Testing injector o-rings
10-02-2008, 01:44 AM
#1
Testing injector o-rings
I just had my fuel injectors clean and flow tested by Witch Hunter (http://www.witchhunter.com) I was very happy with the service, but after installing the injectors (with new o-rings) Im wondering if I can test them to make sure none leak, before putting the engine back in the car.
Heres my plan, but Im just wondering if this would be a definitive test. First hook the fuel rail up to the fuel lines and then turn the ignition key so the rail is pressurized. If no fuel leaks out, the o-rings are sealing properly right? This is of course assuming that leaving the injector wires disconnected, the injectors will remain closed?
Heres my plan, but Im just wondering if this would be a definitive test. First hook the fuel rail up to the fuel lines and then turn the ignition key so the rail is pressurized. If no fuel leaks out, the o-rings are sealing properly right? This is of course assuming that leaving the injector wires disconnected, the injectors will remain closed?
10-02-2008, 11:07 AM
#2
Yup.
just leave the fuel rail off the car and give it some pressure. you'll know pretty quick what's going on.
Feed each injector +12VDC and check out the spray pattern too. make sure they all spray with a reasonably similar pattern.
just leave the fuel rail off the car and give it some pressure. you'll know pretty quick what's going on.
Feed each injector +12VDC and check out the spray pattern too. make sure they all spray with a reasonably similar pattern.
10-08-2008, 06:11 PM
#3
Well it seemed like a great idea, but my fuel line will not pressurize. I guess some sensors are required before the fuel pump kicks in. Anyone know what I need connected or which wires i can power directly on the pump to get my fuel rail pressurized? Thanks!
10-08-2008, 07:03 PM
#4
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Join Date: Sep 2008
Posts: 14
Silly question, but did you put the FP fuse back in?
10-08-2008, 07:32 PM
#6
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Join Date: Sep 2008
Posts: 14
My bad. I thought fuse removal was part of the fuel pressure relief procedure. I thought about doing what you're trying to do, but just went ahead and carefully put it all back together (after ohming out the injectors). I was careful with the insulators that sit beneath the fuel rail as well as lubing up the injector o-rings and carefully placing them into the installed fuel rail. After that I was pretty certain it wasn't going to leak.
10-10-2008, 04:04 AM
#9
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Posts: 14
10-10-2008, 11:57 PM
#10
Yes, plug one side! 20-40 psi is good, you're just looking for any possible leaks due to a damaged oring during the assembly process! Cause that's alot of crap to take back off if there's indeed a leak!
10-11-2008, 03:32 AM
#11
Further more, the last thing I want to do is spray soapy water on my newly cleaned injectors!
CapedCadaver, I grounded all of the harness grounds and the rail will still not pressurize. Perhaps the injectors must be connected for the fuel pump to kick on?
10-11-2008, 05:16 AM
#12
Senior Member
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
Unless your air compressor has a water filter (mostly for painting purposes) you are putting water in your fuel line and injectors by testing the rail with this method. Even without water, air in the fuel line/injectors is not only difficult to purge but will contribute to rust on internal injector parts.
Injectors couldn't give a toss about water - its stainless with no stationary or moving parts being susceptible to water "damage" ........................... yes sure water will cause a misfire after passing through the injectors at the time of combustion but that is all, but given the only minuscule amount of water you can actually deposit in reality on the inside of the fuel rails by using compressed air, its effectively a non-issue as it will soon be removed by either getting injected into a cylinder when fuel once again starts circulating or it will be recirculated back to the tank where once again it will soon get "consumed" because of fuel action.
I say pressurize (50lbs), with air the rail assembly before you stick it in the car and dump the whole assembly in a bath of warm/hot water - leave it there and go have a beer - come back and look for bubbles - if you do you know what to do ..................... successfully used this technique many times and imo its guaranteed to be the fastest way to check an overhauled fuel rail assembly's integrity while its off the motor
10-11-2008, 06:48 AM
#13
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Join Date: Sep 2008
Posts: 14
Unless your air compressor has a water filter (mostly for painting purposes) you are putting water in your fuel line and injectors by testing the rail with this method. Even without water, air in the fuel line/injectors is not only difficult to purge but will contribute to rust on internal injector parts.
Further more, the last thing I want to do is spray soapy water on my newly cleaned injectors!
CapedCadaver, I grounded all of the harness grounds and the rail will still not pressurize. Perhaps the injectors must be connected for the fuel pump to kick on?
Further more, the last thing I want to do is spray soapy water on my newly cleaned injectors!
CapedCadaver, I grounded all of the harness grounds and the rail will still not pressurize. Perhaps the injectors must be connected for the fuel pump to kick on?
. Bottom line seems to be that if you're really carefully with the o-rings and get them lubed up, they're not going to tear putting them into the fuel rail. If the injectors and o-rings are good it's not going to leak.
10-11-2008, 05:14 PM
#14
"Since the internals of injectors are made of various steel alloys, they will corrode or rust. Once the fuel inside dries out, the deposits inside harden and the pintle can stick to the seat making it inoperable. There is enough moisture in the air in most parts of the U.S. to cause corrosion with the pintle and seat will not seal and give you a leaky injector if allowed to happen."
Im not willing to take a risk on my newly cleaned injectors with air/water since I just paid a lot of money to have them cleaned of rust and corrosion. Please get back to the OP, pressurizing my fuel rail with FUEL.
10-11-2008, 05:39 PM
#15
chris i think you're gonna have to use some jumper wire to force the fuel pump to come on. heck i guess you can just pull the rear seat and put a battery right there to jump it with
10-11-2008, 07:24 PM
#16
Yeah, with your help thats just what I did. Ironicly the black lead on the fuel pump is the positive lead, it took me a minute to figure out why I could hear the pump running but pressure was still at 0. Thankfully, I have no leaking at 46psi so everything is well. Thanks for everyones help and ideas.
10-12-2008, 10:48 PM
#17
Unless your air compressor has a water filter (mostly for painting purposes) you are putting water in your fuel line and injectors by testing the rail with this method. Even without water, air in the fuel line/injectors is not only difficult to purge but will contribute to rust on internal injector parts.
Further more, the last thing I want to do is spray soapy water on my newly cleaned injectors!
CapedCadaver, I grounded all of the harness grounds and the rail will still not pressurize. Perhaps the injectors must be connected for the fuel pump to kick on?
Further more, the last thing I want to do is spray soapy water on my newly cleaned injectors!
CapedCadaver, I grounded all of the harness grounds and the rail will still not pressurize. Perhaps the injectors must be connected for the fuel pump to kick on?
Be careful with that fuel guys you could create a minature fuel/air bomb!!!
10-13-2008, 01:03 AM
#18
Senior Member
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
I have the injectors/fuel rails installed on the engine and the last thing I do is spray soapy water around the lower IM and fuel rail area while pressurizing the fuel rail with air looking for any possible leaks (damaged orings) after assembly of the fuel rail and injectors but B4 final assembly of the upper intake plenum for insurance! Who's stupid enough to submerge thier injector in water period...It ain't that kind-a-party over here buddy!
Say/think whatever you want - I hate unnecessary duplicate work interfering with my beer drinking time.
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