I purchased some RE90X silicon grease from Maplins the other day to perform what is called the ‘Cage Mod’ on the tdiclub forum. (Cage was the forum name of the guy who tried it first) It is supposed to help make a TDI engined Volkswagen Audi or Skoda run smoother by ensuring that the signals from each pin are fully isolated. I’m a bit skeptical but I thought I’d give it a go.
Firstly you need to locate the MAF sensor connector, in the VW Transporter T4 it is located on the left hand side of the engine bay just after the air filter and can be seen in the picture just above the blue lid of the washer bottle.
You then need to remove the MAF connector plug. To do this grip the connector, push down very slightly then press the tab and then pull the connector gently upwards.
Have a look and see what condition the pins are in, even though mine were clean I gave them a clean with contact cleaner which I also purchased from Maplins. The product code is N61AN.
I then connected the plug and removed it a couple of times which should be all you need to do with or without contact cleaner to remove any crud on the connectors.
I filled up the socket with the silicon dielectric grease and refitted the plug. I then removed the plug and filled up the socket again and refitted the plug.
I fired up the engine and went for a drive, I instantly noticed that the engine seemed slightly smoother between gear changes. As the van arrived at normal operating temperature I also noticed that one particular quirk of my van had disappeared. Normally if I rev my van as it returns to idle it sometimes stutters for a few seconds and then sorts its self out and idles smoothly. Now I can rev the van and it instantly returns to a smooth idle, it also seems a bit smoother in general. In my opinion adding the grease has definately made an improvement. This seems to concur with other peoples experience who have tried this on the Skoda and Tdiclub forums.
One thing this mod won’t do is cure a MAF which has failed.