at www.davidgeesaman.com for a few pics. The FPD and Injectors are basically equally hard to get to, so I suggest servicing both. Don't forget the upgraded fuel lines.

Dave
Old 02-25-05, 09:10 AM
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You can also go with new injectors - this solves a world of problems . It's also not uncommon for the injectors to physically crack and leak - in that case you definitely need new injectors.

There was a thread on this not too long ago - Blitz sells 550cc side feed injectors that are IDENTICAL to the stock injectors - same numbers on them, everything. They just get them from Nippondenso, who makes them for Mazda. Anyhow, they're like $133 each brand new, which is quite a bit cheaper than Mazda. They also have 850cc side feeds, but I don't know if those will work or not for the secondaries.

But, I would start with the O-rings first - that sounds like it's the culprit.

Dale
Old 02-25-05, 10:20 AM
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One of my Primaries leaked when I got my car. It leaked out of the top, where the plastic on the top met the metal of the injector (no better way to describe it). If I had a pic I could show you where it leaked at, but if you look at one, you should see what Im talking about. I had to replace it, no way to fix.
Old 02-25-05, 10:22 AM
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leaky injectors come from mexico. and china.
Old 03-09-05, 12:07 AM
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I replaced my injectors with the Blitz ones and so far so good. My FPD is fairly new so I knew that wasnt the problem (it wasnt even wet when I took out the problematic primaries) My car also has had its original rubber fuel lines replaced. Since I have fresh (bendable) silicone vac hoses manipulating the rats nest didnt feel like I was defusing a bomb. Car is back to smooth as silk w/no leaks (@164,601miles and counting), thanks everyone
Old 03-09-05, 01:26 AM
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Originally Posted by DaleClark
You can also go with new injectors - this solves a world of problems . It's also not uncommon for the injectors to physically crack and leak - in that case you definitely need new injectors.

There was a thread on this not too long ago - Blitz sells 550cc side feed injectors that are IDENTICAL to the stock injectors - same numbers on them, everything. They just get them from Nippondenso, who makes them for Mazda. Anyhow, they're like $133 each brand new, which is quite a bit cheaper than Mazda. They also have 850cc side feeds, but I don't know if those will work or not for the secondaries.

But, I would start with the O-rings first - that sounds like it's the culprit.

Dale
Like Dale said. Primaries are prone to leakage, go for new injectors and be done with it. I've replace 3 sets of primary injectors that were leaking on FDs.
Old 03-09-05, 02:12 PM
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Car is back to smooth as silk w/no leaks (@164,601miles and counting), thanks everyone
How many engines?
Old 03-09-05, 09:03 PM
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just one. However, all rubber and fuel/emissions equipment have been replaced
Old 03-09-05, 11:06 PM
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Originally Posted by Sled Driver

If you have a local shop clean & test your injectors I would highly reccomend buying the "O" rings from the dealer. Pucker up & pay the big bucks.

I had the local injector shop try to "match" up my "O" rings & they leaked like a bitch. I ended up trearing everything apart 3 times (thinking that I cut a "O" ring during install). After the 2nd time (with similar results) I ordered the OEM "O" rings & everything was tight.
Or find an injector shop that has and uses the correct o-rings. I do admit, that the RX7 o-rings are difficult to get and our normal suppliers don't have them.

Gordon
WitchHunter Performance
Fuel Injector cleaning & flow testing service
Old 03-10-05, 06:31 AM
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Originally Posted by 150kFd
just one. However, all rubber and fuel/emissions equipment have been replaced
So you have an original engine with close to 165k miles? wow, how did you manage this?

my guess... no mods except for some reliability ones?

Please give us the secret of eternal life!!!
Old 03-10-05, 08:11 AM
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Originally Posted by turbojeff
Like Dale said. Primaries are prone to leakage, go for new injectors and be done with it. I've replace 3 sets of primary injectors that were leaking on FDs.
So is it better to just buy new injectors instead of sending them out to RC? Im in the process of taking them out and was thinking of getting all four cleaned, won't RC tell me if an injector is worth cleaning?
Old 03-10-05, 08:19 AM
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Question Fuel leak

I have noticed that if I do not drive my FD for two or three days that there is a small pool of fuel underneath it. What would cause this since here is no leak when it is driven.
Old 03-10-05, 08:43 AM
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So why are you driving it?

For gods sake, don't start the car again until you get a positive solution.

Dave
Old 03-10-05, 11:04 PM
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My car was an auto for 100k miles so the secondaries didnt see much action and boost levels were usually pretty low. Radiator upgraded, AC/PS tossed and dp hf cat and catback put in along with 5spd. Low boost levels and heat management has been the key.
If there is a leak of fuel I've learned to dig into the rats nest right away. If you have a garage and tools nothing should keep from inspecting your fuel parts. By all means dont drive it with puddles of fuel there.
For me injectors with 164k on them were not worth keeping. With tax and shipping, the Blitz 550s cost 285 for a pair.
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