Good morning all, I have a new problem which after a few weeks of trying I can’t resolve and wondered if anyone had any ideas. 
 

basically when I turn the ignition on and the fuel system primes itself, the pipe going from the high pressure pump to the fuel rail pops off the fuel rail. I tried a new clip and seemed to work for a week but yesterday same thing happened. 
 

yeaterday I changed the pipe so it’s now a new piece of pipe, new clips and it seemed ok. This morning it popped off again. As it’s MOT day I’ve secured it with a zip tie around the clip and the rail to hold it and it works but certainly not ideal or right.

 

anyone any ideas please? 

I'd want to be finding the root cause - has something changed? Is it a new, higher pressure pump? Can you get a pressure gauge on and check it's not too high?

I assume by 'clip' you mean a decent jubilee clip and not some wimpy thing? 

 

Thanks Nelmo. Nothing has changed since IVA 3 years ago. Just under 5000 miles on it and runs and drives like a dream. I started thinking maybe blocked injectors causing back pressure but it runs fine so can’t work it out. 
 

in other news, failed the MOT with the GBS emissions map on. Needed a reading of 0.3 I had circa 8! Apart from fitting a lambda it’s as per IVA. Such a shame as it’s perfect weather for it this week 

Faulty fuel pressure regulator could cause the pressure in the fuel rail to rise to high as it wouldn't be bleeding excess fuel back to the tank.

Higher than expected fuel pressure would cause it to run rich, which won't help emission.

I'd be looking at the regulator first.

I don’t have a pressure regulator. Was told I didn’t need one when building so never fitted one. Have I messed up?

im running a Ford setup, 2.0l zetec, GBS plenum and everything provided by GBS (except a few bulbs and interior trim)

The pressure regulator will be bolted to the fuel rail. It should have a small vacuum pipe connecting it to the inlet manifold / plenum.

https://www.ebay.co.uk/itm/380284249173

Edited July 17, 20215 yr by richyb66

Mmmmm, don’t think I have one of those! I did get a regulator from GBS but they then said I didn’t need it unless it’s built in somewhere? I will get some photos at the weekend. Looks like it’s going to be too wet to MOT this weekend now and I work away from home in the week. 

Aha, stumble across this thread - puts the emissions saga into context!

As richy says, if your fuel pressure is way too high (which it sounds like) that would explain it running rich and failing the emissions test. I would check your regulator - there must be one somewhere, you can't run an injection system without one!

if you are running the standard zetec fuel rail then the regulator is part of the rail if my memory is still working 

That rings a bell. I will have a look at the weekend and post some pics or a video of my setup. Odd that this has happened with nothing being changed in my mind by I’m sure there’s a reason. 

is your fuel return line blocked?

2 hours ago, Grim said:

is your fuel return line blocked?

This seems the most likely explanation, maybe a kinked or collapsed hose somewhere between the FPR and tank?

As a diagnostic you could try to wire your fuel pump up directly to a (switched!) 12v source so it can run without the engine running, then listen in the engine bay for the sound of fuel flowing around the system via the return line.

Great shout, thank you very much. I will have a play at the weekend 🤞🏻

So, fuel is getting round the system.but doesn’t seem like it’s as it used to. I used to be able to hear the excess fuel clearly entering the tank after it had primed, but now it’s barely audible. I’ve removed the regulator and considering a replacement as I’ve checked all the fuel lines and they all seem as they did when I built it. 

Worth pulling the return line off and, after ensuring it's FULLY DRAINED AND CLEAR OF ANY PETROL ;), wipe it nice and clean and give it a bit of a blow (ooer missus) just to ensure it's not obviously blocked....?