When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Christopher, you are trying to solve mechanical/electrical issues with the internet. That is not going to work, ever.
The connector is a pin-and-socket affair, with an o-ring. You pulled out the receptacle along with the connector. That may or may not be part of the problem, you won't know until you get the covers off.
An "SCR" is a power-control device, the alarm signal is simply latched (i.e. "remembered") by the alarm controller until you power off and restart the motor. Then there is a new 3-minute delay until there is a momentary loss-of-contact. It may be a loose connection, but it seems more likely that there is a belt issue.
The fact that your alarm is recurring is a strong indication that something is wrong mechanically. The longer you mess around with it, the greater likelihood that whatever is wrong will come apart altogether and bite you.
The advice here is all good, and Sean's is 100% on point: Quit screwing around and take it apart. Not the whole car, just the front of the engine. It's not a big deal, work carefully and post pictures. Your suggestion-- that "12 out of 16 valves bent per side" would at least confirm the problem-- is frankly absurd. It is far simpler to remove the covers and refresh the worn parts.
The connector is a pin-and-socket affair, with an o-ring. You pulled out the receptacle along with the connector. That may or may not be part of the problem, you won't know until you get the covers off.
Ok. Is there a picture of the pin and socket I can reference?
An "SCR" is a power-control device, the alarm signal is simply latched (i.e. "remembered") by the alarm controller until you power off and restart the motor. Then there is a new 3-minute delay until there is a momentary loss-of-contact. It may be a loose connection, but it seems more likely that there is a belt issue.
Sure. Easiest way to do this with 80's tech would be an SCR, sets the alarm regardless of if it the trigger event goes away or not, resets when power is removed. I would guess that they could do a 3 minute timer with a simple 555 circuit set to ground the line by default for 180 seconds, then allow the line to float based on a pull-up and of course the tensioner holding it down.
If anyone has a schematic of the whole alarm module that would be interesting, but I'm used to having to reverse engineer this kind of stuff.
The fact that your alarm is recurring is a strong indication that something is wrong mechanically. The longer you mess around with it, the greater likelihood that whatever is wrong will come apart altogether and bite you.
Something is odd, no doubt but I'm trying really hard to isolate the problem and change as few things as possible at once. The plug coming out is interesting, I would like to figure out how to disconnect it so I can test the controller and make sure it's not opening anywhere else. Remember this car has odd electrical gremlins that already bit me on the tail light and the headlights (hint: If the fuse for the headlight motor is loose or blows, the headlights cannot come on even if you crank them up. That was a week worth of pulling hairs).
The advice here is all good, and Sean's is 100% on point: Quit screwing around and take it apart. Not the whole car, just the front of the engine. It's not a big deal, work carefully and post pictures
Taking it apart and replacing lots of parts is no guarantee I will find the problem (been there in Porsche Land, done that, need to think this through). It's equally possible I could screw something else up while trying to chase down this problem.
This car is doing something that so far only one other person has seen anything like it, and that was decellerating from 140mph if I recall correctly (note: I am not decellerating from 140mph). The belt is only got ~30k miles, was replaced with all pulleys, tensioner rebuild, idlers, and water pump, and this shouldn't be happening. But it is.
I'll be taking the covers off this weekend to check the tension again and to reveal the tensioner mechanism. In the meantime I have re-routed the spark plug wires away from the sense line by fastening down the plug wire spreaders properly. I did have a problem years ago on another car where the plug wires were routed over the hall senders for a knock detector and the car did weird things at full RPMs. Strange stuff happens....
I was wondering if I would have to remove the mechanical fan and any other accessories to get that far; do you know if I would need to do that?
This will be figured out. One step at a time.
PS: Blowing the valves would be positive confirmation.
I know I said that with a smile, but in some ways at least you know what you're dealing with. And in my cases, time 1 was due to a Porsche installed -00 belt installed at the dealer when they had .01 and .02 belts out and time 2 was due to a chain ramp nylon rider breaking which at the time no one had ever heard of because no one had 200k miles on their engine. Live and learn, I got very good at replacing valves :-)
Ok. Is there a picture of the pin and socket I can reference?
