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Thread: 1976 water temperature switch

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    Texan saridout's Avatar
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    Default 1976 water temperature switch

    i need a replacement water temp switch for my 1976, but unfortunately nissan doesn't make them anymore and i can't find any third party suppliers. i noticed that MSA sells a water temp switch for a '74 that looks very similar to mine, albeit with different connectors on the wires. has anyone ever used one of these to replace the switch in a 280? do the threads even match? being that one is from a fuel injected vehicle and the other is not, would they function the same? here are photos of a 1976 switch and the MSA switch:
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    1976 280z Automatic

    my 280z flickr set

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    Registered User darom's Avatar
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    Default

    rockauto.com carries coolant temp sensors. I bought one from them some time ago.

    good luck with your project!
    - 1976 280Z
    - 1967 Camaro RS

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    are you talking about the temperature sensor? what rock auto calls a temperature switch features a photo of a coolant temperature sensor. i need the switch. please look at the photos.
    1976 280z Automatic

    my 280z flickr set

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    remember what part number you used off hand..?? Perhaps this photo might help...like they say..."a picture is worth a thousand words..."


    webdawg1
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    ooooh that's beautiful. i wish i had one
    1976 280z Automatic

    my 280z flickr set

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    saridout,
    I started a thread about this "temperature switch" on Hybrid Z a while back. Here is the link: http://forums.hybridz.org/showthread.php?t=130436. There is a link at the end of the thread which may be helpful in finding a source for this switch (oops, just checked the link, it leads to the same part number that webdawg1 just posted).

    Basically, that switch is used to select which pickup in the dual-pickup distributor is used. I assume it switches from the retarded pickup to the advanced pickup when the engine warms up, but it could be the other way around. It may also have some EGR functionality if your car is so equipped (mine is not).

    If you cannot find a replacement switch you could run without it (you might need to jumper the switch leads to trick the car into using the advanced pickup all the time), or you could convert to a newer distributor which doesn't use dual pickups.

    I got a 1979 280ZX distributor complete with ignition module (part number 31-619) at AutoZone for $105.00, their ordering system says the distributor does not include module but I have bought 2 of them (one for myself and one for a friend) and they both came with modules. Instructions for this modification can be found here if you are interested. http://atlanticz.ca/zclub/techtips/d...tor/index.html

    I hope this helps,
    Steve
    Last edited by YellowFever; 09-16-2009 at 06:14 AM.

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    Former frequent poster sblake01's Avatar
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    It that switch on (continuity) or off (no continuity) at operating temp? If it's off I may have something that would work.

    EDIT: Never mind, I just looked at the switches I have and if the ones posted above are correct, the threads on mine don't match.
    Last edited by sblake01; 09-16-2009 at 06:28 AM.
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    I'm just guessing here, but I suspect the switch on the '74 was to indicate overheating (i.e. for a dummy light). If your engine is cooling normally, the switch would never close. You probably need a switch that trips at a lower temperature than the one you found (i.e. the '74).

    But then again, I don't know much about anything prior to '75.
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

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    Former frequent poster sblake01's Avatar
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    Quote Originally Posted by FastWoman View Post
    I'm just guessing here, but I suspect the switch on the '74 was to indicate overheating (i.e. for a dummy light). If your engine is cooling normally, the switch would never close. You probably need a switch that trips at a lower temperature than the one you found (i.e. the '74).

    But then again, I don't know much about anything prior to '75.
    74? The switch we're talking about was on a 75-76 and was there to select which pickup in the dual-pickup distributor was used, as stated earlier.
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    Texan saridout's Avatar
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    Quote Originally Posted by YellowFever View Post
    saridout,
    I started a thread about this "temperature switch" on Hybrid Z a while back. Here is the link: http://forums.hybridz.org/showthread.php?t=130436. There is a link at the end of the thread which may be helpful in finding a source for this switch (oops, just checked the link, it leads to the same part number that webdawg1 just posted).
    yeah, i've already checked at courtesy nissan, that part is no longer made. :/

