Page 1 of 2 1 2 LastLast
Results 1 to 10 of 14

Thread: What's the procedure for testing the electrical connections to the thermotime?

  1. #1
    Senior Member
    Join Date:  Jan 2015

    Posts:    241

    What's the procedure for testing the electrical connections to the thermotime?

    My car is difficult to start when it has not been started in several days. The cold start does not fire unless I connect the wire to the (other thing I can't think of at the moment) - then it works fine. I have also done the multi meter testing on the Thermo time switch itself and that checked out. I have a new thermal time switch in hand but before I go changing it I am wondering if there is a bad electrical connection to the existing one on the car. What is the procedure for checking that out? Thank you
    81' gas flap. Sept build. 14k miles. Mostly original. Updating things...

  2. #2
    Senior Member Bitsyncmaster's Avatar
    Join Date:  May 2011

    Location:  Leonardtown, MD

    Posts:    6,923

    My VIN:    03572

    My car when I got it had a bad connection on a bulkhead pin that caused the CSV not to work. You would have to start with the schematic, first checking if the 12 volts is at the CSV when the starter is cranking and checking there is ground on the other pin. You can check the ground side first with a cold engine.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  3. #3
    Delorean Guru
    Join Date:  May 2011

    Location:  Northern NJ

    Posts:    6,498

    My VIN:    10757

    Club(s):   (DMA)

    Quote Originally Posted by Bitsyncmaster View Post
    My car when I got it had a bad connection on a bulkhead pin that caused the CSV not to work. You would have to start with the schematic, first checking if the 12 volts is at the CSV when the starter is cranking and checking there is ground on the other pin. You can check the ground side first with a cold engine.
    Reference the schematic on D:04:06 and the description of the circuit on D:01:09-10. Difficult to properly test the TT switch except in the circuit. Make sure the plug to the TT switch is connected correctly. It is keyed but can be forced into it improperly and the polarity to that switch is VERY important. So important that if hooked up incorrectly you will burn the TT switch up. If the CSV fires when you do the plug swap, that means either the TT switch is bad, not properly grounded, a wiring problem or no 12 volts during cranking from the starter. Make sure there is nothing plugged into the hot start relay plug by the fuse block. You cannot use any teflon tape or sealant on the TT switch when threading it into the water pump. It MUST be electrically grounded to work.
    David Teitelbaum

  4. #4
    Senior Member
    Join Date:  Jan 2015

    Posts:    241

    Quote Originally Posted by David T View Post
    Reference the schematic on D:04:06 and the description of the circuit on D:01:09-10. Difficult to properly test the TT switch except in the circuit. Make sure the plug to the TT switch is connected correctly. It is keyed but can be forced into it improperly and the polarity to that switch is VERY important. So important that if hooked up incorrectly you will burn the TT switch up. If the CSV fires when you do the plug swap, that means either the TT switch is bad, not properly grounded, a wiring problem or no 12 volts during cranking from the starter. Make sure there is nothing plugged into the hot start relay plug by the fuse block. You cannot use any teflon tape or sealant on the TT switch when threading it into the water pump. It MUST be electrically grounded to work.
    Thanks guys. I will try that out. I do have Bitsyncmaster's hot start relay in there. What is the reason for unplugging it? Does it prevent thermal time switch from working? I have only had the hot start relay in there for the past couple weeks. The car has behave the same before this too if that helps. Dave mentioned that he never has his Thermo time switch plugged in. Would it just be simple to unplug it to make the CSV always fire? Thanks
    81' gas flap. Sept build. 14k miles. Mostly original. Updating things...

  5. #5
    Senior Member
    Join Date:  Jan 2015

    Posts:    241

    I think I found the reason the Thermo time was not triggering the coldstart. The ground was fine but there was a wire touching the exhaust the burnt out the outer rubber. This was one of the wires coming off of the starter but I believe his feeding power when the starter is cranking. I think it was shorting out. After moving away the wire and the car started right up after not being started for at least a week. I bent the wires so they would kind of stay away from the pipe but it's not really a sure thing. Does anyone have a trick for getting these wires away from the wire or putting some kind of protective sleeve over them?

    IMG_1740.jpg
    Attached Images
    81' gas flap. Sept build. 14k miles. Mostly original. Updating things...

  6. #6
    Junior Member jerrysony's Avatar
    Join Date:  Apr 2015

    Location:  Mexico

    Posts:    25

    My VIN:    2607

    Hello everyone. I'm having a weird situation with the
    Thermo time:
    The car runs always at low temp. The needle doesn't even reach the first mark. I've noticed that the cooler fans start too soon and they keep running 10 or 15 minutes after the car has been shut down. (Draining my battery) . The car is carb converted and cold weather is not an issue. I 've unplugged the wires to the otterstart and still the fans behave the way described above.
    Why is the TT messing with the cooling fans? Since the car is carb in warm weather should I get rid of it?

    Enviado desde mi SM-G950F mediante Tapatalk

  7. #7
    Senior Member Bitsyncmaster's Avatar
    Join Date:  May 2011

    Location:  Leonardtown, MD

    Posts:    6,923

    My VIN:    03572

    The thermal time switch has nothing to do with the cooling fans. If your engine has a carb, you would not need the TTS since it only affects the cold start valve which you also do not need with a carb.

    Post a photo of your relay compartment and we may see why your fans are running.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  8. #8
    Junior Member jerrysony's Avatar
    Join Date:  Apr 2015

    Location:  Mexico

    Posts:    25

    My VIN:    2607

    Quote Originally Posted by Bitsyncmaster View Post
    The thermal time switch has nothing to do with the cooling fans. If your engine has a carb, you would not need the TTS since it only affects the cold start valve which you also do not need with a carb.

    Post a photo of your relay compartment and we may see why your fans are running.
    here are some photos from the relay compartment and also from the thermotime socket and wiring close to the resistor. Im guessing that maybe during the carb swap ther mixed some of the wiring? Also, Ive noticed that on other carb cars the resistor is not so crowed with therminals. Should I disconect some of them?
    Attached Images

  9. #9
    Senior Member Bitsyncmaster's Avatar
    Join Date:  May 2011

    Location:  Leonardtown, MD

    Posts:    6,923

    My VIN:    03572

    Looks like someone has done some wiring changes. I see a standard relay in the fan relay socket but no fan fail socket. I also think the cooling fan circuit breaker has been moved. Your fans may be working OK but my guess is your gauge is not reading correctly. I would guess the PO replaced the gauge sensor with a wrong part and that makes your gauge always show low readings.

    The otterstat was normally in the coolant pipe on the drivers side near the engine. That is the device that turns the fans on when the coolant temp gets hot.

    The TTS is located on the water pump. That device just turned the CSV on when the engine is started cold.
    Dave M vin 03572
    http://dm-eng.weebly.com/

  10. #10
    Junior Member jerrysony's Avatar
    Join Date:  Apr 2015

    Location:  Mexico

    Posts:    25

    My VIN:    2607

    So, I guess the next steps would be:
    1- Locate the cooling fan circuit breaker and place it on the right place on the relay box. If not found, try to figure out the work done by the PO.
    2- (optional) wire jump the fan fail relay.
    3- Unplug the TT (for good since the car is carb and not needed anymore) and jump the wires to the otterstat to check if the fans starts.
    a) if they do, check the gauge sensor and verify that the fans turn on at the proper temperature.
    b) If they dont, maybe do a rewire job until the otterstat circuit the fans.
    Is that correct?
    Thanks in advance.

Page 1 of 2 1 2 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •