1999 Air in fuel line

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#11

03-13-2019, 11:47 PM

Rock18

New Member

Join Date: Mar 2017

Location: Atlanta, GA

Posts: 99

Quote:

Originally Posted by Vovin

So why don't you just unveil the mystery and please explain what I should be looking for with a fuel pressure gauge in regards to air entering the fuel lines.

Gas/no gas out of the Schraeder is only a binary test and is not as indicative or quantitative about what's going as a leakdown test. So without a pressure test, you're sorta peeing into the breeze and then complaining publicly about how your shoes are always wet.

Basically, it's very possible for the fuel pump to generate sufficient pressure when activated but then a leak in the system lets pressure degrade more than designed when it's off, causing a bubble in the system. More troubleshooting is needed, but knowing these vehicles there's a decent chance this might be a sign the fuel pump itself is beginning to fail. A short-term workaround might be to turn the key on/off for 5-10 sec or so 2-3 times before starting to help prime the system on startup, which might get you through another month or two.

(EDIT: I know you're having a rough week here, but...) Being a jerk isn't usually going to suddenly up and inspire people to be more helpful either.

Good luck.

Last edited by Rock18; 03-14-2019 at 12:10 AM.

#12

03-14-2019, 02:32 PM

Tom A

BF Veteran

Join Date: Jul 2013

Location: Northeastern Nevada, USA

Posts: 2,417

Quote:

Originally Posted by Trukntigger

Well said but odd to have to say it, poster shows being a member here a long ways back. Guess thought is how can air get in front of pump and end up at the valve? The only answer is there must be a leak. It did not evaporate. *puts on Mr Spock outfit* logically speaking when engine off air is coming in from engine side of things allowing fuel to seep by gravity towards tank (no vacuum like blockage- think finger on top of a soda straw full of soda) and when you restart, pump pushes that air with fuel behind it towards engine. That pressure testing would help. Heck for all we know the shrader valve is acting like a check valve allowing air in when off but no fuel out when under pressure, very unlikely but I think point made.

I think a leaky injector would be much more likely. A leakdown test is the next step, regardless.