    Quote Originally Posted by YellowFever View Post
    Basically, that switch is used to select which pickup in the dual-pickup distributor is used. I assume it switches from the retarded pickup to the advanced pickup when the engine warms up, but it could be the other way around. It may also have some EGR functionality if your car is so equipped (mine is not).
    from what i've been reading (http://forums.hybridz.org/showthread.php?p=1028472), the 74 had the same kind of distributor, which would lead me to believe that the 74 water temp switch functioned the same way. my car is EGR equipped; but to affect the EGR, the switch would just have to signal to it as it's passing through on the way to the ignition module, right?

    i may end up buying the 74 switch just to give it a try. if it works, then it'll be a solution for this problem that other folks can use too. back before i started rebuilding my engine, my car was constantly running way too rich. Could a disconnected water temp switch have precipitated this?
    1976 280z Automatic

    my 280z flickr set

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    Quote Originally Posted by sblake01 View Post
    74? The switch we're talking about was on a 75-76 and was there to select which pickup in the dual-pickup distributor was used, as stated earlier.
    i'm also asking about whether the water temp switch from a 74 might work in a 76. see my photos
    1976 280z Automatic

    my 280z flickr set

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    Quote Originally Posted by saridout View Post
    i'm also asking about whether the water temp switch from a 74 might work in a 76. see my photos
    Oh, that's very different, never mind! My apologies to FastWoman. Does your present switch have any markings on it? Such as, 35-OFF, or something along those lines?
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    while i wait for my dad to inspect the switch on my car for markings, i thought i'd post these ignition diagrams from 1974 and 1976 model. i'm no good with electrical stuff, but it appears to me that the water temp switch in both years functioned the same way. thoughts?

    i am a little confused though, cause i thought that my car was a california car, having an advanced emissions system, but the fsm says that only non-cali models had the water temperature switch. here is the copy from the fms:

    "On the non-california model, the advance control relay and water temperature switch are provided. The temperature switch is a bimetal type. When the engine coolant is at low temperatures, the contact points are close and current flows through the relay, so that the transistor ignigion unit transmits advanced ignition signals. When the coolant reaches and fixed temperature and the bimetal temperature switch contacts are so opened as to not let an electrical current flow the relay, relay contacts are closed and another voltage is applied to the ignition unit, which transmits retarded ignition signals. In this way, advanced signal is changed over by the temperature of engine coolant."
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    1976 280z Automatic

    my 280z flickr set

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    Former frequent poster sblake01's Avatar
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    Looks to me that all the switch does is complete a ground until the temp reaches a certain level then it opens. If the temperature they open is the same then all you'd have to do is splice your 76 connectors onto the 74 wires. It wouldn't even matter if the wires got switched since all it does is complete a ground. These are the ones I have that open at 35 deg. C. I'm just not sure they would fit the water outlet.

    Last edited by sblake01; 09-16-2009 at 10:32 AM.
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    Texan saridout's Avatar
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    maybe it's the angle, but the threaded portion of that switch looks bigger than the switch on my car. do you have calipers? the threaded portion on my switch is 13.45 mm wide. also, dad got back to me with the markings on it. one facet says 509 and another facet says TB-14.
    1976 280z Automatic

    my 280z flickr set

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    Former frequent poster sblake01's Avatar
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    Just measured it and it's just a shade under 17 mm. so, like I thought, they're too big.
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    Don't know if it's any help or not...the switch I have has the following info on it...

    TB-14P
    60-OFF
    another facet has some sort or marking on it and 05 right below the mark...
    next facet over has either 1.1 or 11 on it...(probably 11)


    webdawg1

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    is that from your new N4202 switch?
    1976 280z Automatic

    my 280z flickr set

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    yep...I can check on the old one two...75 280Z...


    webdawg1

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    ok...on the old switch (which I might add was in pretty bad shape) it has...pretty much the same mark on one facet as the new one...503 on one facet...and TB-14 on the other facet...no other marks or info noted on the other facets...


    webdawg1

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    Texan saridout's Avatar
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    Default Update!

    the new switch for a 1974 260 has arrived, and it fits! i tested it on the stove, and it completes the circuit at about 90 degrees. the original switch, according to the FSM (pg. ET-16), closes the circuit at 134 degrees, and that's a difference i can live with.

    i'll let yall know if there are any developments once i actually get the car running.
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    1976 280z Automatic

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    Just wondering if you got it to work. How exactly is it wired? Mine is in just as bad shape as yours. Please advise.

