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metahacker
Samba Member
Joined: May 26, 2010
Posts: 692
Location: san.diego
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 Posted: Tue Oct 20, 2020 3:30 pm Post subject: Re: Temp Sensor II article (2020 update) |
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[quote="ratwell"]
| raygreenwood wrote: |
I dug out the 914 Tech Specs (Porsche equivalent of Without Guesswork).
Look at the last row in the TSII column. When is says "Resistor omitted", is this the same 270ohm ballast resistor your mention above above? Also which vehicles was this factory installed in, if any? |
the 73 is a bastard 914 year where the engineers tweaked the existing system to run right with the 2.0 before it was updated in 74. they used the 1.7L ECU to run it. it should have had a new Jetronic daughterboard with its own unique programming, which is where the density mapping for the engine is handled... e.g. the fuel map that cross references the AFM readings vs RPM and fires the injectors. Instead they hacked it. they put bigger injectors and futzed with the resistance of the temp sensor and modified the MPS for full load enrichment. |
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raygreenwood
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Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Tue Oct 20, 2020 5:34 pm Post subject: Re: Temp Sensor II article (2020 update) |
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[quote="metahacker"]
| ratwell wrote: |
| raygreenwood wrote: |
I dug out the 914 Tech Specs (Porsche equivalent of Without Guesswork).
Look at the last row in the TSII column. When is says "Resistor omitted", is this the same 270ohm ballast resistor your mention above above? Also which vehicles was this factory installed in, if any? |
the 73 is a bastard 914 year where the engineers tweaked the existing system to run right with the 2.0 before it was updated in 74. they used the 1.7L ECU to run it. it should have had a new Jetronic daughterboard with its own unique programming, which is where the density mapping for the engine is handled... e.g. the fuel map that cross references the AFM readings vs RPM and fires the injectors. Instead they hacked it. they put bigger injectors and futzed with the resistance of the temp sensor and modified the MPS for full load enrichment. |
Yes.....all of that....and add to this..... the fact that most 914 guys do not realize that the sought after...super expensive "039 906 051"...Porsche part numbered MPS....is nothing but the 022 906 051 E-series from the VW 412 and the 1.7L 914 from 1971 (and other years in type 4) .....but...the spacer ring against the copper diaphragm on the inside....is simply flipped to the other side...to give very slightly more "throw" or off the line and at shift points....full load impulse for the 2.0L. Besides that and a slightly different adjustment of the main load adjustment screw (which is tuning any owner needs to do anyway)......its the exact same MPS.
These kind of bastardized tweaks were not just done on the 914....we find them all through the type 4 engined D-jet series of VW and Porsche. I am not sure if they had any of the same issues on Mercedes, BMW, Renault or Volvo as well.
The one thing the factories never had while any of the D-jet was in production...is an actual book of "TUNING".....what to tweak, adjust or swap for running correction for fuels, climate, wear or altitude.....to correct engine behavior and performance. It seemed they were learning it as they went at the dealers....and only a little bit was getting "recorded" as tech bulletins.
I actually have a factory training cert....for D-jet, L-jet, CIS, CIS-E and digifant...I picked up at several classes in Atlanta back in the early 90's.
Virtually none of the D-jet information they taught....was useful outside of factory fresh and unmodified engines. I have already been driving and working on D-jet cars for about 15 years ...my daily drivers were D-jet from day 1.....and I already new tweaks and corrections that the factory had no literature for.
That being said...a lot of the Porsche guys that were working on track cars back then....call it resto-custom....already knew much of this as well.
Its great to say....in "GENERAL"....use this set of injectors with that ECU with this color code MpS...and it gets you close....but if you engine has 50k miles and you live at 2500 feet and deal with 100* weather.....that wont cut it. Ray |
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airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12716
Location: on a bike ride somewhere
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| Posted: Wed Oct 28, 2020 7:51 pm Post subject: Re: Temp Sensor II article (2020 update) |
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| airschooled wrote: |
| …Üro brand; the EMPI of the Porsche world. I’ve installed three and they’re still on the road. |
Make that two. One failed tonight at 55 miles. 
Robbie
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KentABQ 
Samba Member
Joined: September 11, 2016
Posts: 2406
Location: Albuquerque NM
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| Posted: Thu Oct 29, 2020 7:07 am Post subject: Re: Temp Sensor II article (2020 update) |
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You're doing better than I am, Robbie.
I have a container with about 6 or 8 crapped out TS2's.
And that drove me to installing this...
https://www.thesamba.com/vw/forum/viewtopic.php?t=...ght=sensor
...which works great in my rig.
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-Kent-
1976 Riviera, 1.8l FI chrome yellow VAN - "Chloe"
"I must say, how can you be in a bad mood driving this vehicle full of vibrant color.
Cars of today are so bland in comparison. It's like driving a celebration!" ---WildIdea
Bus ownership via emoticons:
         ---williamM |
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ratwell
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Joined: April 26, 2003
Posts: 8717
Location: Victoria, BC
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| Posted: Thu Oct 29, 2020 4:56 pm Post subject: Re: Temp Sensor II article (2020 update) |
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Link
Some of these real time air-fuel ratios (AFR) are below the typical "maximum power" portion of the AFR curve so I'm not sure if this is intentional or simply showing the range of values that can be acheived.
