tooquick260 Posted June 1, 2013 Share Posted June 1, 2013 What is the specific job of this switch on a 74 260z? What does it do for a 83 280zxt? I have an ECU from an 83 in my 74 260z. Is it part of the cold start up? What part does it play in the running of the car? I know I don't need it, but when my car is gets to a point of warming up the rpms drop about 150 to 200 rpms is this because of this switch? Quote Link to comment Share on other sites More sharing options...
Domzs Posted June 1, 2013 Share Posted June 1, 2013 Thermal time switch is part of cold start operation which controls your cold start injector . 83 ZXT does not have cold injector . Check your air regulator valve operation . Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted June 1, 2013 Author Share Posted June 1, 2013 I don't have a air regulator installed. Using an N42 intake with everything blocked off. so, why does a 74 datsun have a thermal switch? Car came with manual choke, no-fuel injection to deal with? Quote Link to comment Share on other sites More sharing options...
Domzs Posted June 1, 2013 Share Posted June 1, 2013 I don't have a air regulator installed. Using an N42 intake with everything blocked off. so, why does a 74 datsun have a thermal switch? Car came with manual choke, no-fuel injection to deal with? Good question . Are you talking electric or vac. thermal switch ? Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted June 1, 2013 Author Share Posted June 1, 2013 Must be electric, on my 260 coolant housing it is the switch next to the coolant gauge sendor. Quote Link to comment Share on other sites More sharing options...
Domzs Posted June 1, 2013 Share Posted June 1, 2013 Not too sure about carb Z . Check with FSM . IMO , you don't need any cold start system where you're at , hot enough there , same as Texas . LOL . But with ZXT turbo setup , ECM needs temp. input for fuel control . Quote Link to comment Share on other sites More sharing options...
cgsheen Posted June 1, 2013 Share Posted June 1, 2013 The thermal switch on the L28ET is there solely for the "hair dryer" - the injector cooling fan. Has absolutely nothing to do with engine operation. If the water temp is above the "set point", the switch is made and the controller / timer for the injector cooling fan comes to life at engine shut down. Then it blows air over the injectors (and manifold) for 10 or 15 minutes, then shuts itself off. "Vapor Lock"... The thermal switch on early Z's has to do with timing and advance IIRC... But, he's right, it's in the FSM for the '74. ... when my car is gets to a point of warming up the rpms drop about 150 to 200 rpms is this because of this switch? No. That's ECU and the CHTS. The ECU will always raise the RPM on a cold engine. ~700RPM warm - ~900-1000 cold... Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted June 1, 2013 Author Share Posted June 1, 2013 Dang CG.... should have just sent you a private message. So the drop in rpm comes thru from the CHTS! Get my turbo back on Monday all fixed no more leaking seals and new vanes,,,YAHOO time to drive! Quote Link to comment Share on other sites More sharing options...
cgsheen Posted June 1, 2013 Share Posted June 1, 2013 Well... The RPM comes from calculations the ECU makes (and/or values stored in it's base map) with the info from the temperature sensors and the CAS. The CAS is it's "tach" as well as engine position sensor, and it's monitoring intake air and engine temp through the other sensors. With a clean manifold, you'll probably run rich at idle with the stock ECU. It can't seem to throttle down the injectors enough on it's own at idle. That's why the Air Bypass and AAC - it seems to need additional air at idle to lean it out... Unfortunately you can't "tune that out" with the stock ECU. Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted June 1, 2013 Author Share Posted June 1, 2013 I can see a Z31 ECU in my future. Seems to be the least expense. Martin over in Tampa with Z-Fever says he will do a flash tune for me when I install it. He does the Enthalpy pronged chipped tunes. Martin did the last tune on my 240sx before it was stolen, he said he is willing to due a charity tune because of my loss. I think I am going to skip the Mega for now. Gathering parts for the Z31 stuff as it comes around. CG, since I am not running any of those AAC and Air Bypass, should I run a little higher idle to give more air for the rich idle? Or is that going to give it too much false information? Quote Link to comment Share on other sites More sharing options...
cgsheen Posted June 2, 2013 Share Posted June 2, 2013 No clue buddy. I'm not that smart... Lot's of people here run early EFI manifolds on their L28ET. I don't. But you can search these Forums and ask around. I'm betting most of them aren't still running the stock ECCS though. Quote Link to comment Share on other sites More sharing options...
Professor Threadkiller Posted June 7, 2013 Share Posted June 7, 2013 What is the specific job of this switch on a 74 260z? It disables the EGR system until the engine warms up, and also controls the ignition timing on the auto trans cars. http://www.classiczcars.com/forums/electrical-s30/46647-water-temp-switch-what-does.html Quote Link to comment Share on other sites More sharing options...
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