About a month ago I noticed a leak around the #1 injector. I took the car to Ford, who diagnosed I needed replacement fuel return pipes. A month later and the return pipe popped out of the #1 injector. Ford have had the car back in, checked everything over and gave it the all clear, but the problem reoccurred within a day. I plan to take it back in again, but I'm curious if anyone has ideas what might be causing this beyond shoddy workmanship or a duff set of return pipes.

Ford have told me the injectors have been tested and are working correctly, so that's at least one thing off my mind. They also said the return pipes aren't under any significant pressure that would cause them to disconnect. It all seems a bit strange, but this is well beyond the scope of my knowledge.

Any ideas?

are the return pipe clips inserted securely? its a small silver/green clip that is inserted around the injector that locks the pipes into place. if you could get a picture of the injector with the return pipe that would help

the clip looks like this

I've attached an image to the original post. Forgot to also mention that after the first time it went back, it also occurred on the return on Injector #4. The picture above was taken before I pushed the return back in. Both times I've had to do that they've given a reassuring click and don't easily feel like they would pull out again.

Anybody find out what was wrong with his return pipes coming off? I have the same issue but its pressure related. It seems that fuel pressure is getting too high but the return pipe back to the tank is completely clear. Somehow there is pressure coming into the return pipe inbetween the actual return pipe on the injectors and the main return fuel line leading back to the tank. Inbetween there is a t piece that connects to a pump and I think something has gone in the pump like a valve or something that is causing excess pressure going in the return line that connects straight to the injectors which is causing the lines to pop off because the pressure is too high to escape back to the tank as it is an abnormal load. Any suggestions would be muchly appreciated. I've read about problems with the return pipes popping off and mine is the same situation as the OP but there doesn't seem to be any real solutions/answers online. Could be the fuel pressure regulator/sensor?

Edited November 28, 20214 yr by Nic ggg
Added information

On 11/28/2021 at 6:32 PM, Nic ggg said:

Anybody find out what was wrong with his return pipes coming off? I have the same issue but its pressure related. It seems that fuel pressure is getting too high but the return pipe back to the tank is completely clear. Somehow there is pressure coming into the return pipe inbetween the actual return pipe on the injectors and the main return fuel line leading back to the tank. Inbetween there is a t piece that connects to a pump and I think something has gone in the pump like a valve or something that is causing excess pressure going in the return line that connects straight to the injectors which is causing the lines to pop off because the pressure is too high to escape back to the tank as it is an abnormal load. Any suggestions would be muchly appreciated. I've read about problems with the return pipes popping off and mine is the same situation as the OP but there doesn't seem to be any real solutions/answers online. Could be the fuel pressure regulator/sensor?

Don't suppose you figured it out. I've got same problem with 1.8tdci and iam searching through threads looking for answers or ideas. Iv replaced leak off pipe. But used old clips. Iv got new clips coming in the post. I tried a tie wrap to hold leak off nozzle in place and then another pops off. Works fine for 1st 30s then just starts to leak more than you would expect. But runs n sounds fine. Iam at a loss at min and searching through the net for answers, ideas or links.

 Noticed a lot of threads with same sort of problem and not found answer. When I do get an answer or figure it out myself. I may just leave a link at bottom of all in answered threads to my particular solution. If I get one. Fingers crossed.

Just spotted this and if clips don't fix it (doesn't look likely from what you say as there does appear to be excessive flow/pressure) I offer the following quick thoughts...
If there is excessive pressure in the return line I would measure it (Mityvac or similar) or, possibly much easier, disconnect then fit a pipe to take both ends to a container to see how much flow there is.
There are multiple You Tube videos of leak off tests (e.g. Alan Howatt) which include amounts of flow into the individual small containers so if lots of flow then individual injector rates would need to be determined.
If it's not injectors then it may be excessive flow from fuel pump return - again, measure into container?

Of course, checking return pipe isn't blocked or kinked and free all the way and into the tank is crucial as well?

How does that sound?

10 minutes ago, Shearers said:

Just spotted this and if clips don't fix it (doesn't look likely from what you say as there does appear to be excessive flow/pressure) I offer the following quick thoughts...
If there is excessive pressure in the return line I would measure it (Mityvac or similar) or, possibly much easier, disconnect then fit a pipe to take both ends to a container to see how much flow there is.
There are multiple You Tube videos of leak off tests (e.g. Alan Howatt) which include amounts of flow into the individual small containers so if lots of flow then individual injector rates would need to be determined.
If it's not injectors then it may be excessive flow from fuel pump return - again, measure into container?

How does that sound?

I have seen leak off tests. Not done one yet. And am not sure what you mean by mitvvac is that some sort of pressure testing gauge? And iam also not sure which 2 ends you mean. Really sorry. Just for info it's the 1.8 KKDA engine. I pulled an injector and was filthy.. sludgy n gritty. Cleaned it and the port best I could. I just found a post on the return 1 way filter by a member who has helped me no end of times and to be fair he is usually spot on. Now I am thinking he's more than likely correct as if my injectors are filthy then chances are that's what's caused the blockage. So am thinking to check that out first thing and maybe even get a cleaning kit for the injectors and port holes. Iv used a different fuel filter recently. I usually use Bosch but I went for Delphi... Surely Delphi not bad! Been in around a month. Maybe a bad or faulty filter caused it?

Anyway... Thank you for the reply and I will research your method and the other. Either way or what I do I will post my solution or fix. 

Mityvac is a pressure & vacuum tester but the leak off test looks like the way to go to me (including any output from the fuel pump leak off.
If you remove the leak off pipe from the injector, you will have two open ends so if the engine runs you need to arrange for both ends to be connected, otherwise you'll have diesel all over the place (a bit like now, sorry!)
Injectors are very precisely made and poking the teeny weeny ports is likely to put them out of calibration so personally I wouldn't do that.

Do come back with the leak off test result from each injector and fuel pump port plus confirmation that the return pipe is totally clear (I can't wait!)

4 hours ago, Shearers said:

Mityvac is a pressure & vacuum tester but the leak off test looks like the way to go to me (including any output from the fuel pump leak off.
If you remove the leak off pipe from the injector, you will have two open ends so if the engine runs you need to arrange for both ends to be connected, otherwise you'll have diesel all over the place (a bit like now, sorry!)
Injectors are very precisely made and poking the teeny weeny ports is likely to put them out of calibration so personally I wouldn't do that.

Do come back with the leak off test result from each injector and fuel pump port plus confirmation that the return pipe is totally clear (I can't wait!)

I meant I cleaned out the hole that the injector came out of. I only wiped thee gunk off the bottom of the injector

5 hours ago, Shearers said:

Just spotted this and if clips don't fix it (doesn't look likely from what you say as there does appear to be excessive flow/pressure) I offer the following quick thoughts...
If there is excessive pressure in the return line I would measure it (Mityvac or similar) or, possibly much easier, disconnect then fit a pipe to take both ends to a container to see how much flow there is.
There are multiple You Tube videos of leak off tests (e.g. Alan Howatt) which include amounts of flow into the individual small containers so if lots of flow then individual injector rates would need to be determined.
If it's not injectors then it may be excessive flow from fuel pump return - again, measure into container?

How does that sound?

I have seen leak off tests. Not done one yet. And am not sure what you mean by mitvvac is that some sort of pressure testing gauge? And iam also not sure which 2 ends you mean. Really sorry. Just for info it's the 1.8 KKDA engine. I pulled an injector and was filthy.. sludgy n gritty. Cleaned it and the port best I could. I just found a post on the return 1 way filter by a member who has helped me no end of times and to be fair he is usually spot on. Now I am thinking he's more than likely correct as if my injectors are filthy then chances are that's what's caused the blockage. So am thinking to check that out first thing and maybe even get a cleaning kit for the injectors and port holes. Iv used a different fuel filter recently. I usually use Bosch but I went for Delphi... Surely Delphi not bad! Been in around a month. Maybe a bad or faulty filter caused it?

Anyway... Thank you for the reply and I will research your method and the other. Either way or what I do I will post my solution or fix.