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SGKent
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Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Wed Nov 11, 2020 4:57 pm Post subject: Re: Temp Sensor II article (2020 update) |
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Reading about the failures on the new TSII re-pops, I went thru my parts stash to find a spare genuine new Bosch TSII that is now listed. https://www.thesamba.com/vw/classifieds/detail.php?id=2428390
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airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12716
Location: on a bike ride somewhere
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| Posted: Wed Nov 11, 2020 9:42 pm Post subject: Re: Temp Sensor II article (2020 update) |
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| ratwell wrote: |
| Would anyone like to mail me a broken one I can examine? |
Would you (or anyone else?) like a defective Üro brand sensor? I'm going to chuck it otherwise, unless someone wants to cut it open.
Robbie
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ratwell
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Joined: April 26, 2003
Posts: 8717
Location: Victoria, BC
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| Posted: Wed Nov 11, 2020 11:36 pm Post subject: Re: Temp Sensor II article (2020 update) |
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| airschooled wrote: |
| ratwell wrote: |
| Would anyone like to mail me a broken one I can examine? |
Would you (or anyone else?) like a defective Üro brand sensor? I'm going to chuck it otherwise, unless someone wants to cut it open.
Robbie |
Please pm me.
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'76 Doublecab
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airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12716
Location: on a bike ride somewhere
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| Posted: Sat Nov 21, 2020 11:23 pm Post subject: Re: Temp Sensor II article (2020 update) |
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A question…
I was tuning a 2.0L L-Jet Vanagon this week, and found it odd that the cold resistance was only 1300 ohms on TS2. This goes along with the 041A part that Ray mentioned…
022 906 041A (0 280 130 017) = 1300 ohms @ 68* F
I initially suspected it was a California emissions item, allowing less fuel to screw with the cat as the engine heated up. Does warm-up enrichment even bother a healthy cat?
Robbie
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ratwell
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Posts: 8717
Location: Victoria, BC
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| Posted: Sun Nov 22, 2020 2:22 pm Post subject: Re: Temp Sensor II article (2020 update) |
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I would think that the closed loop lambda system (narrow band oxygen sensor) would be designed around keeping the mixture lean and ensuring that the CAT is operating in the optimal range.
It could also be that the range of valves starting at 1300 ohms is necessary for compatibility with the closed loop logic during the warm-up cycle.
Which Vanagon model is this?
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airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12716
Location: on a bike ride somewhere
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| Posted: Sun Nov 22, 2020 2:45 pm Post subject: Re: Temp Sensor II article (2020 update) |
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‘82 California emissions. Totally stock, going in for smog this week.
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ratwell
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Posts: 8717
Location: Victoria, BC
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| Posted: Sun Nov 22, 2020 10:17 pm Post subject: Re: Temp Sensor II article (2020 update) |
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I checked my 80-85 Vanagon Fiche from Jan 1992 and there is only one TS2 listed: 022 906 041A
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airkooledchris
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Joined: January 25, 2005
Posts: 2707
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| Posted: Mon Nov 23, 2020 5:53 am Post subject: Re: Temp Sensor II article (2020 update) |
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| ratwell wrote: |
Link
Some of these real time air-fuel ratios (AFR) are below the typical "maximum power" portion of the AFR curve so I'm not sure if this is intentional or simply showing the range of values that can be acheived. |
Use this to see the range of values that you can sweep between (depending on your AFM's starting point), not as an example of what you would want to set yours at. This particular engine has always ran best with AFR's that are way too rich. I didn't build it so I can't say how it was setup, I just give it what it asks for.
The advantage in running that setup, to me, was that when I needed to climb a long grade I could floor it and enrichen the mixture to keep the heads a little cooler until cresting at the top, then toggle back over to the TS2 input and continue on.
I live now where there's more flat terrain, and higher speed limits. I see the advantage now in being able to dial in a little more fuel when trying to run at 75mph for an extended period of time, so my CHT's are running in the 400's. |
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Humpst
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Joined: March 05, 2021
Posts: 11
Location: Bowling Green, Kentucky
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| Posted: Tue Aug 31, 2021 7:25 am Post subject: Re: Temp Sensor II article (2020 update) |
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Since I acquired a 1972 VW Bus about 5 months ago, I have used this site OFTEN for troubleshooting issues. After searching, reading and talking with others I decided to post in this thread to see if I could get some help.
My bus has a 1.7 L motor that has a single weber carb setup. The engine idles well, but is very loud on acceleration. In the attached picture there is a hole in the head just to the rear of the bus of the intake manifold on cylinder #4. I am getting air leaking out of this hole and I have been told it might be where a head temp sensor is supposed to be mounted? Hoping for some help in confirming this is actually the case? Should I put a temp sensor back in? If not, can this hole be plugged? If so, what is thread size for a bolt to use to plug the hole?
Thanks for the help,
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Wildthings
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Joined: March 13, 2005
Posts: 50331
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| Posted: Tue Aug 31, 2021 7:59 am Post subject: Re: Temp Sensor II article (2020 update) |
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| Humpst wrote: |
Since I acquired a 1972 VW Bus about 5 months ago, I have used this site OFTEN for troubleshooting issues. After searching, reading and talking with others I decided to post in this thread to see if I could get some help.
My bus has a 1.7 L motor that has a single weber carb setup. The engine idles well, but is very loud on acceleration. In the attached picture there is a hole in the head just to the rear of the bus of the intake manifold on cylinder #4. I am getting air leaking out of this hole and I have been told it might be where a head temp sensor is supposed to be mounted? Hoping for some help in confirming this is actually the case? Should I put a temp sensor back in? If not, can this hole be plugged? If so, what is thread size for a bolt to use to plug the hole?
Thanks for the help, |
That was for the air injection on 73 & 74 models. You can plug it with a 10 x 1mm bolt or a 10mm valve adjuster screw. An 1/8" steel flush style pipe plug will also work. |
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