Christopher Zach

Sean:

In reading this thread I ran into Post#4 which is as follows:

"Mine was fixed by adding oil to the tensioner but an hour into a drive it came back on when the oil leaked out, I have the rebuild parts just need the time. Personally I don't rev over 3k until the engine is fully warmed up, the belt is at its loosest when cold amongst other things. "

To date that's the only person that replied with "This same situation has happened to me, here is what it was". So this is a step to take in running down this problem.

What I see post #52 saying is this:
"You've already got the grommet pulled from the center cover so follow the wire to this spade. Remove the passenger gear cover for easy access."

Unhook it and ground it to the block and you can test your theory. If after 3 minutes the alarm doesn't go off then the system is working as it should. When you've completed that, start tearing down the front of the engine and find out why this issue is going in.

Ok, I can do that, however I spent this past weekend verifying if the belt was too tight and was going to (break my camshafts, stretch the belt to break internal cords, burn out the water pump, cause a gremlin to beat me with a rock, etc) because several people were arguing if I tested it at TDC. So I did, to make damn sure it was at zero on the crank pulley and at the cam tower. I didn't pull the head covers to verify the cams were pointing towards each other at the proper angle, but I'll let that go. They were, it was, and testing the belt right at the last tooth possible before going into the lower belt covers showed a centered pointer and what *should* be proper tension. Then a review of the tensioner wire, connection to the tensioner, etc, as you said to see if it was a loose or bad connection (yes, the connection was a bit dirty, yes I re-crimped the plug, cleaned the spade, checked to make sure it was intact, used Q-tips dipped in alcohol to clean everything, put it together, back to error-land).

My main concern is the belt will break and cause the usual 28 valve repair job that I have come to know and love.

If in your opinion (and I assume you know what you're talking about, having been in this type of engine more than I have) the issue is *not* the timing belt about to break and stretching in some strange and unusual way that I have not seen yet on this or the PP forums nor seems to either advance or retard the engine timing at higher power levels then pls say so and I'll stop freaking out about the belt.

So one step at a time. I'll check to see if the computer faults with the wire hard grounded, simple enough. Will you be at the Shark thing in Dulles, I'd like to say hi and buy you a root beer....

C

zekgb

Man you are making this way too hard. Either the warning circuit is bad (and there are really only two failure points for it, see my post at the beginning of the thread for troubleshooting advice from when I went through the same issue twice) or you have a mechanical issue that requires teardown/rebuild, period end of story.

Christopher Zach

Thanks Zek. I've just been going down the ole Porsche troubleshooting tree. Checking and topping off the oil tensioner is in there.....

Regardless, I tested the circuit by grounding it then driving around like a nut. No faults thrown. Shut down, plugged back in, faults at over 4500 RPM under load. Drove home, checked tensioner oil, added a bit just to remove any bubbles, checked, fault at over 4500 RPM under load.

Time to take it to the shop, pull the belt and replace. Running out of other things to check at this point. But I can say at this point I've pretty much been through everything (when your strap broke, did it trip only under heavy load or at random?)

On to the next problem.

Mrmerlin

CZ please reread post 51 and follow through,
If you do you will get a reliable answer to your issues.



your response is requested,
thanks,
MrMerlin

BTW your pictures will answer many questions that the people that are willing to assist you still have

Christopher Zach

My response is requested.... Formal....

Fair enough: I have spent the last hour reading every post in this thread. Based on the responses, the troubleshooting done so far, and some rather conflicting recommendations, the following axioms are in place as of 7:04am EDT, September 13th:

1) The belt is reading as properly tensioned at TDC.
2) The tensioner control system works and is tested.
3) The brass strap is intact, the connection points are cleaned
4) The tensioner is filled with oil.
5) All steps in troubleshooting tree Porsche 9010 have been completed

The event still happens.

Therefore the only remaining post to review is post 16. Given Greg's imprimatur I think he (and FredR for pointing this out in 17) is correct in his analysis.

Likewise FredR reiterated this in post #40. I have verified there is nothing wrong in the tensioner assembly or control, therefore the problem must be in the belt itself.

Going back to Gregg(post 17) he mentions that third party belts can stretch under load. This matches what I have seen in this car. Given that I do not know if this is a genuine Porsche belt or an aftermarket, we should assume an aftermarket.

