Alh prime fuel pump with vcds

Alec2003

Active member
Joined
Sep 21, 2021
Location
Quebec
TDI
Alh
Is their a way to prime the fuel pump with vcds on a Alh motor? I'm pretty new with vcds and didn't found nothing
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Or..... just get a big basting syringe for $2 at walmart. Pull the return line off the IP and keep sucking the air out. It takes a while but eventually you will draw fuel though it and the job is done. No injector priming...... easy peasy
 

Alec2003

Active member
Joined
Sep 21, 2021
Location
Quebec
TDI
Alh
Or..... just get a big basting syringe for $2 at walmart. Pull the return line off the IP and keep sucking the air out. It takes a while but eventually you will draw fuel though it and the job is done. No injector priming...... easy peasy
I will surely try this thanks man!
 

greengeeker

Vendor
Joined
Feb 8, 2006
Location
Cambridge, MN
TDI
2002 Jetta GLS
I have a fuel priming bulb (like you'd see on a boat) that I plumb between the filter and the IP supply line. Sometimes is necessary when the IP oring is leaking so badly that I can't create a vacuum on the IP outlet side with mityvac.
 

jef@rosstech

Associate Ross-Tech Vendor , w/Business number
Joined
Jul 19, 2010
Location
knoxville
TDI
2004 Dog hauling, wood towing, pinball stashing Jetta wagon
Nope, ALH doesn't have a lift pump.
Correct.

just get a big basting syringe for $2 at walmart.
Pretty much the correct answer.

With the ALH engine, the VE pump sucks the fuel. So to "prime" the system, you need to apply vacuum at the fuel filter to suck fuel from the tank and into the filter. From there, hook the fuel line back up and start the engine.

In some cases, if there is going to be air in the metal fuel lines and injectors, you might need to crack the injectors loose, crank the engine over a bit to purge out air.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Most of the time... if the IP has mostly fuel in it... it just means longer cranking time.
Its happend to most of us where we run out of fuel for whatever reason... get some help on the road and have to just crank it till it starts. It takes a while and hope you have a good battery and it's bad to run the IP dry like that but it is possible.
Just saying... prime the IP and crank it till it starts. Unless you have crow foot or fuel line wrenches .... and can bleed the 3rd injector properly... it's best to not possibly damage it....
 

Alec2003

Active member
Joined
Sep 21, 2021
Location
Quebec
TDI
Alh
Correct.


Pretty much the correct answer.

With the ALH engine, the VE pump sucks the fuel. So to "prime" the system, you need to apply vacuum at the fuel filter to suck fuel from the tank and into the filter. From there, hook the fuel line back up and start the engine.

In some cases, if there is going to be air in the metal fuel lines and injectors, you might need to crack the injectors loose, crank the engine over a bit to purge out air.
Thanks for your knowledge!!
 

Alec2003

Active member
Joined
Sep 21, 2021
Location
Quebec
TDI
Alh
Most of the time... if the IP has mostly fuel in it... it just means longer cranking time.
Its happend to most of us where we run out of fuel for whatever reason... get some help on the road and have to just crank it till it starts. It takes a while and hope you have a good battery and it's bad to run the IP dry like that but it is possible.
Just saying... prime the IP and crank it till it starts. Unless you have crow foot or fuel line wrenches .... and can bleed the 3rd injector properly... it's best to not possibly damage it....
What does IP mean? And yes I will bleed the injector that way
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
IP - Injection Pump
QA - Quantity adjuster
IQ - Injection Quantity

You move the QA (box looking thing on the top of the IP body..... to adjust the IQ and you need VCDS (software) to make sure you get it right but you can swag it close enough with hammer mod in a pinch till software is available. The part with the lines coming off the IP is the Head.

3 terms you will see ALL THE TIME on these engines and all pertain to how the IP works
 
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