    Jan

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    i'm still getting the engine put back into the car, so i haven't turned it on yet to see if it works, and even when i do, it's likely that there will be no way to tell if it's working. the new switch functions in practically the same way, the only difference being that it connects at a lower temperature (90F versus 135F).

    if you choose to go with the 1974 switch like i have, you'll need to cut off the connector and put a ring connector on one wire that is large enough to go around the nearest bolt that attaches the thermostat housing. the other wire needs to have some more wire spliced onto it along with a bullet connector. that'll connect to a red wire coming off the same 4-prong plug as the thermal transmitter. look here for diagrams http://www.classiczcars.com/forums/s...erature+switch

    note that it shouldn't matter which wire you use for ground on the new switch; they'll both work.
    1976 280z Automatic

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    Default Re:1976 water temperature switch

    While changing the temperature sending unit and cleaning the coolant temperature sensor the other night the two wires literally fell off my water temperature switch.

    Correct me if I'm wrong, but if the switch is closed at cold temps (less than 134 F), then simply leaving the switch broken (open) will only affect the distributor timing/exhaust gas return when the engine is warming up. Am I correct in that once the coolant is above 134 degrees this switch would open and behave just like a broken switch.

    And if I have it backwards, and the switch is open at temps less than 134 F, and closed at temps greater than 134 F, would I be able to simply ground the wire that previously connected the EGR solenoid to the temperature switch? (At least for the time being, until it is properly repaired).

    Link to thread with wiring diagrams:http://www.classiczcars.com/forums/showthread.php?t=30273&highlight=water+temperature+switch

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    Former frequent poster sblake01's Avatar
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    Your link didn't work (for me) but your first scenario is correct. Closed when cold, open when above 134F.
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    I am so confused, i am trying to reconnect the thermal transmitter in my dad's old '77 280z so that the gauge in the dash works. He installed an aftermarket gauge and plugged into the transmitter's port and has the gauge attached to the hood. This is a picture of the transmitter that i was told i needed, it looks nothing like the one pictured above
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    Hi, if all possible could someone with a '77 280z that has all temp/thermal sensors/switches into the thermostat housing attached and working too take a picture ?

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    Justfun13
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    Hey, whoever reads this post further I found the part you need. That's for a 75-76 water temperature switch. You can find the part "22120-N4202" at courtesyparts.com. These guys seem to have the hard to find parts for early Datsun/Nissan.

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    Justfun13
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    Sorry, I just got an email on my order from Courtesyparts.com. that the part is discontinued and there is no cross reference for the part.

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    Received a new water temperature switch to put on my 75 z. Can some one tell me which wire is the ground by telling me if it is the male or female end?

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    as far as i know, either wire can be used as ground. sorry for the late reply!
    1976 280z Automatic

    my 280z flickr set

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    So..... a broken water temperature switch is one that is alwopen? And the only thing affected distributor timing/exhaust/wise would be during the initial cold start up of the car and once temp hits 134 degrees the only function of the switch is no longer used? so is it ok to assume the only negative affects of this switch being broken would be until the car gets to operating temp.? I'm sorry in advance if im just not getting it but there seem to be a lot of dispute over the actual side effects of using a broken water temp. switch.

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    This thread actually changed from the water temperature gauge sensor to the the water temperature switch at justfun13's post #28. The water temp switch is described in full at page EE-26 in the 1976 FSM.

    Basically, if you disconnect it - circuit open - the car will run on its normal timing both when warmed up and cold. The switch is normally closed, to run off of the other, advanced 6 degrees, magnetic pickup coil (variable reluctor) when cold. I am guessing it's to increase the idle speed up a little while cold. Mine stopped working so I just disconnected it and set the timing where it should be when warm.

    In theory, you could install a manual switch in place of the thermostat housing switch and run off either pickup coil.

