hlj821

I have a '91 S4 that recently had the timing belt service done, was driven on a few 100 mile trips, and retensioned. Now the toothed belt warning just constantly goes off, the sensor is fine and full. What would cause this and what will stop this warning? Help!!! Thanks in advance.

Tony

Some where the warning wire in the circuit is being interupted. Does it come on after the same amount of time has elapsed?

Since the light is on already, take the wire that leads into the tbelt cover where it connects and ground that wire on purpose. This way you can eliminate the fault being on the tensioner/system itself behind the cover. If it still comes on then its the wiring prior to that point.

Of course, check the tesnion to see if its off....but it seems that has already been done.

hlj821

Thanks Tony, btw, how are you doing. It's been a long time.

hlj821

Oh and it comes on after about 3 minites each time.

pcar928fan

Could simply be that the belt is not tight enough!

Do you know Joey V. down in the Valley? He lost his S4 to fire a 12 to 18 months ago. Good kid, I am sure he would love to know another shark fan down in that neck of the woods! Not a lot of 928's down there!

Tails

Need to re-check the tension and I would suggest that you also check the cam gears WYIT.

When the TB was changed was the tensioner overhauled and fitted with new "O" ring, boot etc?

As the warning comes up after 3 minutes the circuit is working as designed, however, for your information there is a test procedure for checking the circuit contained in Jim Moorehouse Technical CD in one of the technical notices.

Tails 1990 928S4 Auto

Mrmerlin

to check with an ohm meter remove the wire from the front of the timing cover then probe one to ground and one to the pin on the connector of the timing cover.
it should be grounded if not then the fault is within the timing cover,
either the wire has broken or the connector has come off the male pin or the belt is infact loose

the flyin' scotsman

Check the wire is in correct place. If the folks who did the replacement did not replace the wire properly it can vibrate off.

This wire completes the ground circuit which if not connected will cause the light to illuminate after a short period of time from engine start. The no light on immediately is by design.

WICruiser

The 3 minute delay is built into the circuit so it sounds like you have an open circuit all of the time just the light stays off for 3 minutes due to the timer circuit.

I had a similar problem and after checking the belt tension 3 times, and reviewing everything else at least twice I found the problem was the wire to cover terminal connection. After you check the belt tension, and confirm that the light stays out if the wire (removed from the cover) is connected to a good ground point, confirm that the terminal in the cover is showing zero resistance to ground (both static and with the engine running).

If all these are OK, then consider a means to tighten up the wire to cover terminal connection. I used a few strands of wopper wire from a 16 guage multi strand wire formed in a U shape to fit over the socket wire end of the wire terminal. The copper wire took up any clearance between the pin and the socket and also provided good electrical conductivity.

blown 87

Who did it and what did they do?
Some folks think that throwing a brand new Conti belt on a car and turning the adjuster up till it "feels" right, then the car is good for another 60-70 thousand miles.

Others, want to replace everything with new Porsche parts, tension with a 9201, retension at 1500 miles and replace the belt at 30,000 miles and look at every thing else while they are there, with a full inspection at 15,000 miles.

So there is a whole lot of middle ground there.

What ever the problem is, you need to find out before you do damage to the engine.

SeanR

I would have had the car back at the shop that did the work, and get it fixed asap.

WallyP

"I would have had the car back at the shop that did the work, and get it fixed asap."

Great idea - if the shop is as competent as you are. Unfortunately, there seems to be a good chance that all too many shops are so ignorant about the 928 that they would just crank down the tensioner, and when that didn't turn the light off, would finally figure out that they just needed to ground the wire to the warning computer.

I strongly feel that every owner should learn enough about the car to at least be able to tell when a shop is capable of properly maintaining and repairing a 928.

KewL928OwneR

Henry, I think the wire is faulty. Lets finally do a check on the car this weekend.

SeanR

Kewl, pull the cover off the passenger cam cover, reach in with your fingers and see if the spade connector on the tensioning arm is loose.

Bill Ball

Also, that little spade behind the cover can be oriented in different directions. I've seen the spade facing forward which caused contact with the inside of the belt cover, eventually knocking the wire connector off the spade. Loosen the tiny Allen and rotate the spade to the backside away from the cover.