TTS question on my 82 aircooled

[t'sunamibus]

My thermo time switch failed the afc and Bently's test. Before replacing it I would like to rule out any wiring issues. From what Ive read it would seem that the tts's dont fail often. Although its not in any test procedures shouldnt I be able to read continuity at the tts when cold? ( no continuity cold on this one )

[tencentlife]

Each pin presents a circuit to ground thru the body of the TTS. One is the switched circuit, it should be closed when cold, and open as the switch is warmed past the temp stamped on the body, generally 80C as I recall. The other circuit is the heater coil so it should show a set resistance to ground, I think it's around 30ohm (that would make it 5w which sounds about right) but the book might say. Knowing the ohms value doesn't matter, resistance in a heater coil doesn't shift or anything, if the coil is intact it will show resistance, if it's not it will be open.

On the connector, one pin (the one that connects to the TTS switched circuit) should show continuity with one pin in the cold-start valve's connector. The other pin should go hot when the starter cranks (powering the TTS heater coil), as should the other pin at the CSV.

These do fail all the time, actually, in my experience I would say no L-jet or K-jet component fails as much as the TTS.
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[t'sunamibus]

[Wildthings]

I think the maximum temperature for the TTS is 80°F and not 80°C. Been wrong before though.

[tencentlife]

Yeah I think you're right, it's probably 30ºC which is 86ºF. That's a reasonable temp not to need the CSV.
_________________
Shop for unique and useful Vanagon accessories at the Vanistan shop:
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Please don't PM here, I will not reply.

If all you do with your axe is grind it, you'll just end up with a piece of hickory. Better throw it on the fire, cuz no wood's gettin' chopped!

Experience is death to doctrine.

[Randy in Maine]

From type4.org....

"Resistance between terminal “W” on thermo-time switch and ground

The required resistance values differ between thermo-time switch models.

The resistance should reach 0 Ohms (continuity) with engine temperature below:

Bosch part no. Temperature (F) Temperature (C)
0 280 130 219 50 10
0 280 130 221 56 13
0 280 130 214 86 30

The resistance should rise to infinity with engine temperature above: Infinite resistance with engine temperature above:

Bosch part no. Temperature (F) Temperature (C)
0 280 130 219 68 20
0 280 130 221 74 23
0 280 130 214 104 40

If resistance value lies outside of specification, thermo-time switch is defective."

[t'sunamibus]

[t'sunamibus]

Heres the info for my '82 Westy's tts
vw# 043906163a
bosch# 0280130214

I initially had cranking issues so Ive installed a new starter, new battery cables and also a hard/hot start relay kit purchased here from thatvwbusguy. Today im cleaning up my ground strap from chassis to transmission and installing an 8ga ground kit from the battery to chassis, trans, fi ground engine bolt and the firewall. I might be taking unnecessary steps but im try to be a thorough as I can, ive got a rebuilt bottom end with a new top end and heads, all new fuel system and lines in a bus that ive never driven thats been sitting next to the ocean for 3 years.
We'll see...

[t'sunamibus]

It Runs!!
While installing my ground kit I discovered one of the fi ground terminals wasnt in the best of shape and was loose so I ganged them together and ran them to the firewall ground I installed today. It was still giving me grief cranking so I hooked an additional battery direct to the starter and ground strap and jumpered the starter from underneith the bus while watching my vom, that took care of my voltage drop while cranking and the damn thing fired after a bit..woo hoo! Im thinking todays cranking issues were created between a possibly tight lower end and valvoline 30wt race oil. After running it in it cranks fine now and fires right up.

[p3p1k]

Could someone explain to me the graph with temperature and TTS time?
Do I understand correctly that at 0°C the CSV will be open for 4-8sec?

I tried the TTS test on the table yesterday. I took a 12V power supply, - I connected the cable to the TTS holder, + I connected to the bulb and to the G contact, W contact I connected to the bulb.
Room temperature +- 25°C - the bulb was on for 0.5sec
Frozen vegetables placed on the TTS after 30 min +-5 °C the bulb lights up for 8 sec.
I heated the TTS with a hair dryer +- 35°C - the bulb does not light up

when I have the car in the sun it is impossible to start and I believe the car will heat up to more than 35°C under the tarpaulin and therefore the TTS and CVS will not be open.
I'm afraid buying a new TTS will not solve this problem and I will have to do a dashboard switch. I come from the Czech Republic (Europe) and here the valve costs 250-300 US (a lot of money for me to test )
I'm still going to try and replace the TS2

[MarkWard]

System fuel pressure is probably not sustaining or the injectors are leaking down. Further diagnosis would be required.

If the van runs fine, another solution would be to wire a push button directly to the cold start valve. VW came up with Pulse Relay Kit to fix a hot start problem for the CIS cars. Unfortunately the relay is NLA. It bascially fired the cold start valve with a pulse everytime the engine was cranked regardless of the temp. Worked really well. Your push button could prime the engine while cranking to get it to light.

Otherwise you need to figure out why it needs the extra fuel to start warm. Fun stuff.