Pinched fuel line

#1

I was under the car today doing some maintenance and noticed that the fuel line closest to the outside of the driver’s side is pretty badly flattened. I believe this is the return line back to the tank.

What kind of result should we expect from this? I noticed that the car recently took on a rough idle.

Has anyone changed this line before? I’m hoping to not have to drop the gas tank to replace? Following the line back to the tank, it stays a hard line while going up to the tank. I’m not sure where it terminates?

I believe it’s #2 in the picture below. Please correct me if I’m wrong.

#2

You may need to drop the tank if you replace the entire line. I have an 89 and I have a combination of hard and soft lines that run between both sides of the tank. The only access I have it via the two openings on the back seat area to get to the senders and pumps. Not much room there.

You could consider cutting the line and splicing in a new piece of hard line. You will need some flaring tools but it may be easier and just as effective as replacing the entire line.

That job will be no fun regardless of approach taken to correct.

#3

Assuming you haven’t replaced the tank, and you still have the '87 dual pump setup, here’s a picture of my tank that I replaced on my '87. The two hardlines soldered to the tank are feed and return. I forget which is which. So, no, you shouldn’t have to drop the tank, as long as you can find the end of the hose coming off the correct line. Either way, bending new hardlines is a pain as well.

#4

Thank you for the picture. That is very helpful. It appears that Pelican sells the hardline, so that might be the route to go.

#5

You don’t have to drop the tank to replace either of the hard lines under the car. Both lines terminate fuel hose before they go to or over the tank.

#6

This is good news.

Could my recent rough idle be because of this?

#7

Don’t over think this one, but do not your lines terminate in rubber hose on both ends?

Yep, it is fuel were talking about…cut and splice the smished (new word) metal line with good flares and a short section of hose?

RP

It could have an effect on idle 'cause the smished line is causing too much fuel restriction/fuel pressure…

#8

BTW, most of us smash that line ourselves by jacking the car up and missing that frame rail. Done that more than once :angry:

#9

andrew240z wrote:

Yup, that’s why I ended up replacing my lines. I got new ones from the dealer. There were rubber lines coming down from the engine compartment and rubber lines back at the filter/pump, leading up to the tank. It was a pretty easy job.

#10

Patton wrote:

[quote]Don’t over think this one, but do not your lines terminate in rubber hose on both ends?

Yep, it is fuel were talking about…cut and splice the smished (new word) metal line with good flares and a short section of hose?

RP

It could have an effect on idle 'cause the smished line is causing too much fuel restriction/fuel pressure…[/quote]

That seems to be the most direct fix.

#11

Z3SpdDmn wrote:

[quote]andrew240z wrote:

Yup, that’s why I ended up replacing my lines. I got new ones from the dealer. There were rubber lines coming down from the engine compartment and rubber lines back at the filter/pump, leading up to the tank. It was a pretty easy job.[/quote]

Yup - I didn’t want to admit it, ;), but after some thinking back, that’s exactly I did.

#12

I’m trying to figure out what the correct part number is of the line that ideally needs to be replaced.

I traced the line back to the engine compartment and it goes to the carbon canister. So the diagram that I originally posted is for the wrong lines.

This is the correct area -

http://www.realoem.com/bmw/partgrp.do?model=1113&mospid=47309&hg=16&fg=10

Also it looks like I might have to drop the gas tank to get to the connection hose. The other two lines, are below/along side the tank, but this hard line goes to the top.

I still can’t put my finger on the right part number.

Andrew - do you remember?

#13

We didnt replace the lines, hasnt affected performance. you have something else going on unless the line isnt allowing any flow

#14

andrew240z wrote:

The car was running great at Road Atlanta. Recently the FPR was changed and the line was pinched. So I’m guessing it’s one or the other.

#15

The return line off the charcoal canister is just for vapor. If that is the pinched line I wouldn’t worry about it so much unless it is completely closed.

#16

I don’t think its worth replacing that line since its not critical. Just cut out the pinched piece and put a patch in. And you may not even need to do that. I don’t think that is making your car run rough.

That part of the systems is all about trying to be environmentally friendly with gas vapor.

#17

I see you replaced the fuel pressure regulator, but you say that may be at fault. I just recently replaced the fuel pressure regulator on a MINI. It was causing a rough idle and hesitation, so that could also be your problem. I checked it with a fuel pressure gauge and it wasn’t holding proper pressure at idle, it was actually 10psi lower than the residual pressure from the pump. After the repair the idle was smooth and no hesitation… Could be your idle problem.

#18

E30KDG wrote:

Good to know. I plan on swapping out the FPR with the previous one before tackling the fuel line.

#19

mahoneyj wrote:

[quote]I don’t think its worth replacing that line since its not critical. Just cut out the pinched piece and put a patch in. And you may not even need to do that. I don’t think that is making your car run rough.

That part of the systems is all about trying to be environmentally friendly with gas vapor.[/quote]

Good tip. Thank you.

#20

The rough idle was attributed to the FPR I swapped earlier. Apparently it was clogged up because when I disconnected it from the fuel rail it went shooting across the shop propelled by gas. Whoops. :lol: