Just purchased a 1973 2.0 but it idles bad. I rung out the resistance in the system and found a faulty temp 2 read 52ohms and was a 003.
Can't find the proper 017
Any help would be great!

Thanks guys
Chris

Read through this site?

http://members.rennlist.com/pbanders/djetparts.htm

Function: Senses engine temperature and sends signal to the ECU to provide mixture compensation. Proper part for your application and proper functioning is extremely important!
Normal Value(s):
0 280 130 003 and 0 280 130 012: about 2.5 K ohms at 68 deg. F, less than 100 ohms with hot engine.
0 280 130 017: about 1.3 K ohms at 68 deg. F, less than 100 ohms with hot engine.
See Notes section below for more data on the resistance vs. temperature values of these sensors.
Failure Modes
Open: The ECU interprets an open sensor as a signal to greatly richen (e.g. I've measured an over 3X effect) the mixture. This usually makes the car impossible to start and causes it to stall if the sensor fails open while running. Check by disconnecting the sensor from the wiring harness and measuring the resistance to ground, refer to the values above.
Shorted: The ECU interprets a shorted sensor as a signal to lean out the mixture (about 30% leaner). The car may run and start in this condition, but will have poor idle and drivability. Check by disconnecting the sensor from the wiring harness and checking the resistance to ground. Note that shorts are often intermittent, caused by nicks in the sensor wire and by exposed contacts to the wiring harness touching ground. Check by inspection.
Stuck Value: I've heard of at least one case of the sensor being stuck at a value (e.g. 50 ohms) and not varying with temperature. Depending on the value it gets stuck at, it can result in either poor cold or hot performance, or both. Check by measuring with an ohmmeter as described above.
Mismatched: The 1973 2.0L's came with the 0 280 130 017 head temperature sensor, 039 971 762 A ballast resistor, 0 280 100 037 manifold pressure sensor, and the 022 906 021 E version of the ECU. This set of components must be used together. Any substitution will result in idle and part-load performance problems, and possible poor fuel economy. Additionally, use of any of these 1973 2.0L components with a 1974 2.0L setup will also cause problems. See the table above for the suggested setup for both 1973 or 1974 2.0L engines. If you have a 1973 2.0L and you want to keep the original setup, make absolutely certain that you have the correct combination of components. The 0 280 130 017 head temperature sensor's cold (70 deg F.) resistance is about 1200 ohms, compared to 2300 ohms for the 0 280 130 003 and 0 280 130 012 sensors. Use of the ...017 sensor with the 039 906 021 ECU (1974 model) will result in a lean mixture during warm up, causing low idle and/or backfiring on over-run. Use of the ...012 or ...003 sensor with the 022 906 021 E ECU (1973 model), with or without the ballast resistor, will result in a rich warm-up mixture. Take the extra time and determine exactly which head temperature sensor is installed in your car and make sure it matches the setup.
Notes: This resistance of this sensor is one of the primary factors in adjusting the mixture and it has a strong effect. An additional issue is the availability of the 0 280 130 012 sensor. I have found this sensor difficult to locate, and most shops substitute the 0 280 130 003 sensor for it. As far as I can tell, it is either exactly the same or nearly identical. Bosch even lists the ...003 sensor as being cross-referenced to the Porsche/VW part number 311 906 041 A. See the entry above for the intake air temperature sensor for theory on how these sensors work.
Fixes for Crappy Warm-Up: For whatever reason, VW/Porsche made the CHT sensor such that the warm-up mixture is usually too lean, resulting in poor idle and drivability. Two ways to fix this. First, you can add up to 150 ohms of ballast resistance to the sensor to bias the curve up towards a richer condition. Don't go over this amount of ballast because it will begin to affect the warmed-up mixture. Second, you can construct a spacer as described on Richard Atwell's page, that delays heat transfer from the head to the sensor, making the mixture richer during warm-up. I made mine using materials from my local ACE Hardware: a M10x1.0 tap and wrench, 11/32" drill bit, M10x1.0 bolt, and a M8x1.25 coupling nut w/13 MM hex. Drill out the coupling nut and tap it to M10x1.0. Cut it down to 16 MM length. Cut a 16 MM stud from the bolt, thread it into the coupling nut so that when you attach the sensor on the other end, it just jams the stud in place. Align the flats and install. BTW, you can also do both fixes in combination (like on my car!).
Installation Notes: Installing this sensor can be tricky. The best solution I've found is to buy a deep 13 mm socket and a 3" extension (I bought mine at Checker, about $5 for both). Use a Dremel tool with a cut-off wheel to cut off one of the corners of the four-sided end of the extension (the part that goes into the socket) to create a gap that the sensor wire can be threaded through. ALWAYS USE SAFETY GLASSES when doing this kind of work with a Dremel tool. Filing works, too, but it will take a very long time. Make sure to use the copper washer that comes with the sensor - the washer assures good thermal conductivity to the head and prevents loosening. Keeping the washer from falling off during installation can be difficult. First, to keep the sensor from being pushed back into the socket during installation (which will pop the washer off, and it'll fall into the head air fins), position the sensor so that it's sticking out a bit, then tape the wire with a single loop of masking tape to the extension. The wire will resist the sensor being pushed back into the socket. To keep the washer on the sensor, I use a couple of tiny drops of superglue to hold it in place. The glue bond will be broken when the sensor is tightened. DO NOT overtighten this sensor, just get it snug. It's easy to strip out the head threads and then you'll have to pull the engine to fix the problem.
More Data!!: Below is some characterization data I took on each sensor at three different temperatures (one data point missing). Note that these are representative readings - there is significant manufacturing variation in these sensors. All data measured with a freshly-calibrated Wavetek LCR55 meter.

Sensor Temp = 39 deg. F
(ice bath with thermometer) Temp = 61 deg. F
(room temperature)
Temp = 210 deg F
(boiling water at 1000 feet altitude)
0 280 130 003 6.10 K ohms 2.94 K ohms 199.3 ohms
0 280 130 012 NA 2.85 K ohms 191.2 ohms
0 280 130 017 3.63 K ohms 1.74 K ohms 124.7 ohms

The Bosch 017 is also VW 022 906 041A. The 017 is designed to work with a 260 ohm resistor. It was used only on the 2.0 for 1973. Does your car have the resistor? I THINK by the time you add the values of the resistor and the values of the 017 you will be very close to the value of the 012.

All the old Bosch information show both parts numbers replaced by the 012. Additional information can be found at Richard Atwells Bus pages BUT it only adds to the confusion.

German Supply in Canada shows to have a VW 022 906 041 in stock then shows the Bosch 012.

Brad Mayuer has threaded head spacers that you can try tricking the sensor.

My 1974 2.0L had poor cold idle condition and the spacer helped tremendously. If you don't have the resistor mentioned, you will have to head to your local electronics store (Radio Shack still around?) and purchase a resister you can use there.


Also, could simply be that you need a newer, well functioning 012 CHT. They do go bad so replacing your 003 with an 012 may help.

thanks guys for the info. I did read the rennlist info and Im a bit confused with why I m able to use a 012 on my 73 system when the value for a 012 is 2.3k ohms and the 017 is 1.3k ohms and that they state I must use only 017. If theres guys out there with a 73 setup and use 012 and it works then I'll give it a try. I do know that the 003 sensor is faulty because it reads 80 ohms at 70f.
You guys are great here and very helpful

No resistor was installed but the last owner installed a pot that he adjusted as it warmed up. Im now in the process to sort it all out.