4.6 spitting o-rings out of 2 injectors

[skidad]

Hello, We bought a 2001 Mustang GT with only 14k miles this summer (all parts are original) ** This problem was also posted in old thread but thought I would make a new too.

We have had the drivers side rail lift up 2x on us on cylinders 5 and 6. Did it about 1 month ago and I replaced top o-rings on injectors 5 and 6. I also bent the rail support piece back to 90 degrees. I chalked it up to previous owner. I may have pinched #6 o-ring when I put things back together last time b/c the other day it spit out part of the o-ring and lots of fuel. A little confused b/c it took a month before that happened.

I've ordered 8 injector clips and new top o-rings - the car never came with injector clips from what I've read, which is wild.

Anyone ran into that and successfully solved this - only happening on Cyl 5 and 6 with 6 being the most dramatic both times. Not wanting to change to aftermarket rails at this time.

thank you

 

[squeak93]

Clips are not needed, the bolts on the rail hold down just fine. Replace O Rings, lube up prior to install. It's possible that with those low miles you have some crazy injector clog or something.

 

[Mustang5L5]

Agree. Clips aren't necessary. The design of the fuel rail is such that pressure from the bolt-down hardware keeps the injectors in place.

Of the rail has bent upwards, it may be compromised now and you likely will need to replace it.

 

[skidad]

the rail is NLA from what I can see - i looked at it and it looks great except for the front support piece. I might weld another piece of metal there to beef it up.

what's odd is the injector is not lifting, just the rail - the 1st time I could see the blue o-rings from the side. this 2nd time it ripped the one in half.

as for a clogged injector - wouldn't that throw a code or cause some running issue? - car runs like new. I'll be working on it all on Saturday

 

[DadLife0724]

the rail is NLA from what I can see - i looked at it and it looks great except for the front support piece. I might weld another piece of metal there to beef it up.

what's odd is the injector is not lifting, just the rail - the 1st time I could see the blue o-rings from the side. this 2nd time it ripped the one in half.

as for a clogged injector - wouldn't that throw a code or cause some running issue? - car runs like new. I'll be working on it all on Saturday

My first thought would be the injector isn't seating into the fuel rail properly. What o-rings are you using?

 

[skidad]

My first thought would be the injector isn't seating into the fuel rail properly. What o-rings are you using?

well the 1st time it was the stock blue ones. the next time I used some blue ones from that fit my ls1 engine -they looked identical. I've ordered the motorcraft ones this time - they are black CM4717

 

[Mustang5L5]

The rail is lifting by physically bending? Do you have an aftermarket intake (dorman replacement) or a factory PI intake.

Popped my hood to take a peek and there is one bolt at the front by injector 5 and the other near the rear. Grabbing between injector 5 and 6 and pulling up I get zero flex. Nothing at all.

Is the rail on yours bending? Is that front bolt in place?

 

[Mustang5L5]

Can you post some pics? I’m wondering if there is a parts mismatch somewhere. This really should be straightforward. I’ve pulled the rails of these cars plenty of times and those injectors are pretty locked in under the rail if tightened down properly

 

[skidad]

the 1st 4 pictures are when it happened a month ago. 1st one show the rail support bent back to 90 degrees after my repair. the next 3 shows bent rail support and how the o-rings were popping on 5 and 6.

the last 3 pictures are of what I saw when I pulled the rail off this week - all 4 of the o-rings are blue - i didn't take off the passenger side b/c it's been fine. It's possible it was an issue the previous owner had and never mentioned - it was a rough story of a lady that owned it that has dementia really bad. I didn't ask her husband a lot of questions b/c of this.

i put a straight edge on the rail and it's not bent - just the front support piece.

 

[DadLife0724]

It looks like someone was in there at some point and used the wrong o rings.

 

[skidad]

I'm not sure - i see blue ones on these that were pulled out of an engine - https://www.ebay.com/itm/1280833206...pid=5335821607&customid=&toolid=10001&mkevt=1

but I did order a new set of motorcraft orings

 

[DadLife0724]

It may just be the angle of your picture but the o ring definitely looks too big. Hope your new ones fix your issue.

 

[squeak93]

Definitely looks like rings are binding either from improper lube or being too big. Are you putting oil or something on them to lube before installing on the rails?

 

[Mustang5L5]

Those injectors just look short to me, but hard to tell from the pic. They are pretty standard so I can't imagine that is the case. I can't take a pic right now, but mine are further up into the rail that than that.

I also agree that the blue O-rings look a little bit large. I also recall my stock o-rings being black, not blue. If they are the incorrect o-rings, using a petroleum based lube could cause them to swell as well. Use a silicone o-ring grease instead.

 

[skidad]

yes I did use o-ring lube on them. well you guys got me thinking - I measured the orings i used to replace the 2 and they 10 thousandths larger than the one i pulled out originally. I probably should have used my caliper to measure them then. I will measure the black ones that I'm picking up later. This might explain my 2nd issue (i feel stupid right now) I pretty much chalked the 1st time up to someone bending the rail on purpose when they change a spark plug or something. Will report back