    The "switch" from using one pickup coil or the other actually happens in the ignition module.
    Last edited by Zed Head; 01-10-2011 at 11:36 PM.

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    Actually, it was always about the water temperature switch. kjphilippona changed it in post #26 and justfun13 actually put it back on topic in post #28......
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    Oops. My mistake, thanks for the correction.

    I didn't mean to besmirch (always wanted to use that word!) justfun13's reputation...

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    The temp. switch is used only in 260Z with the automatic trans. Its function is to tell the TIU to retard the timing when the engine is cold. My temp switch's wire rotted off, and I was informed that since I lived in a mild climate I shouldn't worry about it.

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    Quote Originally Posted by mousemedic View Post
    The temp. switch is used only in 260Z with the automatic trans.
    That is not correct. All the 260's use the temp switch regardless of the transmission type.

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    mousemedic might be going off of what is said in the 1974 FSM. Kudos to him for checking the factory source. It says that the automatic only used the water temp. switch to switch pickups in the distributor. Of course, 1974 is the year of change so it wouldn't be a surprise if the manuals had the switch also, like the 280Zs do (auto and manual), or they added it to the manuals when they went to the big bumpers.

    To correct one thing in mm's post though, the timing is advanced when cold, then goes back to retarded when warm. My guess is it's another idle speed increaser, like the AAR. It's described n Engine Fuel, not Emissions. It seems like a lot of technology for an unexplained effect.

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    Quote Originally Posted by Zed Head View Post
    mousemedic might be going off of what is said in the 1974 FSM. Kudos to him for checking the factory source. It says that the automatic only used the water temp. switch to switch pickups in the distributor.
    I don't know where he got his info from, but the way it's stated it's not correct.

    All 74's used the water temp switch, not just the auto transmission versions.
    On the manual's it was used to control the EGR function.
    On the auto's it was used to control ignition timing, and the EGR function.

    Maybe it's a language issue in the way it's being described? Switch a few words around and look what happens...

    Incorrect - "The automatic only used the temp switch to switch pickups in the distributor." (the auto used it for more than just this)
    Correct - "Only the automatic used the temp switch to control ignition timing." (OK since the manual trans cars didn't change ignition timing based on temperature).

    "The temp. switch is used only in 260Z with the automatic trans." is incorrect on multiple levels since not only did all 74's use it, but on the automatic trans versions it was used for more than just ignition timing.

    All good?

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    Just trying to help people get on the same page. In this case, page EE-27 of the 1974 FSM.
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  41. #41
    Boat Anchor Repairman Captain Obvious's Avatar
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    Quote Originally Posted by Zed Head View Post
    Just trying to help people get on the same page. In this case, page EE-27 of the 1974 FSM.
    I've got no problem with that page except that it isn't the whole story. There's more to it than that.

    Take a look at EC-16 and you'll see that the same switch and the same relay also controls the EGR function.

    And that EGR control happens on every 260 regardless of what transmission it has.

    Still not sure? Study the wiring diagram. It's there too.

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    I think that you're mistaking my quest for clarity and knowledge with a challenge to what you're saying. It's not. It's exactly what I wrote and the picture I posted.

    mousemedic said "only", I showed why he might have said that. Now, you have shown, with your references, that there's more to the story.

    This is the internet. The best way to get someone to believe the point you're making is with examples and references. Without those, how do you know if anyone really knows what they're talking about? And how do you explain it to someone else? "A guy from the internet said it was so". Thanks for the link to the EC section. Now we're learning.

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    I got no beef here. I just thought the whole thing was a little weird... Out of the blue, mousemedic resurrects a year and a half old thread and posts incorrect information about 260's when the original thread wasn't even about 260's in the first place. ???

    I wasn't going to add anything more after my original post unless mousemedic came back and asked a question. I was expecting the whole thing to go back to sleep. I just didn't want it to go back to sleep on an incorrect note. I suspect that detailed discussion about the 74 temp switch in a "1976 water temperature switch" thread is likely to get passed by in the future. Probably best suited to a different thread with a more appropriate title.

