Connect the boost pressure gauge properly, no shortcuts!

Hello everyone!

I have an ALH engine and would like to know the best way to connect the LDA (Linear Density Airflow sensor) in the engine compartment.
I think I read about a hose with a syringe needle attached to it in some old forums. This hose is then simply inserted into the rubber hose connector at the intake manifold.

'However, I want to install it properly and not just do a sloppy job. It can't be properly sealed if the needle simply gets inserted like that; the pressure could push it back out.'

Has anyone had any experiences or tips on how to do this better?


Thank you very much for your suggestions.

Best regards,

Hi.

In my wife's ALH-Ibiza, I also installed a boost pressure gauge back then.

As a replacement part, I took the pipe section with the EGR valve and shut-off valve.
On one side, the membrane housing is attached to the bypass valve. Conveniently, there are similar threaded holes with an M5 thread on the other side.
I drilled one of them through into the intake manifold and then screwed in a homemade pressure fitting from the outside – and that was how I created the connection. However, I had to carefully remove all the drilling chips from the AGR component afterward.

Thanks to a pressure gauge with a vacuum range, the function of the shut-off valve can now be monitored simultaneously, and in the event of any potential issues... Check to see if the thing closed up during the engine run.

During the initial test drive, a familiar problem arose: the needle vibrated depending on the engine speed.
The cause is pressure waves in the intake manifold, generated by the opening and closing of the intake valves, and pulsations from the EGR pipe, which are transmitted into the instrument.

I was able to eliminate the problem with a piece of hollow spray tube, approximately 4 mm long, which I inserted into the silicone hose from the engine side (the inner diameter of the hose happened to match the outer diameter of the spray tube).
Other colleagues insert a piece of foam into the hose.

By the way, while reinstalling the retaining flap housing, I noticed that it can also be screwed on in a way that the flap doesn't open completely. Therefore, when dealing with unexplained performance issues, it's worth investigating in this direction as well...

(For those who might recognize this text: it appeared in a slightly different form in the old forum.)