The socket is #52 below, from PET. The connector is part of the wire harness, not readily available separately. Treat it gently. The socket is a snap-fit into the plastic center-cover, and the pigtail connects to contact #53. To disconnect the connector, gently pry both sides against the flange on the socket while releasing the clip. There is an o-ring on the connector to seal the contacts, and a locking clip.
It will all make sense once you are in there, or find any of the numerous how-to guides posted here.
Thank you, that makes more sense than images with what looks like a sliding spade to connect the wire to the outside world. That said, my connection seems pretty stuck, if it is designed to rotate I might have to hit it with contact cleaner to get it to un-connect.
CZ tell you what,
take it all apart,
take some quality pictures,
post them,
and you will have proper diagnosis on what you need to replace.
NOTE based on the sensor connection point,
you will need that part,
but you may also need the flat washer on the tensioner,
or the guide bushing on the pin.
and or the pivot bushings
As Mr Sean suggested take it apart,
inspect what you have ,
replace the worn parts,
put it back together ,
then you can drive the car for a long time with no worry.
NOTE Trying to do the least amount possible so the car will run will eventually ruin your driving experience and joy of ownership.
Trust me, there is more than one person that's encountered this issue and it almost always goes back to bad parts.
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.
Trust me, there is more than one person that's encountered this issue and it almost always goes back to bad parts.
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.
And if you have that kind of connector (flat sheet) replace it with a braided Insulated wire connector.
So it's been a few weeks and I had some time Sunday to re-check the car. This time I left it all night (65f) then took off the cover and had another look at the belt.
Belt still looks ok, took the engine around till it was at TDC as referenced on the cam *and* the flywheel (0 is TDC with the pointer pointing at it) and re-checked the tension with the Kempf tool.
Right on the money. In between the window, no problem. I was wondering how I got the slightly high message so I moved it one cam belt tooth up. Sure enough, reads slightly high (edge of window). Interesting that it is that sensitive to belt position, but this time I got it right at the bottom.
Then checked the tensioner. Looks ok, but the plug was a bit dirty. Pulled the plug, noticed the keeper is cracked on it, cleaned it up, cleaned up the connector and the tab on the tensioner with 91% isopropyl alcohol, put everything together, noted that you can get to the tensioner oil plugs without taking off the center cam cover, closed it up, ensured a tight fit for all connections, and fired up the motor.
Sure enough, go over 4500 RPM and light comes on. Shut down, curse a bit.
So we're down to only three possibilities:
1) Tension testing tool is bad. I will say the belt felt a bit floppy at cold at TDC. Less tension than I would put on an alternator belt, but the Kempf tool reads clean.
2) Belt is seriously defective. Maybe it's bad inside and passes the twist test but not a normal running at high RPMs.
3) Tensioner is low on oil. I'll give this a try, I think it's 85 weight gear oil; I'll fill it next weekend and see if it still is happening.
If it is, I'm taking it in for a full timing belt service.
Still need to figure out why the brake pad warning light comes on and the tail light warning light is so twitchy. But this is consistent enough (comes on only at 4500+ under load) and the connections are good enough that I no longer think this is a false positive.
Indeed this is the only path - we aren't talking of a total tear down - just look at what is giving you grief.
Originally Posted by Christopher Zach
Sure. Easiest way to do this with 80's tech would be an SCR, sets the alarm regardless of if it the trigger event goes away or not, resets when power is removed. I would guess that they could do a 3 minute timer with a simple 555 circuit set to ground the line by default for 180 seconds, then allow the line to float based on a pull-up and of course the tensioner holding it down.
If anyone has a schematic of the whole alarm module that would be interesting, but I'm used to having to reverse engineer this kind of stuff.
You have to stop thinking like this... you don't need to rebuild the alarm system or even understand it in detail - that's just nuts. You can test it doesn't create false positives of its own by just grounding the connector and waiting 3 minutes then maybe 10 more - (if you must - run the engine at 4500 RPM - There still won't be any alarm). Then you can open the connection and get an immediate alarm which will confirm that it detects correctly. You wont ever need to do more than this to gain confidence in it.
