Measuring Block 23 VCDS - Explanation of results

[Peter_222]

Hey new to this.

would like to know what I should expect to see at block 23 on vcds for my 2002 1.9tdi pad 130 avf engine. The values are currently between -65 to -88 at idle. This goes up to between -100 to -130 when driving.

The car has been causing me a lot of problems with cold starts/left for a few hours. i think the seals of injectors need done but I still think there's more to the problem in regards to a fuel restriction.

Any help would be greatly appreciated.

Peter

[Oski]

Hi. Negative values indicate a problem with fuel feed. Theres a big change of air getting in to system, so I would replace orings, and check fuel pipes for any traces of diesel. Also check vacuum pump on the back of engines head. Can you do a log of groups 13, 18 and 23 and post here? Start logging before you attempt to start the car.

[Peter_222]

Hi.

ive only just got the vcds and I'm still learning. Can I log all three groups at once? And should I log whilst driving?

What should I be looking for in regards to the vacuum pump? My mechanic has claimed to have changed the gasket already. Is there anyway to check the pressure coming out of it?

Also when I turn on ignition ten times before cranking allowing lift pump to build pressure the car starts a lot easier. Could this be a clogged or failing lift pump under the back seat?

thanks

P

[Oski]

Yes, log three groups at once, at idle. Pump inside the tank just builds pressure in the system.

What you could try is unplug feeding and returning pipes from a vacuum pump, then get two spare fuel pipes approx 1.5m long, plug one side to vacuum pump, the other end stick inside a container filled with fuel put on the ground. See how it starts. With this method you can check aux pump in the tank. Do not forget to loop pipes you unplugged