Tensioner Light on dash is on
04-28-2010, 02:31 PM
#16
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Just adjusting the belt tension is not the right answer.
No matter what the problem is, adjusting the tension is not the right answer.
There are only three times when you should adjust the tension in the stock system: 1: During installation of a new belt. 2: About 1500 miles after you install a new belt. 3: After any service that required you to remove the belt.
If at any other time your tension is not right, something else is wrong. It could be the pivot arm shoulder bolt, it could be the belt stretching, it could be the WP eating the block or some other WP failure mode, there are several) but whatever the reason, DO NOT RE-TENSION a belt that has been in there for an unknown period of time.
If you do, you will cause stress on some other weakpoint (either the water pump pulley or the pivot arm shoulder bolt) and that will lead to catastrophic failure of the timing belt.
Please don't go in there with the intention of 'just tightening it up'. Presumably the belt was right at some point. If the belt has stretched, it's crap and you need a new one (and a rebuilt tensioner while you're in there at the least). If some other component is failing and causing the system to trigger then you need to fix that. Tightening the tensioner will only cause it to fail sooner.
It's also possible that your tensioner is out of oil, so that needs to be checked as well.
I have to say, it's not actually sounding like a typical warning light after all.
As some have said, when you switch the key on, all warning lights on the dash should come on, then once it's running they should all go out except the brake light, which will go out when you tap the brakes. If you're referring to the (!) button/light on the dash, that's something different. The belt tension indicator has a 2 minute (or so) delay after initial start up, so if it's on during that time, it's not the tensioner system, but something else, possibly something to do with the warning brain(?).
Easiest way to check is find the wire lead coming off of the engine wiring harness that leads to the little plug on the front of the center timing cover and meter that to ground (car turned off). If it's a good solid closed circuit (.000 ohms), then the tensioner is working. If you have a partial open or completely open circuit, the tensioner is triggered, but you need to find out why the belt is loose, not just tighten it.
If the tensioner circuit shows that it's good at this point with a good solid ground, you can start the car. If you unplug this while the car is running (after the initial 2 minutes) and the warning light on the dash goes on, then the indicator system is working.
Still not sure about the mode where the light stays on after startup...
Weird.
No matter what the problem is, adjusting the tension is not the right answer.
There are only three times when you should adjust the tension in the stock system: 1: During installation of a new belt. 2: About 1500 miles after you install a new belt. 3: After any service that required you to remove the belt.
If at any other time your tension is not right, something else is wrong. It could be the pivot arm shoulder bolt, it could be the belt stretching, it could be the WP eating the block or some other WP failure mode, there are several) but whatever the reason, DO NOT RE-TENSION a belt that has been in there for an unknown period of time.
If you do, you will cause stress on some other weakpoint (either the water pump pulley or the pivot arm shoulder bolt) and that will lead to catastrophic failure of the timing belt.
Please don't go in there with the intention of 'just tightening it up'. Presumably the belt was right at some point. If the belt has stretched, it's crap and you need a new one (and a rebuilt tensioner while you're in there at the least). If some other component is failing and causing the system to trigger then you need to fix that. Tightening the tensioner will only cause it to fail sooner.
It's also possible that your tensioner is out of oil, so that needs to be checked as well.
I have to say, it's not actually sounding like a typical warning light after all.
As some have said, when you switch the key on, all warning lights on the dash should come on, then once it's running they should all go out except the brake light, which will go out when you tap the brakes. If you're referring to the (!) button/light on the dash, that's something different. The belt tension indicator has a 2 minute (or so) delay after initial start up, so if it's on during that time, it's not the tensioner system, but something else, possibly something to do with the warning brain(?).
Easiest way to check is find the wire lead coming off of the engine wiring harness that leads to the little plug on the front of the center timing cover and meter that to ground (car turned off). If it's a good solid closed circuit (.000 ohms), then the tensioner is working. If you have a partial open or completely open circuit, the tensioner is triggered, but you need to find out why the belt is loose, not just tighten it.
If the tensioner circuit shows that it's good at this point with a good solid ground, you can start the car. If you unplug this while the car is running (after the initial 2 minutes) and the warning light on the dash goes on, then the indicator system is working.
Still not sure about the mode where the light stays on after startup...
Weird.
04-28-2010, 03:20 PM
#17
Rennlist Member
Its really so much more safe and appropriate on these crazy cars to take the time and spend the money to establish an excellent situation under those timing covers!
Not really a hard job, either, if you have some mechanical inclination.
Not really a hard job, either, if you have some mechanical inclination.
04-28-2010, 03:46 PM
#18
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Mine came on occasionally when I floored it getting up to speed on to a freeway (motorway here) from the service station exit. First time, I had the belt, pulleys and tensioners, and pump changed only to find the old belt was nearly new. Its happened twice since. Very weird.
04-28-2010, 09:51 PM
#21
Real life expericence from 86 S owner in the US.
Car was rounding into form after extensive freshening by one of the best 928 techs, ever. "Belt ten" light would illuminate when accelerating at full throttle - the anti-tailgating feature standard on all 928s.
The light would de-illuminate after stop-start on the engine or about 1 mile at under 2,500 rpm.
Many calls, e-mails, etc etc with the shop.
Long story short - the tensioner had gone into kind of a "safe mode". It needed to be rebuilt but wasn't about to let go and allow the valves to flog on the top of the pistons, either. OP's question seems very similar to this.
Having observed the Porkensioner-vs.stock cage match earlier this year, I won't recommend one over the other. I had the factory part rebuilt and it performs well, BUT IT REQUIRES MONITORING AND MAINTENANCE, especially the oil level in the tensioner. Chose one or the other but go all in - ALL the parts, ALL the monitoring, ALL the maintenance that is required for ALL of the benefits of the Ferry Porsche solution or the P'K-er.
Don't panic, but don't wait forever.
Car was rounding into form after extensive freshening by one of the best 928 techs, ever. "Belt ten" light would illuminate when accelerating at full throttle - the anti-tailgating feature standard on all 928s.
The light would de-illuminate after stop-start on the engine or about 1 mile at under 2,500 rpm.
Many calls, e-mails, etc etc with the shop.
Long story short - the tensioner had gone into kind of a "safe mode". It needed to be rebuilt but wasn't about to let go and allow the valves to flog on the top of the pistons, either. OP's question seems very similar to this.
Having observed the Porkensioner-vs.stock cage match earlier this year, I won't recommend one over the other. I had the factory part rebuilt and it performs well, BUT IT REQUIRES MONITORING AND MAINTENANCE, especially the oil level in the tensioner. Chose one or the other but go all in - ALL the parts, ALL the monitoring, ALL the maintenance that is required for ALL of the benefits of the Ferry Porsche solution or the P'K-er.
Don't panic, but don't wait forever.
05-02-2010, 01:21 AM
#22
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Real life expericence from 86 S owner in the US.
Car was rounding into form after extensive freshening by one of the best 928 techs, ever. "Belt ten" light would illuminate when accelerating at full throttle - the anti-tailgating feature standard on all 928s.
The light would de-illuminate after stop-start on the engine or about 1 mile at under 2,500 rpm.
Many calls, e-mails, etc etc with the shop.
Long story short - the tensioner had gone into kind of a "safe mode". It needed to be rebuilt but wasn't about to let go and allow the valves to flog on the top of the pistons, either. OP's question seems very similar to this.
Having observed the Porkensioner-vs.stock cage match earlier this year, I won't recommend one over the other. I had the factory part rebuilt and it performs well, BUT IT REQUIRES MONITORING AND MAINTENANCE, especially the oil level in the tensioner. Chose one or the other but go all in - ALL the parts, ALL the monitoring, ALL the maintenance that is required for ALL of the benefits of the Ferry Porsche solution or the P'K-er.
Don't panic, but don't wait forever.
Car was rounding into form after extensive freshening by one of the best 928 techs, ever. "Belt ten" light would illuminate when accelerating at full throttle - the anti-tailgating feature standard on all 928s.
The light would de-illuminate after stop-start on the engine or about 1 mile at under 2,500 rpm.
Many calls, e-mails, etc etc with the shop.
Long story short - the tensioner had gone into kind of a "safe mode". It needed to be rebuilt but wasn't about to let go and allow the valves to flog on the top of the pistons, either. OP's question seems very similar to this.
Having observed the Porkensioner-vs.stock cage match earlier this year, I won't recommend one over the other. I had the factory part rebuilt and it performs well, BUT IT REQUIRES MONITORING AND MAINTENANCE, especially the oil level in the tensioner. Chose one or the other but go all in - ALL the parts, ALL the monitoring, ALL the maintenance that is required for ALL of the benefits of the Ferry Porsche solution or the P'K-er.
Don't panic, but don't wait forever.
