Went to do the DISA rebuild

And the electrical connector was not fully clipped on. It lifted off easily without having to squeeze the metal clip.

This made me think that it had already been replaced or rebuilt and the mechanic didn’t fully seat the connector. Plus looking closely at the top Torx bolt I could see that the star shape was a bit boogered up. Also I could see some grease on the (O-ring seal ?) as I looked down from the top with a flashlight. So I left it alone assuming it had been replaced or rebuilt.

My question, being that the connector was basically just sitting on the plug and not snapped in, I assume it was making contact, the car runs fine. What would the symptoms be if the plug were not making contact?

I guess I could totally unplug it and take it for a ride but I don’t really feel comfortable doing that.

If the plug was not making contact, then the DISA would not have been functioning. The usual symptoms are things like rough idle, flat/dull spot in the rev band, fuel consumption etc though from my personal experience, hard to "feel" in your situation if you've driven with it off/non-functional since ownership.

I rebuilt mine for peace of mind and was surprised by the night and day change after... you don't know what you don't know!

I don't think going for a drive with it off will hurt anything - plenty of people (myself included) drove around with non functioning DISA valves... hence the rebuilds :rofl: !

It's really not a big deal to take the DISA off and check it out. With the airbox out, its honestly just a few torx screws.

tomrdy said:

If the plug was not making contact, then the DISA would not have been functioning. The usual symptoms are things like rough idle, flat/dull spot in the rev band, fuel consumption etc though from my personal experience, hard to "feel" in your situation if you've driven with it off/non-functional since ownership.

I rebuilt mine for peace of mind and was surprised by the night and day change after... you don't know what you don't know!

I don't think going for a drive with it off will hurt anything - plenty of people (myself included) drove around with non functioning DISA valves... hence the rebuilds :rofl: !

It's really not a big deal to take the DISA off and check it out. With the airbox out, its honestly just a few torx screws.

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Thanks for the reply. The car does get pretty good gas mileage, in the 25-26 MPG range so I’m guessing the plug was making contact.

I guess it couldn’t hurt to pull the DISA and give it a quick look, I do have a German Auto Solutions rebuild kit. But not experiencing any symptoms I don’t see any reason to hurry and from the things I mentioned in my post I do think it had been replaced.

It had 2 previous owners. The original owner was a heart surgeons wife and the second a multi BMW owner and enthusiast. Both owners who you would think would keep up on maintenance. All appearances suggest the car was well maintained. Anyone can forget to fully seat a plug I suppose and that was my biggest reason to think it had been replaced or else why would the plug have been removed in the first place...

I just got back from my garage. I pulled the DISA and I was right, it had been replaced, it is a Viaco brand (the name is on the back, you can’t see it until you remove the unit) and it looks fine. I was nervous reading the horror stories about the pin backing out and being sucked into the engine. Now at least I know the pin is in place and hopefully Viaco is a reliable brand I can trust. They sell that brand on Pelican Parts for $267 USD.

From what I’ve read, a failing DISA gives ample warning that it is going bad. What I like about the rebuild kit is that there is no possible way that the pin can back out. I’m going to contact GAS and see if their kit works on aftermarket DISAs.