Thermo time switch + cold start valve question

[mxl556]

Is there a way to jump the thermotime switch so the cold start valve always sprays fuel during cranking? I am thinking to disconnect the thermotime switch connector and hook up a jumper wire to it. Is it going to work? I just want it done temporarily so I will not kill my starter while I am troubleshooting the following problem:

It very hard to start my 81 320i when it is hot outside (the engine is cold). If the ambient temperature is over 75-80F it takes a lot of cranking to get it started.
When the ambient temp is below 75F the engine starts right away. It also starts great when the engine is at operating temperature.

I suspect that the thermo time switch/cold start valve is not operating when they should. I tested it by putting some ice on the thermotime switch today and it started right away, in 85F!

What I want to do for now is to make sure cold start valve sprays fuel during cranking regardless of the temperature. How do I make it happen?

Thank you,
Max

[epmedia]

I've never tried this, but it may do what you want...

(disconnect both wires from the tts)
The brown/black wire on the tts, is the the wire that puts the 'timed' ground to the cold start valve. Connect this wire to the engine ground with your jumper wire (bypassing the tts). Don't flood the engine with fuel!

Here's a link to the pdf electric manual.

1981-1983
http://www.findmymerchant.com/images..._1981-1983.pdf

* just fyi: I once played with the cold start valve wiring and somehow wired it so that the starter solenoid accidentally stayed engaged. that was weird. I don't think what you're trying to do will cause same strange result as I caused.

[mxl556]

Thank you! That is exactly what I needed. I need to rig it temporarily for testing purposes and to be able to start the engine when it is hot out and not burn up the starter...

Max

[alexgauld]

Hey I've been having the same problem for the last month or more so I flipped out my TTS with my parts car today and it seems to have solved the problem. Thanks for your help and this forum is great!

[mxl556]

I grounded the wire on the valve cover and it starts great. Little rich when warmed up but it does not flood or stall, so it is OK for now.
Anyone has a good used TTS for sale?

Thanks,
Max

[mxl556]

Just an update, I replaced TTS with the new BMW part and it solved all the problems starting when it is warm/hot outside. Old TTS worked OK below 50-70F but did not work when it was ~70F-95F, therefore starting cold engine in that temperature range was very hard. I also replaced the temp gauge switch which I highly recommend as $20 switch solved inconsistent gauge readings.

Max

[dreiermann]

The $20 is for the temp gauge switch and not the thermo-time switch, right? The TTS looks to be about 10x that amount.

[mxl556]

I replaced both. Temp gauge switch was cheap enough to do at the same time. Both switches cost me around $200. At least these are available...

Max