Could I have bubbles in my fuel line? Resolved!!!!

[warthog]

I did see a couple of threads regarding bubbles in the line, but they did not actually say how it affected the car. Let me tell you what is happening:

I have 2003 Megane II 1.9 DCI with about 177,000 miles on it.

Here is what happens. As I am driving, the car all of a sudden looses power and slows down, as if there is no fuel getting to the engine. If I push the accelerator down to the floor, nothing happens. If I lift my foot off the accelerator and then press down again like normal, the car continues to work like normal.

This has always happened with the car, about 4 years, but it was intermittent and the mechanic really couldn't figure out what was wrong. I replaced the EGR valve, but it did nothing. I considered the problem a quirk.

The past 4 days, the problem has started to get worse, especially in low gear. I start driving and loss of power, I lift my foot and press down and we are back in business, but sometimes it happens like 5 times in a row. Other times it doesn't happen at all.

The car starts with no problems and idles with no problems. I have no Injector/injection warning lights... It is only under acceleration when this happens.

Now, based on my reading I am thinking it is the HP pump (hope not) or a hole in the fuel line letting air in. To me, it makes sense the air in the line, cause it's as if fuel is running through the injectors and all of a sudden there is a bubble, so no fuel, then fuel runs through it again... there may have always been a small hole, but now it's bigger???

I understand that the fuel line is a clear tube.. although I have no idea where it is. Does someone have a picture? Please note my car is a left hand driver.

Any advice or thoughts or pointing me to a previous thread I missed would be much appreciated!

[Colster]

I had the same symptoms as you are describing, and I did have air bubbles in my fuel line. I have only had the new pipe fitted for 24 hours. So far so good, so fingers crossed this is the problem. The clean white pipe in this picture is the new pipe. It might look slightly different on your car, as it will be a phase 1.

[Colster]

This is the old pipe. You can see where it has rubbed underneath. The part number for this pipe is on the bag.

[Colster]

This is probably the pipe you need. Part number can be seen on the bag.

[warthog]

Thanks so much for the pictures and info! I will look into it!!!

Just out of curiosity, is this something I can do or better done by a mechanic. I'm a shade tree mechanic with just basic tools.

Andy

[Colster]

It's not difficult - just awkward! You should be able to see bubbles in the fuel when the engine is running if your pipe is holed.

[gareyt]

if all you have to do is replace the pipe from the filter to the pump then you are laughing anything more and you might be struggling especially if you cant locate the fuel lines yourself.

the lines are located on the left side of the engine bay as you look at it. if you have the black plastic trim around the coolant cap then remove it and you will reveal the lines and a rubber bulb. Squeeze the bulb, if you see bubbles in the lines then you could have a problem. if the bubbles appear in the lines from the filter to the pump then replace the lines and I recommend the filter aswell.

If the car starts without fault then I don't think its air in the fuel as I believe this would be noticeable on starting much more so than when accelerating.

The car needs air as well as fuel in the mixture so maybe check the air inlet pipes and filter for blockages etc.

Next step is a mechanic and a wad of cash.

[Colster]

The chafed pipe between the filter and the pump is a common problem. Before I changed my holed pipe, the car started perfectly. Also, pumping the primer wouldn't replicate the fault I had, as the air was being drawn into the pipe under depression. I had the same symptoms as the OP, but they haven't recurred since I changed my pipe. If the pipe is found to be holed, and replacing it cures the fault, I don't see the logic in replacing the filter.

[Beast Rider]

You're looking in the wrong place for the cause of your cars symptoms.

Mine done exactly the same thing and it turned out to be the brake lights switch I change it about 18 months ago and haven't had a problem since, renault programmed into the ECU that if the brakes are pushed at the same time as the accelerator it will kill all power.

When you next go out gently push on the brake pedal with your left foot while driving along, if it gives the same symptoms then its the brake light switch.

A replacement part is about £18 and take 5mins to replace.

[warthog]

I haven't had a chance to take the car to the mechanic yet, but I did look under the hood and unfortunately all the pipes look to be in good shape I couldn't see any bubbles. This fuel deprivation seems to happen mostly at slow speeds, like when not a lot of gas is being applied. Today when I was pulling out of a parking lot, the issue was quite apparent and made it tough to get going... but once I play with the clutch and accelerator, I can get the car going and then the issue is not so frequent. I am just confused why it has gotten worse.

I don't think it's a brake light switch as I can not remember ever pressing the brake when pressing the accelerator. My foot would be on the clutch and accelerator... but I'll give it a try tomorrow.

Thanks for the ideas guys!

A

[Beast Rider]

the brake light switch sticks so after you have applied the brakes then go back to the gas the car thinks the brakes are still applied.

[Colster]

I think the brake pedal switch does warrant some investigation. Read http://www.meganeownersclub.co.uk/forum/viewtopic.php?f=2&t=21585 for more info.

[warthog]

I believe it does warrant some investigation... I am going to check right now. I assume the brake light switch and brake pedal switch are the same thing?

The other thread mentioned a manual... 37A-28 of MR364MEGANE2... but when I look through the pdf I found, it doesn't have that many pages!!

Thank you so much for sticking this out with me and coming up with other possible solutions!

A

[Colster]

Section 37A is in this manual. https://www.uas-bg.com/meganii/eng/MR364MEGANE3.pdf

[Beast Rider]

Yeah same thing i think, you should find it in the passengers foot well. It takes about 5mins to swap and costs about £18.