Thermo switch and relay

[n/a]

After reading the many postings on the subject, I "cheated" and hot-wired my 1971 280 SL's CSV valve via an ON/OFF 12 V switch in the cabin. So now the car starts in the mornings on the first go. You cannot imagine my sense of accomplishment! (I had NEVER done work on a car before. Took me a few days just to locate the parts on the engine).

By the way, once hot, the engine starts immediately -- I use the pedal-to-the-metal technique.

Still, I'd like to replace both the thermo switch and its relay which, as best as I could figure out, are both shot. Can anyone help me with the part numbers involved?

Next, I will start looking into a backfiring problem that I have noticed when accelerating, particularly when the car is still relatively cold. Any ideas? Might one of the temperature sensors in the block be at fault? Or the "speed relay"? Or both? Where would you recommend I start my research?

Thanks everyone. This is a great group.  

[tuultyme]

Look at posts related to the speed relay on your 71.  I sent my speed relay to Beckman Technology to have rebuilt and now this system work good; I can hear the timing advance about 2300 RPMs.  The PO also installed a hidened switch for the CSV on mine; I do not believe my one second relay works.  Just do not use it when the car is warm.

Bruce; 268Blaugrun(green) 1970 280SL; IL

[jeffc280sl]

Hi Jaime,

Check my post dated Oct 6, 2003.  I describe a simple problem with the cold start relay.  I have a picture and a fix.  I'll bet this is the culprit.  If so, you can do away with the add on switch.  Let me know.



Jeff C.
1970 280SL 4-speed

[hands_aus]

http://index.php?topic=825

Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto