Mongo

2 nights ago my friend and I took the S4 out for a cruise. We had the stereo blasting and we drove for about 30-40 min. on the freeway I put the pedal to the floor and the car downshifted....the belt tension light came on! I just put a belt in and its no older than 100 miles!!! Another thing too is we ONLY had the belt replaced because the Porsche mechanic said that everything else checked out and that the belt had only mild-moderate wear in there...Anyways...We pull over and i turn the car off and turn it on....all's fine...

after stopping by my uncles' house for a bit we head back and the timing belt light went on when the 928 kicked down to first at the stoplight on takeoff. when we came to the offramp from the freeway to get to my house i signaled right...and the blinker was flashing like a rice rocket's tweaker blinker...my friend said he had a 928 before with a problem like that and he pulled the faceplate off the stereo and everything was fine afterwards...

So i pulled over again...turned off the car completely and disconnected the faceplate off the Alpine CD head unit (I have a 4-channel amp connected to it) All was fine...but on a side note we ejected the CD and the CD was so hot it was glazed underneath ruining my brand new Swordfish Sountrack <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" /> No warning lights came on again and the turn signal was absolutely fine and I ran it pretty hard on the way home and got that motor to howl to 6000 rpm with no belt light....weeeeeeeeeeeeeeeeeiiiiiird...

My question is....I had this stereo for about a month and a half now...the guys at Circuit City where i work installed it. But whats weird was why was my CD so hot that it glazed, why did the belt tensioning light come on and why the hell was my turn signal tweaking???? Is this a voltage problem relating to the stereo? Could the amp and the Alpine not be compatible with the car like my friend says??? I HAD ABSOLUTELY NO PROBLEMS WHATSOEVER ON THE WAY HOME AFTER DISCONNECTING THE FACEPLATE.

help.... <img src="graemlins/crying.gif" border="0" alt="[crying]" />

NOTE: CAR IS RE-WIRED WITH MONSTER CABLE TO 6 SPEAKERS NOT INCLUDING 2 FRONT TWEETERS DUE TO A BYPASS. ALPINE HEAD UNIT IS MODEL CDE-7872, 4-CHANNEL AMP IS A V POWER 55 X 4 CHANNEL. ONLY THE FRONT DOOR SPEAKERS AND THE SPEAKERS RIGHT BEHIND THE DRIVER AND PASSENGER SEATS ARE AMPLIFIED IF THIS HELPS SOME....

replies are very appreciated and I will thankful for any help possible.

Donald

Chula Vista-
Check the stereo ground. That is likely to be the heating problem. Also better check to see where the installer pulled the power for all of that. It appears as if he pulled it out of a no-no circuit. The battery is always a good place from which to light up add-ons, and ground them back there as well (at the grounding strap).
Donald

P.S.
I assume that removing the faceplate shuts down the stereo, is that correct?

Nicole

I cannot comment on your monster stereo, but the timing belt light indicates that the belt has not been tensioned correctly. I had a similar problem with my first 928. The light only came on when the engine speed changed rapidly (e.g. at kickdown). It always stays on until restart. Tightening the belt made this go away.

I hear so many discussions about belt tension, and certain tricks and techniques to get it right. Make sure you have it done by a mechanic with extensive 928 experience. The PO of my curent 928 had the belt done by a Mercedes expert (after all, the 928 is the best MErcedes that Porsche ever built, right?). They screwed up big time, and I had to have everything redone before I could safely drive the car home.

Mongo

yup it does, and thanks for the tip. My father called and said there were no problems with it on the way to work..even with the stereo on and a full throttle take off and kickdown.

my guess is that the amp overheated cuz we turned up the treble and the base and the volume up pretty loud to test it. I think it overheated and caused a voltage problem, tripping the belt light and tweaking the turn signal...these cars are quite interesting...

Thom1

Hi Eurospec,

I would listen to Nicole. Otherwise, you could be in for a $6000 repair bill. I would get the Kempf belt tensioner tool, pull the right timing belt cover, and check the tension. Procedure is simple. Tension can be adjusted by a novice in an hour or two. See this link. We addressed belt issues. My ... Belt ... Essentials document has links to procedures. It is in the next to last response.

HTH,
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

Mike Schmidt

Another possibility for the belt tension warning light coming on is a bad or corroded connection at the sensor. Apparently this is kind of common and will cause false warnings. The vibration and movement from full throttle blasts can cause the false warnings if that's a questionable connection there at the sensor. Do not assume this is the problem though. Check the belt tension first. If that's okay, check the connections for the sensor wiring.

Mongo

thanks everyone, the timing belt is about a week old now. I'm gonna make arrangements tomorrow to get a retension on the new belt. Hopefully i won't get anymore warnings...

Jay Wellwood

Uhhhhhh.....something else to point out here.

When replacing the Tbelt - the water pump should always be replaced as well.

Scott at SITM's water pump failed last weekend. Apparently the Tbelt had been replaced ~32K miles ago, but no indication that the water pump was also replaced. For peace of mind (and a healthy Shark) always replace the weater pump when you replace the Tbelt.

<img src="graemlins/nono.gif" border="0" alt="[nono]" />

WallyP

Another thing that should be checked - The tensioner should be rebuilt (cleaned, checked, new boot, refilled with oil) every time that the belt is changed. The oil in the tensioner acts as a heat transfer medium, lubricates the tensioner, and acts as a dampener for the belt fluctuations.

No oil can cause the light to come on. The boot gets old, cracks, and lets the oil out.

There are two bleed screws on the S4 tensioner - put oil in the top one until it comes out of the bottom one (yep - pu it in the top one). If the oil leaks out, the tensioner boot neeeds replacing.

Shane

Wally,

Does that little trick work for the MY 86?

WallyP

Yes - I should have been more precise and said on all 32-valve engines.

The earlier 16-valve tensioners also need to be filled with oil, but may not have the bleed screws. They are filled with oil during assembly.
The oil in the 32-valve tensioners is actually partially in the tensioner and partially in a recess in the block, for better heat transfer to the bi-metallic Belleville washers that maintain the tension.

Shane

Thanks Wally!!

I'll be able to do a little more by myself once the manuals get here. Hopefully before I head to Washington. But by being a mechanic most things will come naturally to me. Of course a 12cyl. O.P. Fairbanks Morse Diesel Engine with 3800 H.P. is just a little different. Especially since we converted them to run on Fish Oil. <img src="graemlins/a_smil17.gif" border="0" alt="[blabla]" />