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Posting this up because it took me some time to gather up this info. Hope that it's helpful to have all in once place and will save time for somebody else.
The original 964 knock, CHT, and reference sensors seem to be intermittently available. The alternatives are superseded 993/996 sensors which require an updated connector. Here is a 993/996 CHT male and female connector and the original 964 connectors (actually, the female 964 side is not quite identical to the original).
Currently, I was able to get an original knock sensor and CHT sensor, but only the superseded 993/996 reference/flywheel sensor was only available. I believe that the Porsche will now only sell you the updated 993/996 sensors.
New version problem #1.
The updated sensors are much shorter and they don't fit very well. Some rough measurements:
- Knock sensor leads: 47cm original 964, 32cm updated 993/996.
- Flywheel/reference sensor leads: 72cm original 964, 46cm updated 993/996.
- CHT sensor leads: 57cm original 964, 37cm updated 993/996.
For example, want to keep the original wire clip routing of your CHT sensor? Not going to happen with the shorter update version. You would need to pull the lead straight up through the engine tin grommet.
Can you see how stretched the update knock sensor cable is to reach the connector? (Hint, green connectors).
PIC6
New version problem #2
To update to the 993/996 sensors, you have to hack into your wiring harness and also update the connectors. A much better solution is to make up an adapter that mates the updated sensor connector to the original 964 wiring harness. No hacking and you get your wire length back. More on that below. Take a look, Porsche dealership electric tape, and Porsche dealership silicone glue. I even have the PO's 2005 receipt for this work. Wonderful.
Amp connectors, aka, Junior Power Timer. These are the plastic connectors
all over the engine wiring harness. Not only could your friendly Porsche dealer
have updated them, but they can also get brittle with age and can crack.
There are a suprising number of subtle variations for these little connectors.
Here are some part numbers for the 2 and 3 pole/pin/post connectors:
3-pos female connectors:
1-827578-1 Black AVAILABLE
1-827578-2 Grey N/A
1-827578-3 White N/A
1-827578-4 Green N/A
Data sheet, info, engineering drawings: http://www.te.com/catalog/pn/en/1-827578-1
2-pos female connectors:
1-827551-3 Black AVAILABLE
1-827551-4 Brown AVIALABLE
1-827551-5 Blue N/A
1-827551-6 Green N/A
1-827551-7 Red N/A
1-827551-8 Yellow AVAILABLE
Data sheet, info, engineering drawings: http://www.te.com/catalog/pn/en/827551-3
The 2 and 3 pos black connectors are available easily and cheaply. You can find where to get them by searching www.octopart.com for the part numbers. The N/A colors listed above are pretty much gone from the planet if you want them new.
There are a few variation of these Amp junior power timer connectors. Some have square metal release springs, other are more rounded, some have an extended wire/support end. But all of them will plug into each other. The differences aren't much more than cosmetic.
To be complete, here are a few Porsche part numbers for the updated connectors. I'm not sure what other makes use these, or what their generic part numbers are.
999.650.157.40 white cht housing
999.650.156.40 green knock housing
999.652.916.40 black reference/flywheel housing
So what if you *really* want an original and correct connector?
1. Chop it off of the harness from a salvaged car. You might find a 1980's 944 harness that you can cut up. Or someone's fried and burned old harness.
2. You try to get as close as original as possible.
I found a very close, white, 3pos, female housing to repair the CHT connector on my harness. I don't know where these guys are getting them from, but http://stores.ebay.co.uk/3-Way-Components/ have them, complete with pins and a new rubber boot too. It comes in a Bosch package, p/n 1284485120.
The difference is in the spring metal release wire. The original is straight and square shaped. The Bosch connector's is rounded and the housing is angled near the top of the wire.
Replacing it was easy enough. I took a grinding wheel to one of those $.10 jeweler's screwdrivers and made it small enough to slide inside the connector housing to release the retaining wings on the pins. You can see the metal tabs/wings on the pins that you have to press down before they will release from the housing.
It takes some wiggling, but eventually the pins will slip out. For the CHT, the #1 slot is black/brown wire, #2 slot is empty, and #3 slot is the brown wire.
Put a new rubber boot on first. Then spead open the wings on the terminals after you crushed them down to remove the pin from the old connector. And then you slip the pins into the new connector, pull the rubber boot over the end, and you're done.
The knock sensor was more complicated. In lots of ways. I couldn't find a replacement green 3-pin connector for the knock sensor anywhere. I knew that lots of European cars from 1980's to 2000's (I can confirm: VW, BMW, Benz, Jaguar, Saab) use these amp connectors, but the green 3-pos is a little more unique. After spending almost two hours at a pick-a-part salvage yard, I found my coveted green connector on a 2000 VW Passat. Right on the firewall and easy to snip off.
But, it isn't quite identical either. Amp part number 929552 and VW number 443906233. It appears to be a newer iteration of the connector. Quite nice actually. The pins slip into a pink/purple (my color-challenged eyes have no idea, anyone want to tell me what color it is?) holder. And the holder snaps into the green housing. Much easier to get the pins out this way.
The knock sensor uses a two-wire shielded cable. My dealer update connector had the shielding completely severed from the pin. Who knows what kind of glitches that was sending to the ecu. To repair it, I cut out some shielding from an older sensor cable. Then overlapped and interleaved the new shielding and the old shielding. Then put some wire heat shrink around it to keep it all firmly together. It actually worked pretty nicely. Here are a few photos that I snapped during the process.
The 964 cht, knock, and reference sensors appear likely to be discontinued entirely and replaced with the 993/996 sensors. Instead of hacking up your wiring harness to appease Porsche, a simple adapter cable is a much nicer solution.
What you need:
1. Your old sensor.
2. The updated female connector, pins, and boot.
It's as easy as clipping a long pigtail off of your old sensor, then attaching the updated connector onto the other end. You end up with an original male 964 connector to plug into your wiring harness and an updated female connector to plug into the 993/996 sensor. Why doesn't Porsche just sell these cables?
Weird, the edit button isn't showing up for me. Anyway, this is the long-overdue photo that accompanies my last post in this thread. This is the adapter between the new/old connectors that really should be sold by Porsche. Maybe the aftermarket is listening? I made this one up with readily available parts.
The part number in the photo is for the lower (new version) connector.
No reason to do all this. If you call your OPC, it's maybe $300 in parts and adaptors and then you assemble. The original sensor with the original plug is still available for about $85:
Bosch 0280130059
I think I bought from Pelican, but Amazon has it too
This info has been quite useful while I struggle with crumbling sensor connectors on my 964. While old style plugs are still available on the CHT and knock sensors, the crank/flywheel reference sensor is only available in the new plug style. So I am forced to either hack into my harness to switch plugs or make an adapter as you suggested. I agree that Porsche should have provided an adapter or at least provided a longer cable on the new sensors. BTW if anyone has found a source for old style male plugs that would fit the old style female receptacles, I would love to hear from you. Please post here or PM me.
FYI the old style female receptacle bears AMP part number 827578. The matching male plug has no part number.
the crank/flywheel reference sensor is only available in the new plug style.
Darn. Spoke too soon. Apparently the crank/flywheel reference sensor with the old style plug is available from Bosch. At least Amazon appears to offer them for about $50.
The Amazon vendor B2C Auto Parts no longer stocks crank sensors with the old style plug. I just called FCPEuro and they claim they can still get the crank sensor with the old style plug.
07-22-2014, 06:53 PM
CHT, knock, and reference sensors and connectors