If I were you I wouldn't be running the car till I knew everything was OK.
BTW no engineer would ever use an SCR for this function - its not what an SCR is designed for (not even close). Don't try to re-engineer your car - at least not until you have it all working perfectly. Then you will probably find you won't want to (at least not very often), unless you are me
Indeed this is the only path - we aren't talking of a total tear down - just look at what is giving you grief.
That's what I've been doing. There's only two possibilities, either it's a problem with the belt itself, a problem with the tensioner, or it's a problem with the system telling me there is a problem with the belt.
I spent two weekends ago taking the car apart to check the tension, it looked fine (a bit high). Got nothing but complaints from some people that I don't know where TDC is from a hole in the wall. So this weekend I tore it down, looked at the tensioner, checked the timing belt *again* and it's right on the money, my error last time was checking the belt one tooth gap too high. So according to the tool, the tension at rest (which is what Porsche and probably every mechanic on the planet test to) is fine.
Likewise the tensioner appeared fine, no oil or grease stains or ripped boot or other issues there. Cleaned off the tab, crimped down the connector, snugged up the round circular socket on the tensioner plug, put everything together again, fired it up and it still faults.
So there are only three options left, either the belt is a magical belt that stretches while running, the tensioner is low on oil and is not doing the dampening action, or the computer brain is stupid and throwing false positives. At this point I do not think it's the computer, so I am ruling that out. The oil level in the tensioner I can check the next time I'm in there, if that's not it I'm taking it in to have the belt professionally replaced. If it still happens then it's the computer or I have a subtle crack in a cam shaft that only manifests itself at high RPMs or something.
I do appreciate the seemingly Sean-endless "tear everything apart" option, but to be honest that can result in more problems being created than fixed. Nor am I planning on building a new computer system. But I will take this step by step, eventually I'll either find the problem or I'll have a lot of parts to sell on Ebay :-)
So then test the tensioner warning system (positive & negative proofs) - its easy to do as I described. I think it is extremely unlikely to be the problem - but you can eliminate it from consideration pretty easily. Knock them off 1 by 1.
So then test the tensioner warning system (positive & negative proofs) - its easy to do as I described. I think it is extremely unlikely to be the problem - but you can eliminate it from consideration pretty easily. Knock them off 1 by 1.
Alan
At this point I agree, the warning system aft of the tensioner is probably not the issue. I thought about testing it this morning but realized that if the connections are all clean and good it was highly unlikely that this was the problem. Also I would have to take the car on the road to duplicate the error, as simply gunning the engine up to 5000/6000 does not light the indicator light. So I'd need a jack to plug the sense wire into, etc and go running around town resetting fault lights (the ABS and the brake sensors are also faulting, I think they're related to degraded connections at the inside the engine compartment plugs, but that's a later problem). Thus I need to get out the calipers to measure the jack pin's inside and outside diameter, then go to Digi-Key to buy a jack I can wire to hard ground to do a running test, then wait around for the parts to arrive, etc.....
Thus the next step: Check and ensure the tensioner is full. No one has really answered this, but maybe without the dampening function of the tensioner oil the tensioner arm bumps around enough to set off the alarm. Taking things apart today pointed out that this is easier than I thought to do: The belt covers do not need to come off, all I need is some brake cleaner to clean off the usual gunk from the nipples, then an 8mm wrench to open each valve while hooking a tube with 85 weight gear oil on the lower, and the mitey-vac on the upper. Pump a vacuum, till I see oil in the top tube.
Simple, just requires yet another weekend of fun filth in the engine room....
Post 52 and what Alans been saying gave you the details you needed to test the tension warning system.
Adding oil to the tensioner is going to do absolutely nothing to solve the issue you are having.
If your belt were defective, it would not longer be doing its job.
You are not listening to everyone who's been telling you what will fix your issue. You may not have noticed but some of these people have been doing this for a very, very long time so it might be in your best interests to listen. Some people will give up trying to help you in the future when its seen that you don't pay attention to what's being typed out to you.
08-28-2017, 08:07 PM
