ALH air in fuel lines after sitting overnight

Herm TDI

Vendor
Joined
Nov 21, 2001
Location
Richmond, Maine...The far side of Witsend
TDI
2002 Golf GLS Malone Stage 3, P+520 nozzles, 11MM Inj pump, Sachs VR6 clutch, Stelth Race Pipe, Immo Deleat, EGR Deleat
Hello people,

So here’s the deal, I had an issue with my Jetta sputtering a bit when started after sitting overnight, after researching and discovering the thermo T issue, I decided to change over to a CAT filter on a Wix base. While I was at it I replaced the rubber fuel lines from the hard line to filter, from filter to IP, and the return from the IP to the return hard line. Also the injector return lines. Well, the problem persists, one way or another air is getting in the lines and causing rough starts and rough idle for a several seconds till it works the air out of the system. Where do I go from here?
I even tried a whole new filter and new base as well, with no change.
I also removed the filter and base (assembled) and pressure tested it but couldn’t find any leaks.

Any ideas appreciated.
Thanks
On the injection pump body there is a fuel shut-off solenoid. The solenoid has an o-ring. Yours is likely dried out brittle and leaking air into the system.
 

J_dude

Veteran Member
Joined
Jan 9, 2020
Location
SK Canada
TDI
2003 1.9l “Jedi”
On the injection pump body there is a fuel shut-off solenoid. The solenoid has an o-ring. Yours is likely dried out brittle and leaking air into the system.
Thanks, I have since verified air intrusion is not the issue (at least, not anymore).
Good tip for anyone else looking at this thread down the road though.
 

J_dude

Veteran Member
Joined
Jan 9, 2020
Location
SK Canada
TDI
2003 1.9l “Jedi”
Take an 001-004 log i guess? Did you set pump timing down where I suggest? Halfway from red to blue?

Also could take 004 only log, just note try coolant temp
What are your injector balance readings in measuring block 13?
Guess I'll do this tomorrow, in the middle of injectors on the truck today.
 

ts888

Veteran Member
Joined
Feb 18, 2023
Location
PNW US
TDI
03 ALH
Thanks, I have since verified air intrusion is not the issue (at least, not anymore).
Good tip for anyone else looking at this thread down the road though.
I should check this. I get a bubble in the clear line when the car sits overnight. Doesn't affect starting or running, but it still bugs me...
 

Prairieview

Veteran Member
Joined
Jul 9, 2017
Location
Too close to Sturgis 'ithole
TDI
Two 2000 Beetles, 2002 Jetta, 2002 gas avh Jetta, fleet of older 1.6 turbo and non's
Soon, only criminals will have air bubbles.

This whole things reads like an old woman's soap opera.

I have a fleet of older 1.6's and ALH's in constant service. When I acquire or put together any of these, I literally toss the "clear" lines and sub-in black rubber lines from O'reilly's, etc. I reseal the pumps and also TOSS the re-cirulating fuel filters and "T" fittings. I keep good 1/8 inch black plastic line between the injectors (bleed-off) and I am NEVER walking or wimping around trying to get one started in cold or hot weather.

A simple life.....is a good life.
 

fatmobile

Veteran Member
Joined
Jul 16, 2019
Location
north iowa
TDI
an ALH M-TDI in a MK2, a 2000 Jetta, 2003 wagon
On the injection pump body there is a fuel shut-off solenoid. The solenoid has an o-ring. Yours is likely dried out brittle and leaking air into the system.
Isn't that under pressure?
When it opens it allows fuel from inside the pump, which is at over 35psi even at idle, to go to the injectors.
If so you would see fuel leak out instead of pulling air in.
 

J_dude

Veteran Member
Joined
Jan 9, 2020
Location
SK Canada
TDI
2003 1.9l “Jedi”
What are your injector balance readings in measuring block 13?
All within spec, not too bad really.

Also, changing the pump did seem to improve the cold start, still not perfect but it's better. I think I'm just going to order some injectors...
 

bowlerman

Veteran Member
Joined
Jul 31, 2001
Location
medford, NJ
TDI
2001 jetta tdi black
i will say i wasnt a believer in the fuel filter o rings till yesterday. replaced my ip and still had air. i had just fuel and had to put a new sender and clean tank. then i had solid fuel at hose to fuel filter. so i put a new filter and new orings. NO one even the book shows where the blue and black go. the black seems bigger so i put that top and blue on bottom. after that solid fuel. i thought my ip was bad but seemed to be clogged fuel sender and leaking o rings. just some experience.
 
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