# testing CIS-E thermo time switch and cold start valve... tips?



## Obin Robinson (Oct 20, 2000)

i am tracking down the problem with my GTI and i think it's either:
- a bad cold start valve
- a bad thermo time switch
i tested the thermo time switch circuit and it seems like it's getting NO voltage or current during start up. same goes for the cold start valve. i followed the procedure in the Bentley and it basically says that either the thermo switch is bad, or the electrical connections TO the switch are bad.
so i either have a bad wiring problem or a bad switch. i'd rather not replace the switch if i don't need to (only to find out it was a wiring problem. also, the coolant temperature sensor is apparently reading the wrong range. should I start with the sensor first? can a bad reading from the coolant temp sensor throw everything else off and cause no voltage to reach the cold start valve or thermo time switch?
thanks!
obin


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## Mr. Tickles (Jul 25, 1999)

*Re: testing CIS-E thermo time switch and cold start valve... tips? (Obin Robinson)*

check the resistance of each sensor and compare to the supplied bentley charts. That will at least tell you if the sensor is functioning or not. Ohm out your wiring and make sure they have continuity.


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## switch_900 (Aug 29, 2001)

*Re: testing CIS-E thermo time switch and cold start valve... tips? (Mr. Tickles)*

take your cold start valve out of the manifold and put it in a cup. Don eye protection and jump it from the battery. Does it spray gas in an even pattern...good CSV. Take a reading of your coolant temp sensor. You say it's off? Now take the main line off the ECU and make sure you get the same resistance in the wires (no bad connections). If the reading is off at the sensor bad CTS if it's more off at the ECU harness then bad wiring. Your CTS will totally affect your cold start valve. If you are reading the wrong resistance from your CTS your fifth injector will either continuously fire or never fire...depending on the resistance across the sensor. Have you done all the tests in the fuel chapter of your bentley's that involve taking the harness off the ECU? I find a lot of peoples problems by starting there and working backwards.


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## Obin Robinson (Oct 20, 2000)

*Re: testing CIS-E thermo time switch and cold start valve... tips? (switch_900)*

ok, we did all those bentley tests and determined that the Thermo Time Switch and Cold Start Valve are NOT getting ANY voltage as the car is starting. i checked the wire and there appears to be continuity on that circuit back to the starter, and the starter obviously works fine.
bad fuel pump relay?
thanks!
obin


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## switch_900 (Aug 29, 2001)

*Re: testing CIS-E thermo time switch and cold start valve... tips? (Obin Robinson)*

Is this car an automatic? Automatic Golfs have a neutral safety switch between the ignition switch and the CSV and Thermal time switch that would only affect power to these two things. Otherwise, if it's a manual, and if you have power to the starter motor from the ignition switch then you probably have a break in the wire from the ignition switch to the above items. If it's CIS I think there is a pulsing relay in line between the ignition switch and the CSV. If it's CIS-E it's a direct loop where the power goes to the thermotime switch and CSV from the ignition (black and red wire) with a green and white wire that goes between the csv and the switch. Good luck.


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## Obin Robinson (Oct 20, 2000)

*Re: testing CIS-E thermo time switch and cold start valve... tips? (switch_900)*


_Quote, originally posted by *switch_900* »_the CSV and Thermal time switch that would only affect power to these two things. Otherwise, if it's a manual, and if you have power to the starter motor from the ignition switch then you probably have a break in the wire from the ignition switch to the above items. If it's CIS I think there is a pulsing relay in line between the ignition switch and the CSV. If it's CIS-E it's a direct loop where the power goes to the thermotime switch and CSV from the ignition (black and red wire) with a green and white wire that goes between the csv and the switch. Good luck.

automatic?!? blasphemy!!!! 5 speeds ONLY for me







.
break in the ignition wire? hmm, lemme check that from the switch to the TTS/CSV circuit.
offhand, the starter works fine and i had continuity from that one wire on the starter to the black/red wire on the thermo time switch. still think it might be from the starter though?
also, i ordered a new fuel pump relay just in case that is what went bad.
thanks!
obin


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## switch_900 (Aug 29, 2001)

*Re: testing CIS-E thermo time switch and cold start valve... tips? (Obin Robinson)*

I wouldn't bother with the fuel pump relay. On an 86 the power goes from the ignition switch to the relay to the transfer and main fuel pumps and the fuel gauge. The power to the CSV is on a seperate circuit.


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## Obin Robinson (Oct 20, 2000)

*Re: testing CIS-E thermo time switch and cold start valve... tips? (switch_900)*


_Quote, originally posted by *switch_900* »_I wouldn't bother with the fuel pump relay. On an 86 the power goes from the ignition switch to the relay to the transfer and main fuel pumps and the fuel gauge. The power to the CSV is on a seperate circuit.

i ordered one just in case.
what circuit powers the TTS/CSV? worst case.. what one could i hack it into?
thanks!
obin


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## Obin Robinson (Oct 20, 2000)

*Re: testing CIS-E thermo time switch and cold start valve... tips? (Obin Robinson)*

ok, i ordered a new Thermo Time Switch. after letting the car cool overnight it was still reading 36 ohms. it should read continuity. no wonder the car is so hard to start.
thanks everyone!
obin


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## Obin Robinson (Oct 20, 2000)

*Re: testing CIS-E thermo time switch and cold start valve... tips? (Obin Robinson)*

just an update....
after a new thermo time switch, the cold start valve still didn't work. so i replaced the cold start valve and the car starts fine and idles ok








thanks everyone!
obin


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