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Tips Needed: Fuel leak @ injectors

Ok, so I had my injectors out to clean and flow test which went well. I followed the instructions from these threads on how to clean:
Blocked Injectors - how to clean?
Backflushing CIS injectors

I did a flow test using multiple System pressure and Boost Control pressure settings. Here are my results.






So, now my question. I have sweating from the #3 & #6 injectors at the fuel line to injector connection. I have a leak on #2 same location.

I was very careful to seat the fitting before threading the fitting and tightening. I also used a bit of motor oil on the threads to help seal.

Looking for tips to fix my leaks please!!

Thanks.
Old 05-02-2014, 08:00 AM
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if the motor is in the car, they are a pain to tighten. make sure what ever you are using to tighten them is not hitting on the injector blocks.
i have had mine out several times inth epast year. i bought a short wrench from advance then ground down the outside edges so it would fit better.
#1 os the hardest for me.
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Old 05-02-2014, 08:05 AM
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Be careful not to over tighten as this can distort the ball and cause a leak. Any tension on the hard lines must be relieved as you tighten the nut in order for the ball to seat properly. It's not easy, especially on cylinder one.
Old 05-02-2014, 09:36 AM
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Great.. #1 is the one that worked perfect for me. #2 is my biggest concern.
Anyone with a magic trick to help??
Old 05-02-2014, 10:27 AM
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i use a 12mm on the injector, and a short ground down 17mm. you just gotta get in there and do it
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88 BMW 325is 200K+ SOLD
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
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Old 05-02-2014, 10:52 AM
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Hold the injector with 12mm open end and snug down the line with a 14mm open end. Not too tight and of course not too loose either.
Old 05-02-2014, 10:57 AM
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Still no luck on #2 & 3.
I have tried everything I can think of, loose, tight, with oil, ....
I can get it to seal with the system charged and then let it relax. After check this 4-5 times with maybe 30 min. apart and eventually they start to leak again. It always happens when the system is off and pressure starts to drop.
There has to be a better fitting to seal these injectors??
Old 05-05-2014, 04:47 AM
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that does not sound right. are you sure it is leaking where the lines attach to the injector.

make sure there is no "tension" on the line. tighten the line down then remove the end at the fuel head. see if the line wants to move away from the head.

if stil not go, pull the 2 lines and inspect the ends for defects
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08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
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Old 05-05-2014, 06:04 AM
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Thanks, I will try that next.
Old 05-05-2014, 06:13 AM
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I don't know but it sounds like they've been overtightened. Do they all leak?

I just did an injector flow test on mine into six 6 oz plastic water bottles and I only snugged the lines on for that and none of them leaked. I do tighten them a little more than snug when doing the final install so they don't come loose down the road from vibration and start a fire or something.

You could use a crows foot wrench on an inch pound torque wrench if the feeling for just snug is questionable for you.
There is a tightening torque spec for them somewhere.

BTW, mine sprayed real nice and filled the bottles evenly after gently wiring the pintle open and back flushing them with compressed air and carb cleaner after soaking them in a glass jar of techron for 3 weeks a month ago.

My motor has never idled as smooth and even as it does now. I was also really anal about getting the 964 cam timing exactly the same 1.26mm for the intake valve during TDC overlap on each side too and then remounting the dial gauge and checking it again afterwards.
Old 05-05-2014, 04:13 PM
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I have had that happen to me. The injectors were faulty. Had probably been over tightened as mentioned above. When I got new ones, just a snug fit was enough to seal.
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Old 05-05-2014, 05:51 PM
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When i took them off they were really tight!!
If they were over tightened, is it the injector that gets distorted or the fuel line?
Old 05-06-2014, 07:42 AM
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The injectors seem to be made of hard steel and I doubt the female inlet fitting on them gets distorted. I think it's the ends of the lines that gets distorted from over tightening them.
I've never looked at them under a microscope though so I don't know.
If you ask Chris at TurboKraft he could probably tell you.
Old 05-06-2014, 08:24 AM
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Bentley has tightening torque at 7.5Nm or 5.5 ft lb I think but that doesn't sound right. I dont see in factory manuals, not in technical specification guide, not in 101 projects and "how to rebuild and modify" says there were so many changes they didn't even bother to detail. Can anybody confirm the torque for this and your source for it?
Then I guess I need to get out the calculator when I add a crowfoot extension. Does everybody just guesstimate this stuff?
Old 05-06-2014, 04:57 PM
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Quote:
Originally Posted by reachme View Post
Bentley has tightening torque at 7.5Nm or 5.5 ft lb I think but that doesn't sound right. I dont see in factory manuals, not in technical specification guide, not in 101 projects and "how to rebuild and modify" says there were so many changes they didn't even bother to detail. Can anybody confirm the torque for this and your source for it?
Then I guess I need to get out the calculator when I add a crowfoot extension. Does everybody just guesstimate this stuff?
I don't use a torque wrench on any type of automotive or aero fuel or hydraulic lines (is far too much trouble for something so simple). That being said, I've been working with these for 25 plus years, and early on, I fuc@ed up a line or two!

The key to not over tightening fittings such as these is to use a proper line wrench and then after you have tightened to the point that all slack is gone (aka - "snug") you finish the process by basically holding the wrench with just your thumb and fingers (not the palm of your hand) as you turn it home. It is hard to over-torque something when a relatively small wrench is turned in this manner, but of course, the sense of "tightness" is still very subjective and hard to convey to someone with little experience with this. I basically tighten until the nut stops turning when using the "thumb/fingers only" method (sounds like something Paul does with himself ) while using a "reasonable amount of force" (subjective, of course). But again, it is difficult to put much force on anything when holding the wrench/ratchet with just your thumb/fingers. It might be a good idea to practice this technique on a similar sized nut-bolt combo if you want.

Last edited by Ronnie's.930; 05-06-2014 at 05:29 PM..
Old 05-06-2014, 05:12 PM
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The ball fitting on the end of the line is what distorts. If this has happened, and it sounds like it has, you must replace the line.
The word I use to describe the torque spec is "snug". If you give it any strength at all it will over tighten. I test them by running the pumps when finished then re-tightening the loose ones.
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Old 05-06-2014, 08:06 PM
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Thx guys.
I was very careful not to over-tighten and just did finger tight, then light pressure on a wrench until is bottoms out. I think these were over tightened by the previous installer because when i took them off they took a lot of force to undo.
Figures.... nothing is a easy as it sounds when dealing with 27yr. old parts.
Old 05-07-2014, 05:46 AM
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No, they're old cars at this point, and love to fight you on the simplest of tasks...

Yes, they should only require minimal torque to seal, just like all tapered seat fittings (other fuel lines, AN fittings, etc.)

We have lots of used 1986-94 fuel lines if you need replacements.

The fuel line has an end fitting similar to a tube nut & sleeve, and the sleeve is integral to the ball end fitting. The most common mistake we see is not getting the fuel line's nut fully over the shoulder of the sleeve, but cockeyed -- thus not applying even torque.

One option to consider is conical sealing washers:
http://www.summitracing.com/parts/ear-169103erl/overview/
These are also available in dead soft copper from many hydraulics shops.
Fancy version:
http://www.flaretite.com/flaretite.php
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Last edited by TurboKraft; 05-07-2014 at 09:07 AM.. Reason: addition
Old 05-07-2014, 09:07 AM
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Chris, your the Man!!. thank you.
Old 05-07-2014, 10:15 AM
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Well, that fixed it. My lines were a -4 AN.
Old 05-09-2014, 12:21 PM
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