WallyP

Recommended fluid is engine oil in the tensioners with the fill/bleed valves.

A trigger-type pump oil can and a piece of clear plastic hose is the easiest way to fill.

You put the oil in the top filler screw until it comes out of the bottom bleed screw with no air bubbles.

RichS 1986928

Ok, I filled the tensioner just like recommended.

No luck. Still got the T-belt warning this morning.

Is it possible that she's just running so rough in the morning that it's causing this problem?

Again, the tesioner was just rebuilt.

heinrich

not possible. when the light comes on, shut off, and check tension.

RichS 1986928

I think this has to do with the way I'm warming up the car in the morning. I start it and let
it sit with no throttle for up to 5 minutes every morning.
So if I understand the warning system correctly.. the warning will not activate until 3 minutes have
passed. So after 3+ minutes the car is running rough and triggers the warning. It seems to me that the delay is there to avoid false readings during a start up with may be rough because cold.

That's why when I start the car after work and leave in less than 3 minutes I get no warning... by
the time 3 minutes is up, I've already adjusted the 'rough idle problem' by warming it up with the
gas pedal.

The tension is correct, I don't need to check it again to see that.

I think I need to figure out how to stop the car from running so harsh in the cold mornings.. She's
in the garage now, but it's going to get colder.

But I'm surprised I haven't found anyone else having TB warnings when their engine runs rough.

John Veninger

That's because it should go on!
You need to remove the covers and check connection to the tensioner.

WallyP

Warming up an engine is no longer recommended - as soon as the engine will reliably move the car, drive away gently. Warming the engine further increases wear, emissions and oil contamination.

I second the motion to check and clean all of the connections on the wire between the tensioner and the warning computer. The most common problems include:
- The round connector in the timing belt cover (behind the dipstick).
- The flat 1/4" spade connector just inside the timing belt cover.
- The wire or strap on the tensioner arm.

RichS 1986928

Wally, Thanks for responding, I missed it earlier.

Can you explain why warming up the car is bad other than the fact that it's actually running for a longer period of time.

I'm going to try to change to to motor oil in the Tensioner. I'll let 928intl know that their T-belt service guide is recommending the wrong Tensioner oil. Do
you have any info to back this up?

I have checked all the connections to the Sensor. They look good. Again, this problem is not intermittent at all, hence I doubt it's a connector issue.

Thanks,
Rich

the flyin' scotsman

Temprature dependant...............we have days when we dare not shut engines off and when we do we 'plug' in the block to keep it warm.

Then again the 928 is toasty in the garage.

Bill Ball

The tensioner oil recommendation changed in the Service Tech guide for MY83 from gear oil to motor oil, but it is not 100% clear that this was a real change or a translation vagary. It really shouldn't matter.

Wally can expound on why warming up is not a good idea, but, the practice was long ago abandoned. Tolerances in modern motors are tighter such that warming doesn't accomplish anything other than waste fuel and time.

You definitely need to check the tension if you haven't already. There is a good chance it is borderline low. It should be in the upper part of the adjustment window on the Kemf gauge.

danglerb

Idling warms the engine slower, and the longer its cold the longer it is running under a richer than desirable fuel mixture and unburnt gasoline in the cylinder greatly increases wear by washing off the oil film.

How do you guys stand the tension of having a motor held together with a rubber band?

RichS 1986928

Bill, I've checked the tension several times, with the car cold and I followed all the instructions
including the tip about going to the tight side of the window on the kempf gauge.

From what I'm piecing together here, the motor oil vs. gear oil shouldn't matter that much.
So hopefully if I stop warming the car up for 5 - 10 minutes the warning will stop... I guess I'll
try that and recheck all the connections too.

Rich

928drvr86.5

Hi Rich,

Have you checked the tensioner ground wire continuity to the warning light? Since you have checked the tension already and know that it is good, i would suggest removing the Warning light wire from the front of the timing belt cover and puting a multimeter between the connection on the cover and the engine block to check continuity (ohms) of the tensioner arm ground. I would then start the car as you normally do and watch the meter closely during your warm-up time. The meter should always read close to 0 ohms if the tension is correct.

RichS 1986928

Thanks Ben, I will check that.

The main reason I doubt that this is a connector issue is the fact that this NEVER happens
when the motor is warm. It only happens after the car has been sitting and only when
it's less than 40 degrees F. And it's very consistent.

928drvr86.5

Rich,

If the ground continuity (0 ohms) stays steady thru-out the time when the light normally comes on it's most likely not a problem with your tensioner. If the tensioner ground checks out ok, your problem is likely to be in the brain or the wire running back from the belt cover. To check the brain and wire running to it you can jumper the wire you removed from the timing belt cover directly to a good ground. With the wire grounded the timing belt light should not come on (Ground is good tension). Obviously if the light continues to come on there is a problem with the brain or the wire going to it.