Doing a leak off test

[Clio 1.5 dci]

I've been having the warning lights appear on the dash for quite a while. Over the last few weeks my Clio hasn't been starting at all, presumably because of the injectors.

I've found a video on a leak off, so know where the plug in the tubes.


Who ever has done this before - what size tubes do I need (will save me buying the wrong size), and is there a need to clamp off the flow to the fuel pump which it looks like the guy in the video has done?

 

[Ads29]

It's not the easiest to see but it looks like (and should have) clamped off the return from spill/leak offs on injectors to the main fuel system, the idea being that you need to stop the flow of excess diesel back into the fuel system and 'force' it into your test rig in order to accurately measure and see a faulty injector.

As for pipe size I will have a look at my test kit, but I think it would be somewhere around 3mm tubing

 

[Clio 1.5 dci]

Yes, but I don't know which pipe that actually is looking at my engine bay? I don't want to block off the wrong one!

Please do let me know about the pipe size based on your rig after taking a look. Would I be able to pick up the pipes from B&Q/Halfords or so?

 

[Ads29]

I'll have a look now at the pipe size, I've also got 2 dci's on the drive so I'll take a look and get a photo for you

 

[Ads29]

My pipes are around 4mm internal diameter but are a few years old now so I'd go with 3mm personally, I know halfords do washer pipe which would be fine, somewhere else may do also

Where the main line meets the pump there is the return from the injectors, this may need clamping off but be careful as it's plastic not rubber

 

[Clio 1.5 dci]

Many thanks. Can I just confirm the clamping points. Is the yellow or green? Presumably these are the leak back lines?

 

[Ads29]

I've just had another look, shouldn't need to clamp either yellow or green, in fact don't clamp them or you'll fracture the lines. Pop off the 4 u shaped links off the injectors and connect up your test kit, that should be enough, if it's not send me another message and do some more head scratching

 

[Clio 1.5 dci]

OK, cool. So my kit gets attached to where those black curved pipes currently are on between the injector and the rail?

Shall I forget about the clamping of the line to the pump for the backflow of fuel?

 

[Ads29]

Yep that's it, and yeah forget clamping the return off to begin with, I think it'll do more damage than good, there is a little rubber link just above the t piece of the return should you need to clamp

 

[Clio 1.5 dci]

Thanks. Now I just need to try and get the car started!