    Quote Originally Posted by Zed Head View Post
    I think that you're mistaking my quest for clarity and knowledge with a challenge to what you're saying.
    Sorry. Yes, I did. It's because you asked no questions questing. It was all statements stating.

    But if you're questing, I'm no expert, but I'm happy to do what I can to provide clarity and knowledge:

    The 74 manual is admittedly obtuse when it comes to the temp switch. I've found the switch is described in multiple sections "functionally" instead of all in one place showing all the things the switch does. The only single source that I've found that shows everything in the same spot is the wiring diagram itself.

    The 74 switch is open circuit when cool (below 77 degrees F) and closes when warm (above 88-106 degrees F). It has two connections, one to ground, and the other to the "EGR Relay". When the switch warms up, it energizes the coil of that relay. Note that different years switches operate differently.

    On the wiring diagram, the water temp switch and the EGR Relay that it controls are both in the lower left corner. Note that there's a grounding mistake on the black wire from the temp switch (missing dot) on the diagram - Nothing connected to the temp switch would even work at all if the car were actually wired as it's drawn. The driver's side turn signal and marker lamp wouldn't work either.

    The EGR Relay has two sets of contacts. The N/C contacts start closed (when the engine is cool) and go open when the engine warms up which enables the EGR system. The N/O contacts start open (when the engine is cool) and go closed when the engine warms up which (on the automatic transmission cars only) switches the ignition timing from advanced to retarded. The manual transmission cars have all the same wiring to the ignition module, but use a different ignition module that ignores the timing change signal.

    I do not believe there are any other connections on the wiring diagram to anything involved with the temp switch and/or the relay that it controls. In other words, I believe the ignition timing and EGR functions are the only two things that the temp switch can possibly affect.

    All 74's used the water temp switch, not just the auto transmission versions.
    On the manual's it was used to control the EGR function.
    On the auto's it was used to control ignition timing, and the EGR function.

    If you were to use a manual trans ignition module on your auto car, your timing would be fixed to the advanced pickup.
    If you have a manual trans car and have removed the EGR valve, then the water temp switch and the EGR relay are both doing absolutely nothing.

    As before, I'm no expert, but I'm pretty comfortable with the 74 and the temp switch. I've been through the manual, I've studied the wiring diagram, I've tested the switch, I've tested the relay, I've redrawn the whole circuit in a form that makes more sense to me... And even after all that, it's still certainly conceivable that I've missed something and I'd be happy to hear about it.

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    Quote Originally Posted by Captain Obvious View Post
    I got no beef here. I just thought the whole thing was a little weird... Out of the blue, mousemedic resurrects a year and a half old thread and posts incorrect information about 260's when the original thread wasn't even about 260's in the first place. ???
    That pales in comparison to his opening up a 9 year old thread to imform three of our Australian members of something they werent actually discussing. The most recent visit from any of those three guys was in September 2010.........
    http://www.classiczcars.com/forums/s...ht=#post401954
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    Haha! Exactly!! I saw that too when it happened and almost said something about it.

    "Holy Zombie!!! Ummmmm... You know this thread is like ten years old, don't you?"

    Instead, like you, I just hoped it go away (again).

    Same thing is happening on other forums as well...

    I was originally thinking padding his thread count, but that doesn't seem to be the case...

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    I need to learn how to use them emoticons.

    A lot of good information here anyway, as a result. I didn't know that the 260Zs were using EGR, it didn't show up on the Federal 280Zs until 77 or 78. I guess the EFI let Nissan back up a few years. Plus, the whole argument about not needing the switch if you don't need the extra distributor pickup becomes less relevant since the switch is used for EGR.

    No harm, no foul

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    Quote Originally Posted by Zed Head View Post
    No harm, no foul
    Absolutely!

    I'm about out of time at this instant, but when I get a chance I'll port that 74 info over to it's own thread. I've been involved in a few discussions on the topic before, but I've never seen all the info in the same place at the same time. It would probably be helpful to 260 folks to remedy that.

    I know the 74 OK, and I'm working on digesting the 77. Everything else before and after? Not my department.

    Haven't thought about it in a while... Thanks for the refresher!!

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