 Thermo Time Switch, Purpose |
|
|
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
|
  |
| 2-OH! |
 May 7 2007, 04:39 PM
Post
#1
|
|
Senior Member  Group: Members Posts: 552 Joined: 17-October 03 From: Santa Clarita, Kalifornication Member No.: 1,253  |
I have already sent this to Brad Anders, but I decided I would like your opinion as well...
Going thru hell with 1973 - 1.7 D-Jet running awful from 0 to 180 degrees (oil temp)...Bucks, snorts, spits, unstable RPM, all before 180...Runs OK (not great but OK), after 180... Newly rebuilt MPS (Bleyseng), switched ECU's with known good unit, no help... Newly purchased from Pelican, Head Temp Sensor shows 3.16 OHMS...Old HTS shows 3.65 OHMS... Currently re-sealing all intake runners, plenum, TB, etc. looking for vacuum leaks...While I had the Thermo-Time sensor off the block, I checked it with an OHM meter both hot and garage temp (approx. 75 degrees) and got no reading at all...Indicating to me that the unit is open... As I read the wirnig diagram, all the Thermo-Time switch does is complete the ground for the Cold Start valve and therefore would not effect starts in 70 degree weather... Is that your intrepretation of the Thermo Switch...If so, I can eliminate that as a possible source of my trouble... Thanks, 2-OH! |
   |
 
|
| swl |
May 7 2007, 09:14 PM
Post
#2
|
|
Senior Member Group: Members Posts: 1,409 Joined: 7-August 05 From: Kingston,On,Canada Member No.: 4,550 Region Association: Canada |
QUOTE(2-OH! @ May 7 2007, 02:39 PM)  As I read the wirnig diagram, all the Thermo-Time switch does is complete the ground for the Cold Start valve and therefore would not effect starts in 70 degree weather... Is that your intrepretation of the Thermo Switch...If so, I can eliminate that as a possible source of my trouble... That's the way I read the wiring diagram too. Fits with other descriptions as well. |
|
|
|
| jim_hoyland |
May 7 2007, 09:17 PM
Post
#3
|
|
Get that VIN ? Group: Members Posts: 9,286 Joined: 1-May 03 From: Sunset Beach, CA Member No.: 643 Region Association: Southern California 
|
|
|
|
|
| MrKona |
May 7 2007, 10:20 PM
Post
#4
|
|
Senior Member Group: Members Posts: 597 Joined: 25-July 05 From: Santa Rosa, CA Member No.: 4,469 Region Association: None |
Here's the description for the L-jet system, page 13. (Would assume it applies for all systems).
L-Jet description Controls the cold start valve. |
|
|
|
| JeffBowlsby |
May 8 2007, 12:03 AM
Post
#5
|
|
914 Wiring Harnesses Group: Members Posts: 8,501 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None
|
"all the Thermo-Time switch does is complete the ground for the Cold Start valve and therefore would not effect starts in 70 degree weather..."
Yep, Uh-huh, javol... (IMG:style_emoticons/default/biggrin.gif) Rich or lean when cold? Have you verified the AFR with a reliable exhaust gas analyzer? Geoff does excellent MPS work, but even a subtle adjustment to the MPS can make a big difference. |
|
|
|
| Bartlett 914 |
May 8 2007, 07:55 AM
Post
#6
|
|
Advanced Member Group: Members Posts: 2,215 Joined: 30-August 05 From: South Elgin IL Member No.: 4,707 Region Association: Upper MidWest |
Make sure you have the correct ECU and CHT. Ones from a 74 will not work correctly. You also need a ballast resistor in series with the CHT. I am not sure of the correct resistance for the CHT for a 73 when cold. I know the resistance in in K ohms (3K, 2.5K something like that). You can always place a pot in place of the CHT. I would use a 5K pot with a 270 ohm resistors in series. Use this to find out if the problem is with the CHT or if it is some other problem like the MPS.
|
|
|
|
| 2-OH! |
May 8 2007, 12:36 PM
Post
#7
|
|
Senior Member Group: Members Posts: 552 Joined: 17-October 03 From: Santa Clarita, Kalifornication Member No.: 1,253 |
Don't know about the Rich/Lean situation because I have not checked it with an analyser...Don't know anyone who has one...But I think that is the problem, Rich/Lean...
I must disconnect the inlet temp sensor to get it to run at all... I agree with the resistor in line with the CHT...But I was under the impression that the Resistor situation was only applicable to the 2.0 motor...I think I have a line on a pot setup and I would like to slave it in to gauge the change in performance... Finished the re-sealing of all vacuum areas last nite and it drives pretty good after 180 degrees...This morning it was better, but still spittin' and sputterin' until I got to work because the 20 minute drive warmed it up... 2-OH! |
|
|
|
| JeffBowlsby |
May 8 2007, 03:27 PM
Post
#8
|
|
914 Wiring Harnesses Group: Members Posts: 8,501 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None
|
Unplugging TS1 richens the mixture, so if it runs better that way, sounds like you may be running lean. Could be berry-berry-bad...check your plugs for a lean condition.
|
|
|
|
| 2-OH! |
May 8 2007, 05:16 PM
Post
#9
|
|
Senior Member Group: Members Posts: 552 Joined: 17-October 03 From: Santa Clarita, Kalifornication Member No.: 1,253 |
Thanks Jeff,
Currently, the ECU is set at one click past the midpoint...I may try to turn it up for the morning start tomorrow and see what happens... New rings are still not broken in yet so we have sooty plug at this point...Hard to read Lean or Rich... 2-OH! |
|
|
|
|
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 12th May 2024 - 07:42 PM |
Invision Power Board
v9.1.4 © 2024 IPS, Inc.