Is it normal for a bubble to form in clear fuel line after sitting for days?

I've read many of the posts about bubbles being an issue in the clear fuel line.


Afterwards, I still wasn't clear on whether a bubble forming in the clear line when the car sits for days, or weeks, is a problem or not.


In my case a large air bubble - inch or more - will develop in the above scenario. Car runs and starts (2 - 4 cranks) well. There are zero bubbles in the clear fuel line while engine running at idling from idle. I use a bright light to back light the clear line when I'm examining it.


FWIW - I have already installed a new fuel filter and thermo-T fitting from idParts.


Just wondering if I'm over thinking it or do I have a problem.


Thanks

If you don't ever have any variations with how long it takes to start you are probably okay. Do you park where it is flat or on a hill? When my B4 started leaking around the IP it was more likely to loose prime when the nose was pointed up hill. IP leak started around the distributor head. If you don't see evidence of a leak and no starting issues you are probably okay.

Car starts and runs fine, no problem. Have you ever refreshed the little viton fuel return lines?

Mine has a bubble at the top after the car sits for a while. 3/4" or so. Has started the same way after 2 timing belt jobs that I've done so I think you're good to go.

BobnOH said:

Car starts and runs fine, no problem. Have you ever refreshed the little viton fuel return lines?

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Hey Bob - No I haven't at this point. However, I am considering new Bosio DLC injectors and DBW's hot swap program. It's my understanding they provide new return lines. Just haven't decided on DLC 520's or 1019's.



Car has 215,000 miles on it and I figure it's about time. Not looking for gobs of powers, still on OE clutch, but hopefully a slight FE increase and even better starting - especially in cold Wisconsin winters.



I plan on contacting DBW and ask for guidance on best injector for my purposes. Don't see a new turbo in the near future due to the fact previous owner had new Borg Warner VNT-15 installed at 200k.


What I do know is that I don't want to create fueling, smoke and FE problems by replacing injectors.

I used to get that same thing. Then I installed screw type band clams on the fittings at the fuel filter (including the thermo-t) and on the injection pump, refreshed the fuel return lines from the injectors to the pump, and greased the thermo-t fitting o-rings. No air bubbles now.

The engine starts exactly the same before and after.

I don't think you have anything to worry about.

Cheers,

PH