AIR IN FUEL LINES

[vincie 247]

Hi, my work van a renault kangoo 1.5dci has air in the fuel line and is missing, i replaced the two pipes to and from the filter to pump thinking it was sucking in air at the connections, but this hasnt worked. Anyone any ideas?? what about the injector leak off pipes??

[BoraBora]

dont worry about it, is it causing an issue ?, theres air bubbles in my fuel return line all the time, theres a reason behind it i think

[vincie 247]

Yeh its causing problems, it has now got hard to start and is missing badly

[DaveBenyon]

I've got the same problem with a Renault Espace 2.2Dt and a friend has the same problem with his Grand Espace. The trouble is that if the problem gets really bad one might need a new battery, starter motor and ring-gear. My car does start perfectly when towed by a Land Rover but this is not the right solution. One school of thought is that the pipe stubs on the tank units crack and allow in air. I've had the tank out (yuk) but it isn't that. What is noteworthy however is the multitude of snap-action quick release fuel couplings made of plastic. If each one allows in a bit of air there will be a lot of air as there are so many of them. Allegedly ALL Renault diesels have air in the fuel as that is how they are. Some people just pay to have new pipes fitted whether it needs it or not but to be honest the build quality is just not there.

At a nearby HGV garage as soon as a lorry gets fuel problems they swap out the fuel line for one made locally from Cunifer Perrenic Auto tubing but this is not so easy on the Espace as its plastic!

I'm a "Senior" these days and I have owned dozens of cars but I'm sorry to say that the Espace is the worst and most troublesome car that I'v ever had the misfortune to own.

[Megaflow]

Which pipes do you suspect have air in and what makes you think they have air in?

[S0 What]

5 out of 10 times it's the filter seal, back in the old days it was 9 out of 10 but with so many fuel lines and stupid so called quick release unions it's the reason less and less, recently had a merc in that required 8 new pipes to stop it (pin hole in pipes, seals cut or oversize ect ect).
I take it the return pipes are clear and you can see the air? if they are what pipe is the air in after it's cleared?
from the filter susspect the filter seal/connection,
to the filter (from injectors) susspect the spill pipes
If you have the grenade type manual lift pump change it, they are cheap enough ?

[RetepSnikton]

Try parking facing down a steep hill, once the fuel tank is above the engine you may be able to see a fuel leak.

[v8250]

op, this is very simple to fix. isolate flow and return fuel lines from the tank. fit pressure gauge to system and manually pressurize. if system does not holding constant pressure for 10-15mins, carefully work your way along the fuel lines to find culprit and replace. it may be something as simple as a union needing tightening up. pay attention to the injectors and injector rail, and any flexible fuel lines. if fault is found on the rigid fuel lines replace all the lines, complete flow and return pipework. if you don't there's a high chance the fault will appear in another line soon.

if the f&r fuel line system [complete] is holding pressure then it's within the tank, sender, pump, filter area.

[T1pper]

If it starts with a pull but not by cranking it could be a fuel pressure problem in the common rail, the increased engine cranking by pull starting will compensate for a pressure drop/leak back in the rail.

I am not expert on the system but check fuel pressure leak of valve on the rail or possible injector fault, blank each injector outlet one at a time at the rail to isolate which injector is loosing pressure?

I have been able to tighten the injector gland nut on some systems to overcome a pressure loss??