whall

In early July I replaced the timing belt, WP, rebuilt the tensioner, etc. I then rechecked after 100, 500 miles and 1500 miles. About 2 weeks ago, the light came on after about 3 mins of driving. I checked and tension appears fine. Drove again and same thing. Now, most mornings at 3 minutes, the light goes on. When I start it during the day, no light. It is cooling a lot up here now over night and I have had the car in the drive-way as we are working on my son's Z-car. Any suggestions?
The wiring appears fine and this only happens overnight on fairly cold nights.

AO

Is there oil in the tensioner?

Schocki

How is the tension when the engine is really cold?

AO

Another question... did you check the tension after it sat for the night or after it had been run for a while?

It could be that as the engine cools and contracts you are getting just loose enough to trigger the warning system, but then later in the day (as the engine takes a long to to cool) the engine is sufficiently warm enough to no trigger the warning.

You might consider tightening the belt just a bit so it's on the upper side of the tension limits and see if the symptoms persist.

Bill Ball

If the tension is verified correct, then there is most likely a break in the sensor wiring. Likeliest spot is where the wire clips onto the spade connector on the top of tensioner arm. It tends to fall off or get rubbed off by the TB cover. Pull the tension sensor connector plug from the front of the center TB cover and test the ground continuity of the exposed lead in the cover. If there is no continuity, loosen the TB cover bolts and look behind the center cover at the spade I mentioned. If it is intact, then check the wire to the spade. If that is OK, then the rigid copper blade (later replaced with a flexible wire) that connects the spade to the base of the tensioner arm has cracked. Replacing this requires removal of the cover and that requires removal of a lot of other crap first.

If the lead in the TB cover has continuity with ground, then test the harness wire for same. If that has no continuity then there is a break in the harness (rare).

Bill51sdr

The 3 minute delay is a symptom of a fault in the circuit to the sensor. I would concentrate on that.

PorKen

A three minute delay is built into the Central Warning system.

I would like to figure out a way to make it immediate, IE bypass the CWS.

sharkmeister85

I thought the 3 minute delay was normal functioning.
(ed. Looks like Mr. Timing Guru beat me! )
Glenn

whall

Well, when I checked it, the engine was cooled down but not as cold as a Fall Evening in PG. As far as the oil in the tensioner, I checked it at the 1500 mile mark - about 2k miles ago and it was completely full. I know about the 3 minute delay but does it seem reasonable that temperature would have sufficient effect on either the tension or the electrical to cause this. The tension was near the upper limits of the Kempf tool when I last checked. Tonight, I think I will open it up and check the tensioner fluid and electrical again. I may just tighten the tension a slight amount as well.
It just seems very odd that it happens every morning when the evening got chilly (which is most evenings now) and then it can sit at my office all day and I start it at the end of the day and no light. Thanks for the input.

Bill Ball

Yes, the 3 minute delay is normal. If the system keeps tripping after 3 minutes despite good belt tension, then the tension sensor system itself probably has a continuity break.

AO

I suppose your Kempf tool could be off a bit... just another thought. (Sorry Jay)

Bill Ball

It probably has nothing to do with oil fill. That prevents overtensioning as the engine block expands when HOT. A hot engine INCREASES the tension, and would not trip the low tension warning. So, in your case and electrical break is what you need to be looking for.

Over a long period of time, a dry tensioner will overtension and stretch the belt, utlimately leading to it being loose when cold.

Also, don't run the tension higher because you think the sensor might be overly sensitive. I go mid-window on the Kempf gauge. Going to high wears out cam gears.

You have a fault and just have to find it. I have found the sensor wire connector to have popped off the tensioner arm spade in 3 cars that had symptoms just like yours. The spade connector was positioned such that the inside of the TB cover rubbed it and worked the connector off the spade. I loosened Allen head screw that held the spade to the arm and swung it around so it no longer made contact with the cover.

FlyingDog

It would have to be off by a hell of a lot. Set the tension correctly and ignore/disconnect/destroy the idiot light.

AO

Bill, I disagree with your assessment. The light comes on when the car is started after a long down period (I think sifficiently long that the oil in the tensioner has reverted to ambient temperature).

The light does not come on after a restart in the afternoon. This would indicate (to me) that the block has sufficiently transfered enough heat into the tensioner to increase the tension - thus no light. If the light came on regardless, then I would agree, but this little fact seems to indicate that his tension could be low.

Bill Ball

It's not the tool. He has an electrical fault. It should be easy to get the system to work properly. It saved my butt once when I had a bad belt.