Colorado964turbo

OK folks, this one has me stumped.

At 2,400 RPM up until right before 3,000 rpm, I have a loud clicking sound coming from under the dash to the left (I think, its tough to trouble shoot the exact location moving). It doesn't matter if I am moving, or sitting stopped and revving it. It literally just starts clicking away right at 2,400 rpm and stops when I get over 3,000 rpm.

I've looked under the dash and there appear to be a couple of relays down there, along with the big silver control box that monitors all of the electrical signals and what not. I've looked through the Porsche 911 Enthusuast's Companion and can't really find anything that would be causing the sound.

Have any of you run into this problem in the past?

I know there are some relays under the seat and the turbo control unit. Could something assosciated with that be causing the problem? I am thinking it has to be engine speed related, since I only hear at it, yep I'll say it one more time 2,400 rpm.

Hopefully this is easy to diagnoze and I am just overlooking something.

Thanks guys / gals (although I think most women are in the OT and 944 forums, smile).

Bill

Staffan

Never heard of this.

Perhaps you can be more precise with the location since you can replicate it standing still?

Don't recall any relays under the seat, but I could be wrong.

SA Mike

Does it come back when you back down to 2,400. When I first start mine there is a faint ticking noise, but doesn't last more that 5 seconds.

Colorado964turbo

After laying on my back for a while under teh steering wheel (yeah thats fun), I started the car up with my wife watching the tach, and I couldn't get it to replicate the sound.

Mike, it starts right at 2,400 rpm and slows down as I reach 3,000 rpm. If i left of the gas slowly, it starts clicking again as the engine speed drops, at the same rpm range as going up.

As driving at sane speeds is done under 3000 rpm on the highway, its quite irritating.

SA Mike

It's probably not the same noise I'm hearing. Mine quits after around 5 seconds and is not RPM related

Colorado964turbo

Hmm, yeah mine is not coming from the engine, but somewhere down low behind the dash...

kleinbbc2

What about the heater/ AC flap. I think thats down by your left foot .It could be having you think its the dash. Just a guess

911addict

Not resonance, only at particular revs?

Colorado964turbo

It sounds electrical, not something rattling, and comes on exactly at 2,400 rpm. Now with that being said. I did do some poking around down there, and afterwards I started it and it wouldn't make the noise. I think I am going to take it for a spin around the neighborhood tonight and see if I can get it to replicate the clicking. It definitley sounds electrical.

Colorado964turbo

OK guys, I found the source of the sound. Its part number 965.618.130.00, its listed as "Multifunction Control Unit", and its a whopping $731. It is located under the seat, and right next to the Control Unit, Acceleration Enrichment device (965.618.131.00). The Acceleration Enrichment Device has %'s listed on it for different pins. They look pretty dang similar, and only are different by the part number.

After reading up on the part in Adrian's book, I think it might be the Turbocharger control unit (page 165 in the book). It controls a bunch of stuff, including the overboost pressure saftey circuit. Which could explain why sometimes the overboost safety kicks in, and sometimes it doesn't. When it makes the clicking sound, you can actually feel it.

Do any of you know of a way to test this part? Its a special order non-returnable part of course.

Thanks!

Bill

dholling13

Man, I wonder if any efi car owners have one they would part with.

Or....

If 964 turbo owner loot in Colorado is listening, maybe he could lend you his to test while he's pulling his engine?

Turbohead

Bill,
I have that part if you need it email me.It is the turbocharger control.
Elliot

nathanUK '81 930 G50

Maybe your wastegate is at fault?

Colorado964turbo

I thought that too Nathan, but the wastegate is checking out ok.

THanks Elliott.

nathanUK '81 930 G50

Didn't want you to buy an expensive electric box if it was just a mix up with a hose connection.