chaseincats

Gotcha, I do have both of those - I didn't realize the vertical one you were talking about was the one that protects the master cylinder @Zed Head No, the prior owner added that a decade ago, not sure why.

can you elaborate a bit on this?

Would I need to remove any exhaust manifold bolts to add it? I'm concerned one or more would break.

Cool, it looks like it is ziptied to the fuel rail

That’s a good question - I know for sure the horizontal one is there but him not sure about the vertical since I do have headers. I’ll check

This is a great idea - I’m surprised Datsun didn’t do this out of the gate. Do you use this?

Can you post a picture when you get a chance?

Post driving update: The car drives great - if I had to guess, the bit of dirt/corrosion on the coolant temp wires had the car run in 'fully warmed-up max lean mode' with a car that doesn't get up to 180...but who knows. My question for you folks is where are you all putting the temp/thermotime bullet connector wires? I popped the hood after driving and these just get cooked in there to the level that the electrical tape glue starts to melt...then will harden again tonight. Granted this is what has been the case forever I guess, but with the new tape/connectors on there, I just noticed it. Is there a place you route them so they get less heat soak or do they just drape over the intake manifold as-is? I used to have them ziptied to the fuel rail but I'm sure that cooked them even more, no?

These are the two shakeables in the car that I’ve found so far that cause it to die: The first is the ecu temp harness connector which somehow even after the car is warmed up leans the engine out further: youtube video here The second is the main ECU power relay. If you knock on the relay bracket, the engine would die. I took that relay out, cleaned its contacts, tightened the internal screw it has to hold it to its metal cap, then to the relay bracket, now you REALLY have to bang on that bracket to get it to die. youtube video here This week I learned 'if your engine doesn't run right, jiggle and bang on things'

I replaced the connectors on the thermotime switch's sub-harness/its oem harness side years ago but left the temp gauge ones as-is and sanded them a bit because they weren't as bad. I'll change the connectors tonight for the temp gauge side regardless, but I don't understand why a higher resistance level/bad connection (which is supposed to richen the engine) caused it to lean out. Basically I'm looking for a definitive thing to point at and say, to quote Al Pacino, "that's the bad guy." Jiggling that wire fixed it, but I don't understand why.

UPDATE: After driving it yesterday and it running lean per usual, I got out and while the engine was running, jiggled wiring and when I got to the connection between the ecu coolant temp sensor and main harness, the car stumbled. After that, it returned to the proper mixture (14.2 idle instead of 14.7) and it drove great/richer throughout the rev-range unlike before. I got home and with a multimeter, noticed that if I jiggle that connection just right, that connection loses continuity. I read that over 176 degrees, the ecu fully leans out the car (the car was fully warmed up to around 170 degrees at that time (I have a 170 degree thermostat instead of 180)). That said, the ECU leans out the car by the temp sensor providing less resistance rather than more to the ecu (my connectors were slightly dirty/loose which would provide more resistance which should have riched it I'd think). I'm trying to figure out why jiggling that connection riched it instead of leaned out the car further. Any ideas?

Hi gang, So I took the car out last night and noticed it's no longer idling at 14.2 but way up at 14.6 - 14.7 and is also weaker once it's in 'cruise mode' (tab not touching the idle enrichment or full-throttle pin in the TPS) than before the shut-off incident even though I hadn't changed anything. In the past, moving the AFM's black gear 1-tooth to the lean side of the original factory position gets the idle to 13.8, turning another tooth (now 2-teeth past original position) gets you a 14.2 idle, and 3-teeth gets you a 14.7 idle. Interestingly, while I moved the black gear back to 1-tooth past original positioning, I get 13.8, but 2-teeth now goes to 14.7 at idle (instead of 14.2 how it behaved in the past when running properly). I popped open the current ECU and nothing crazy jumps out at me (see below pics) damage-wise. That said, I did notice there is some clear stuff (looks like transparent glue) coming from one of the chips and each of the holes that don't have chips soldered through them have some sort of shiny polish to them (boxed in orange on the final two below pics). None of those things I noticed look fresh at all however (something that happened within the past week when the shut-off occurred). EDIT: I remember last night noticing the dip stick wasn't fully in - when I popped it fully in, the car went down and idled at 14.2 for maybe 20 seconds but went back to 14.7 after that. I plugged the hole with my finger just to be sure it wasn't the dipstick's seal or it popping out, but noting changed and sat at 14.7 again so that must have been a fluke. Any ideas?

Good suggestion - I just checked and they're tight and free of corrosion since the last time I sanded them.

Arg, that's not what I wanted to hear haha

Interesting. I wonder if auto used additional sensors like for the full-throttle kickdown function.

Are you talking about the one in the first post on this thread? It looks like the automatics get the 601 ECUs and the manuals get the 600. My car was originally auto and the PO changed it to manual but the 601 ECU is still in there and works. I wonder what the differences really are between them considering the auto ECU works in my manual-swapped car...

Gotcha - unfortunately, there is apparently no way to test them as mine looks brand new too. Pretty frustrating.

Sounds good. If it helps: my ignition module's part number is: E12-27 8328 my ECU module's part number is: A11-601 000 8317

@Zed Head Do you think these two issues (the stumble at speed with the tach needle possibly not moving) and the shut off at a traffic light with the needle not moving could be related? @Yarb @Patcon Any idea if the ones you have work and what you would sell them for if my ECU ends up being the issue? It doesn't sound like there's a way for me to test it.

Is there a way for me to test my ecu? I've opened it before and I didn't see anything suspicious/cold solder joints.

Definitely true. If it helps, the tach needle didn't jump around before it died, or if it did, my eyes weren't drawn to it. This happened idling at a stop light maybe 10 minutes after driving 20 minutes at around 3500 rpm on the highway. If it is the ECU, are all ECUs compatible with a 1978, or do I need one identical to the label in the picture?

@Zed Head I haven't had this issue again, but tonight I was driving, stopped at a stoplight after being on the freeway for about 20 minutes, and the car shut off like a switch was pulled (didn't stumble and die so it would be a spark issue). Could this be related? This is the first time I've had this happen ever. If it helps, I turned the key and it immediately fired right up like nothing happened.

Hi all - One of the louvers on my hood is for some reason no longer laying flat and pulled its front 2 mounting bolts off. I glued them back on with JB weld but feel that if I crank it back down, it will either yank the rear ones out, or crack. I'd have thought if these were to warp at all, it would be the one on the left above the headers, but this is the passenger side one. Am I good to just crank it back down or should I hit it with a heat gun or something? It's plastic so I don't want to melt it.

buy this and you're done: https://zcardepot.com/products/coolant-temperature-sensor-for-gauge-japan-240z-260z-280z#:~:text=$11.99,operates%20the%20coolant%20temperature%20gauge the end - I won’t be responding anymore since you now have the answer and a link to the part you need to fix the issue. Good luck

Ok, thanks for doing the test, now I'll move on - funny how you get a solution when you listen to us, huh. You have 1 test left - this will tell you if its the sensor OR the gauge that need to be replaced. Unplug that yellow wire you took a picture of and ground it against the engine block using an alligator clip/piece of wire/whatever. Touch one end of the alligator clip to the engine block (or any groundable area), touch the other end of the alligator clip to the yellow wire's metal connector, turn the ignition key to 'on', and look at the gauge: IF your gauge is good, the gauge's needle will move all the way right (250+). If that happens, your gauge is good, and your temp sensor needs to be replaced. If the gauge does NOT move all the way to the right it is probably your gauge. Replace the temp sender too though. This is the final test - it WILL give you a final answer.