What could cause a TS II to fail prematurely?

[Xevin]

[KTPhil]

No switches (more chances to fail!). Upon suspected failure, my plan is to substitute the fixed resistor for TS2 by plugging into the harness after disconnecting the pigtail to TS2. Easy access, on top of the motor and tin. 200 ohms is close enough to drive long stances, not just limp.

Apologies for putting Type 3 specific info in this thread. But I guess anyone searching for TS2 may find this thread.

On Buses, is there a handy T1 connector that the TS2 pigtail connects to on top of the motor (like the Type 3 has)? Likely easier than getting out a special socket and fiddling getting it properly and safely torqued while on the side of the road.

Sorry for the detour... here is a pic of the T3 engine bay. You can see the plastic T1 connector just in front of the coil... easy-peasy to swap. (ignore the red circle, I stole this pic from a different thread)

I presume there is a similar T1 connector in about the same location on the T4 motors?

Of course, this post might be relevant for the madman that came up with this Type 3 solution... woo-hoo!!

_________________
Current Fleet:
- '71 Fastback
- '69 Westfalia
Retired:
- '67 Beetle
- '65 Beetle (x2)
- '65 Bus
- '71 Squareback

[raygreenwood]

Xevin said:

[KTPhil]

For the fixed alternative, I was thinking of something like this:
https://www.digikey.com/en/products/detail/koa-spe...J0QAvD_BwE

The ECU used 1/4 watt resistors for most parts, didn't they?

In that case, despite being installed externally, I would think that would suffice for this use. I think TS2 is part of the pulse width modification circuitry, and not part of the injector driver circuits, so it isn't carrying much current. It's been a while since I studied the schematics copied here:
https://www.sw-em.com/bosch_d-jetronic_injection.htm

My thought was to encapsulate it into a T1 type connector housing:
https://vwispwest.com/connector-p-spade-connector-1-1-p-111937077/

Maybe pot it for moisture protection. One lead goes to a round lug to screw to the generator ground lug, the other to the ECU harness.

Like with your suggestion, it could be left in the engine bay, and then upon suspected failure, I just swap the ECU wire from the TS2 T1 connector to this one. Might be handy when checking other FI adjustments, so it holds TS2 at a constant, reducing the variables as you tweak idle speed, MPS settings, etc.
_________________
Current Fleet:
- '71 Fastback
- '69 Westfalia
Retired:
- '67 Beetle
- '65 Beetle (x2)
- '65 Bus
- '71 Squareback

[Xevin]

[KTPhil]

Does someone have a photo of the Bay engine compartment showing the connector that the TS2 pigtail plugs into? I tried search but came up empty.
_________________
Current Fleet:
- '71 Fastback
- '69 Westfalia
Retired:
- '67 Beetle
- '65 Beetle (x2)
- '65 Bus
- '71 Squareback

[raygreenwood]

[Bnanwel]

The “Vespa gimmick” is not a gimmick. It’s just a replacement TS2 that happens to be used on a Vespa scooter. Replace the sensor, and it works. I have one installed as a quick backup outside the tin in a tapped hole next to #3 intake. I can’t tell any difference in drivability. It’s also cheaper and has a more robust connection point, a potted male spade connector on top.
_________________
‘72 Karmann Ghia Conv.
‘73 Karmann Ghia Coupe
‘74 Karmann Ghia Coupe
‘70 Deluxe
‘72 Deluxe

[Xevin]

[Bnanwel]

Good point, Xevin. For the record, that idea was not mine.
_________________
‘72 Karmann Ghia Conv.
‘73 Karmann Ghia Coupe
‘74 Karmann Ghia Coupe
‘70 Deluxe
‘72 Deluxe

[TrollFromDownBelow]

Just thought I'd provide an update.....

Check the TSII for cold resistance, and it measured ok (2.9k at abt 60 degrees). Wiggled the sensor wire around with the meter on it, and it seemed fine, did the same with the FI harness wire, and it seemed fine too; both had continuity. Made me think it was a ground issue.

Took out the TSII and put high temp copper anti seize (that's what Oreilly had in stock) put it back in and tightened it back up. It seemed to have fixed it...took it on a 20 minute highway run.

Does anyone know the torque spec for the TSII?
_________________
1976 Westy (aka Tripod)
2.0 liter FI solid lifters
212k miles

[raygreenwood]

[SGKent]

pair of two position switches or a three position selector switch.

If a pair of two position switches - one is stock TSII or second switch. 2nd switch selects average resistance when bus is hot, the other position is a slightly richer position for starting or enriched mixture climbing long grades.

If selector switch, position one is stock TSII, position 2 is average resistance, and position 3 is enriched mixture for starting cold or climbing long grades.

I bought a bunch of genuine Bosch TSII before they went NLA so I am covered but the switches will work for someone who is concerned about TSII failures. There are other threads where people have even put in dial a resistance to change the resistance at will. Adding a couple switches or selector in the cockpit area would be easy to do. Just run two high-quality low-resistance wires back to the original TSII position to keep its curve the same and put the switches or selector near the driver.
_________________
Canned Water - the new California approved parts cleaner (except in a drought in which case rub it with sand).

George Carlin:
"Most people don't know what they're doing, and a lot of them are really good at it."

Skills@EuroCarsPlus:
"never time to do it right but always time to do it twice"

[TrollFromDownBelow]

[airkooledchris]