Best way to identify source of fuel leak?

[AC_Schnitzel]

It’s unclear of where it’s coming from, and only happens when the car sits for a longer period of time (weeks).



The fuel is dripping from somewhere and making its way down to this line. (View from underneath the car facing the oil pan from in front of drivers side tire)

After the car runs for a bit, if I shut off and start again, the fuel stops leaking.

Which fuel lines run around/above the PS line?


Any thoughts?


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[jeffnhiscars]

The return line from the fpr is the only one on that side towards the front of the engine but it's the least likely to leak from sitting. If it's wet on that banjo can't you trace it

[AC_Schnitzel]

Nice. I'll check out a bunch of lines near the fuel rail and fpr.

[325e '87]

I didn’t have any leaking of gas on our cars, but, it was easy to buy 10 feet of new fuel line and replace the feed and return lines. Under the car there should be hard fuel lines that terminate inside the driver side frame just under the steering shaft u joint. The new rubber should route up and through the intake manifold and then split where the supply line goes to the fuel rail and return line from the pressure reg. For less than $30 you can just replace with new lines and clamps.

[jgilber0]

I didn’t have any leaking of gas on our cars, but, it was easy to buy 10 feet of new fuel line and replace the feed and return lines. Under the car there should be hard fuel lines that terminate inside the driver side frame just under the steering shaft u joint. The new rubber should route up and through the intake manifold and then split where the supply line goes to the fuel rail and return line from the pressure reg. For less than $30 you can just replace with new lines and clamps.

Agree. And you should do this sooner rather than later as there is risk of fire.

It took me about 2 hours to replace all of my engine bay fuel hoses, I suspect that others could do it faster. Not a big investment in time or parts for a big improvement in safety and peace of mind.

[AC_Schnitzel]

Agree. And you should do this sooner rather than later as there is risk of fire.

It took me about 2 hours to replace all of my engine bay fuel hoses, I suspect that others could do it faster. Not a big investment in time or parts for a big improvement in safety and peace of mind.

Sweet, do you have part numbers? Or did you just buy EFI fuel lines and cut/replace w/ the right hose clamps?

[jgilber0]

I bought BMW fuel line from BAVAuto, in three or four different sizes. Make sure that what you buy is high pressure EFI rated. I can’t remember all the part numbers anymore, but RealOEM was instrumental.

Check your system carefully before ordering, RealOEM showed a split system that sent fuel to both the front and rear of the fuel rail through a Y splitter, but my 1992 M20 had only a single feed line going to the fuel rail at the front of the engine.

Good luck! While you are in there, you should also do all of your vacuum and cooling hoses if you haven’t already done so.

[jeffnhiscars]

It's 8x13mm but I've bought some at the dealer which was 5/16 (which Napa sells for less). Either way it's bulk hose so you don't need a PN

[george graves]

I'll just echo what people said. Factory quality EFI fuel lines cost $$$. But cheaping out is a bad idea. Autozone will sell you anything, but the trust on it is very low.

If you park your car in an attached garage, all the more reason to get the real stuff. Then it's not just a leak, it can be a fire/life hazard. Just my 2 cents.

[dnguyen1963]

Hey guys,

The EFI hose is not made by BMW or Autozone. They are made by other companies and would have to meet very stringent requirements. Imagine if there is a fire and it is traced back to the fuel hose...the liability is enormous.

[AC_Schnitzel]

thanks for your responses.

Any idea if this is the right part + enough length? https://www.fcpeuro.com/products/bmw...13311722262-5m

Is 5 meters enough to do the entire car?

EDIT: there are other fuel hoses varying in inner/outer diameters labeled as "braided fuel/vacuum hose" -- https://www.fcpeuro.com/products/bra...m-od-x-30mm-id

What are the differences?

[dnguyen1963]

thanks for your responses.

Any idea if this is the right part + enough length? https://www.fcpeuro.com/products/bmw...13311722262-5m

Is 5 meters enough to do the entire car?

EDIT: there are other fuel hoses varying in inner/outer diameters labeled as "braided fuel/vacuum hose" -- https://www.fcpeuro.com/products/bra...m-od-x-30mm-id

What are the differences?

8X13 mm is the correct hose. 5 m is enough with some left over. The other hose is actually 5.5 mm...too small.

[AC_Schnitzel]

8X13 mm is the correct hose. 5 m is enough with some left over. The other hose is actually 5.5 mm...too small.

For sure -- I'll order the roll from FCP.

Noob question incoming:

When I go to remove these fuel lines, how do I minimize the amount of fuel spillage, and also reduce the pressure in the lines so that I can more-easily take them off?

[jgilber0]

For sure -- I'll order the roll from FCP.

Noob question incoming:

When I go to remove these fuel lines, how do I minimize the amount of fuel spillage, and also reduce the pressure in the lines so that I can more-easily take them off?

I let my car sit a few days before starting the job, and there was no pressure when I removed the lines.

I had almost no spillage, you can use forceps to pinch off the lines if you’re concerned.

[jeffnhiscars]

5m will do both engine compartment lines for 2 cars