Jump to content

IGNORED

L28 sensors


Recommended Posts


The one at 11 o'clock is the all important coolant temp sensor that tells the ecu how much fuel for the injectors.   The big one at 2 o'clock is the thermotime switch which tells the cold start valve to add fuel and richen the mixture when ambient temps are low at startup.  The single pin one at 6 o'clock is the temp sensor for the gauge in the cabin.   You can easily test all except the themotime with a vom reading the resistance at a certain temp and referencing the factory shop manual guide. 

  • Agree 2
Link to comment
Share on other sites

4 hours ago, S30Driver said:

The big one at 2 o'clock is the thermotime switch which tells the cold start valve to add fuel and richen the mixture when ambient temps are low at startup. 

 

5 hours ago, S30Driver said:

You can easily test all except the themotime

Test this one in a pot of water on your stove, start with cold water and slowly make it hot.. at one point you should see the sensor switch.

Link to comment
Share on other sites

The crusty one on the side is probably a switch.  Nissan used a variety of combinations of switches over the years.  Without the year of vehicle and engine a person can only guess.

  • Agree 2
Link to comment
Share on other sites

S30driver - they're 14 inch Campagnolo wheels. I purchased them new in the early 90s from the late Al Costintino (sp) the US importer.  Manufactured to a high standard and complete with Campy lug nuts!

That sensor, the one on the side by itself, didn't appear in 77 or 78 - with or without factory a/c.

Link to comment
Share on other sites

14 minutes ago, zspert said:

That sensor, the one on the side by itself, didn't appear in 77 or 78 - with or without factory a/c.

I agree. I have seen it mentioned as a thermo switch for the airco in other threads, but I can't find anything about it in the AC wiring diagram. My 280Z has factory air and doesn't have the switch.

Maybe @ennisdavis can tell us which L28 he is refering to. Could be something ZX....

Link to comment
Share on other sites

I browsed through a bunch of carpartsmanual pages and only found one drawing of the thermostat housing, in EFI Control.  It does show a side port but I can't find a switch defined for the hole anywhere on the other pages.  The carparts site is setup in a way that you have to know something's purpose before you know where to find it on the site.

http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/e-f-i/control

image.png

Link to comment
Share on other sites

Posted (edited)
  1. water temp switch on my 75 Cali car was for the EGR system. It is disabled during warm up with an electrically controlled vacuum source. I have had a few of both the thermotime as well as the temp switch. Most of the used ones did not function. I presume corrosion was the factor. The temp switch in my case was a NC below 140f IIRC, I ended up making my own with an old housing and a new temp controlled reed style switch, epoxied into place. I think the main problem I had finding a new temp switch was most were NO at below 140f and would close once the engine would warm up. Not what the EGR wanted.

I think on others the temp switch had to do with switching the dual coil distributer pickups for different advance one full temp was achieved.

Edited by Dave WM
Link to comment
Share on other sites

Thanks to Zed Heads work I found it in the carpartsmanual - cylinder head section, but little info about what it does.

Thanks for the EGR info Dave👌. I was looking towards ZX, but should have been looking the other direction.

 

Screenshot_20220516-073025.jpg

Screenshot_20220516-073054.jpg

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.