I'm not taking the car apart again, or taking bunches of pictures for the interest of various people on the thread. Last time I did that it led to a divergent discussion on where TDC is.

The car will have the timing belt replaced by a professional shop that has the Porsche tensioning tool 90201 immediately. The Belt Ten light is telling me the belt is stretching at high RPMs/high loads, taking more pictures will not point that out.

Mrmerlin

thanks for the response,
based on your results and the lack of pictures the issue could be one of the following .
give this info to your mechanic for what to look for

A Disintegrating isolator collar, this is on the tensioner pin,
the pieces will fall into the piston well and cause erratic ground paths.

A fractured brass grounding strip

Damaged tensioner piston bore or incorrect bellville washer stack

List of Non conforming tensioner parts

IE a different arm to roller, or different tensioner body
A missing snap ring on the back of the tensioner roller

The spacer washer for the tensioner pin is missing or not the correct part, this adds tension to the spring.

The spring is damaged.

The tensioner pivot bushings are worn,

The pivot bolt is bent.

The water pump bearing is loose,

The cam pulleys are bent,

The belt has gotten oil or coolant on it and been damaged

Alan

Chris,
When changing the belt also change out the brass strip to the flexible wire version from the later cars.

Alan

zekgb

Sigh.

M. Requin

You indicated in your other thread on ABS/brake pad warning light issues that you have resolved this problem How? It might be useful to others for you to post the resolution here.

SteveG

"or taking bunches of pictures for the interest of various people on the thread. Last time I did that it led to a divergent discussion on where TDC is. "

I think that is not the attitude you intend, but as written this is not helpful to the people who have devoted time your issues. Posting pic and describing the issue(s) accurately points to the old "garbage in garbage out". It's pretty much a minimum when diagnosing the complicated procedures here. The advice is free; people are trying to help you. Or you can pay a mechanic to learn what is being offered here by people who are very knowledgeable.

Regards,

Christopher Zach

I will say that a few of the replies were not very helpful; if attitudes like a few people display on this forum are common then it helps me to understand why people in the greater public community stay away from these cars.

Car is running fine now, I will wait 2 weeks before posting the solution as I need to drive at least 500 miles then check again to make sure it is properly fixed and I would not want to confuse anyone with a false solution.

M. Requin

Completely reasonable. I like to wait before posting that "I fixed it" , or before I give a product evaluation, for just the same reason. Or sometimes I just perseverate. Mostly the former, I hope

Christopher Zach

Ok, it's been two weeks, time to post the resolution.

So I gave up and called my somewhat cranky German mechanic to have the timing belt fixed and the whole front end looked over. Explained the situation.

• How many miles are on ze belt? 35,000.
• Did you check the belt tension? Yes.
• Did you check the wire and the computer. Yes and yes.
• Did you retension the belt? Well, no.

Retention the belt, it is slightly loose.

But it looked good.

It is not good. Did you put pressure on the tool when testing it?

Well yes, I wanted to make sure it was against the wall.

No. Do it till it touches, then read ze tension. Then tension the belt. Half a turn of the bolt should do it.

So I went in, checked tension by setting to TDC, going to the bottom most slot in the belt, and moving the tool perpendicular to the belt till I heard the tink of it hitting the wall. On the low end but in the window. Hold it with some pressure and it's in the middle. Ok. Marked the bolt with a marker, loosened the jam nut, turned a bit over 1/2 a turn. Pointer is past the center towards the other end of the window. Tightened the jam nut, checked again, turned the engine over by hand, checked again, all good.

Closed up engine. No more light. Tested light by pulling plug, light comes on. So light works, tension was just a bit loose all the time.

My errors:
1) Testing one notch above the lower cam cover will give a false high reading.
2) Pressing on the tension testing tool can give a false high reading.

3) You don't need to turn the bolt much to adjust the tension.

Thoughts:
When I checked the belt I did note that it felt floppy. It did, and was. Once I tightened the tensioner it felt more "right" where right is more what the 944S feels like.

I'll check tension again at 2,500 miles then every 15k miles going forward. Have about 500 miles on belt now, no issues detected.

Coupled with fixing the ABS, brake pad lights, and tail lights I now have a car that throws no errors. Which reduces my stress by a lot.

Thanks everyone for the thoughts, see you all at the VA gathering this weekend.

C