Ownallday

Where is the resistor located for the 78 280z Tach? I don't have my voltmeter to check at this time but would like to see if bypassing it does anything if possible

Okay so I traced out this TIU and found this Going to assume this is the TIU as it had six pins on it. I disconnected it, went for a drive and same results. I can confirm that with this box plugged in or unplugged my rpms only work above 2000rpms. Anything below that my Tach is dead. The blue wire is hooked up to the negative terminal on the MSD coil.

Ouch, here I was under the impression that I was upgrading since I know the ZX distributors are a popular upgrade to those swapping over to Triple Weber's like I just did. So basically I should swap back over to the stock 280z Distributor and pray my tach works or I can replace the ICM and hope I get one that isn't bad quality. I'll do some researching.

So replacing the Ignition module solves the problem? I can't see the issue being anything else since the tach was working perfect before this switch. I believe my issue is similar where my tach only works over a certain rpms.

This is why I am confused why mine stopped working. I did not mess with the TIU, as a matter of fact I had to look it up just to see what it was When installing the ZX dizzy I followed this exact guide. Only difference is the 1978 280z does not have a ballast resistor

Is the resistor somewhere along the passenger side? I can test it tomorrow but the tach was working perfectly before

Hello, I just recently ditched the Stock FI system on my 1978 Datsun 280z and went over to Triple Weber's, with it I also upgraded to the 280zx distributor with the E12-80 ignition and upgraded the coil to the MSD Blaster Coil 2. Car started up like a dream considering they are brand new Weber's and haven't been tuned. However my Tachometer stopped working properly. Either it doesn't work or it somewhat jumps around sporadically while driving. Am I missing something?

So thought I would update this post with the issue and fix for my problem (since I hate finding posts where the author doesn't include the fix). As all the members who posted before stated, the bearings were the issue. I will post some pictures of the transmission after I pulled it out, you can see the bearing in the casing is completely missing (shredded apart) most likely causing the shafts to not be balanced with 1st and 2nd gear. You can see the shaft isn't straight with the other one and bearing is completely missing New bearing in the housing while old bearing is right below it Here is the transmission put back together with all new bearings and synchro's with the rebuild kit that zcardepot provides. The shafts rotate smoothly now with the gears compared to when I removed the transmission. Needless to say, can't believe I drove the car for almost two years like this and even a day at autocross. I would baby 1st and 2nd gear trying to stay out of those gears during the years I drove the car so maybe that helped but however I am shocked I still have a transmission and no other damage was done. Thanks to everyone for the help. I can gladly pound through all gears now with confidence.

Did not know that. I was going towards MSD everything in terms of the ignition system however in general. My big question is how much of a power jump difference will there be between webers and efi itb setup and without a doubt the efi will probably be more reliable overall but by how much? My plan was either TEP or Datsun Spirits setup. TEP is nice because they are 20 minutes from my house so as long as they don't go out of business I think I should be good. And yeah I know it's a big jump, I figured better to just finish everything in the engine bay rather than work one by one constantly taking things off like I have been for the last two years.

Wanted some insight for my future build with the L28, I plan on getting another P79 Head (Previous owner practically screwed the studs for the exhaust manifold closest to the thermostat so I have produced a lovely leak overtime with the annoying clicking sound that sounds like valve slap) The head will be sent out to be rebuilt and built by topendperformance, I do not plan on building the block (I park the car on the street, don't have tools to pull the block) but I do have the N42 Block for reference I want to get the new head fully built as possible as I want to push the most power out of building it. Also will be getting new MSA 6-1 TBC coated headers (will header wrap them) I am sure my pacesetter headers are warped (They look beat up too and recommend to not add header wrap, I want less heat) MSD ignition system and Ignition upgrade, radiator upgrade, trans rebuild with a lighter flywheel And last but not least the part I am unsure the route I want to go. topendperformance sells both Triple Webers and Fuel Injection ITB systems (they even tune both systems and have a dyno) The Webers is a little above 2k for everything, while the ITB setup goes for around the 4k-5k mark. My question is how big is the difference between the two systems in terms of power and reliability? Is the almost 3k price difference really worth it? I have a friend who has many issues with his home built 2.9L 45 weber setup and another friend who has not had a single issue in over 6 years with his stock L28 40 weber setup (his webers were tuned by topendperformance also) Also how much power should I expect from this build? I really want to achieve 250hp at the crank

Interesting, I guess when it comes down to inspection I will inspect the synchros and see if they need replacing based on condition. The car shifts like a champ in all gears but reverse can be a little stubborn sometimes. I give those threads a look at. I will be doing the rebuild at my job at Toyota so I believe I will have all the tools needed, any specific special tools?

Good to have a second opinion, will the kit from zcardepot have the bearing cage, unsure as they don't state it. I will being doing the rebuild at my job, I work as a technician at toyota so I should have all the tools needed as I don't have the luxury of being able to do a job like this at home so work is my only option which limits me a little. I am fine with taking the risk on rebuilding without inspecting. I am very shocked my car still drives the way it does, hell I have even ripped it many times in the canyons. I will update this post or make a new post in the future when I get to that point

Thank you, had a feeling it was a bearing, do you know if the kit from zcardepot comes with this specific bearing? I am okay with doing a trans rebuild and testing my luck before purchasing a new 5 speed, mainly because I will not able to do the rebuild at home.

Okay so my 1978 280z has a 5 speed transmission (not sure what year), has always made noise in 1st and 2nd gear when not pressing on the throttle (kinda soundings a little like a grinding and maybe whining noise). When the clutch is pressed in, no noise, if I am on throttle, no noise. Only makes noise 1st and 2nd gear when coasting (no throttle applied) and you can kinda feel it not coasting smoothly but once again only in these two gears. Based on the symptoms and pictures I provided, are my bearings or synchros bad? Asking before I pull trans for rebuild with the rebuild kit from zcardepot or if I should just buy a new trans since I am unsure if a rebuild will solve this issue

Good to know, thank you! I will check this out I checked two pins but I might've checked the wrong ones is what I'm saying. Okay good to know so no harm changing the sensor then. It was only $20 anyways. I'll be attempting to smoke out for vacuum sunday. Yes I know, Datsun spirit makes a nice kit and sells two different engine management systems.

Yeah, I refered to the FSM (kinda) which is why I bought a new water temp sensor (I'm sure my car needs a new one anyways). Does a faulty temp sensor cause these to run rich only or can it cause the car to run lean too? The last thing I wanted to do was replace parts on this stock efi I would like to upgrade to ITBs by the end of the year. Im pretty sure I might've checked the two wrong pins however, now that I think about it the readings were off. I know my water pump isn't leaking (I check every month for leaks and loose bolts) and just checked right now it's as sturdy as can be, zero play. My harmonic balancer does need replacing though. Quick question, I have one exhaust manifold stud that snapped off towards cylinder 1, (getting this fixed next week) can this cause a vacuum leak and a noticeable decrease in power?

I owe @S30Driver and @siteunseen an apology! Even though me and my friend didn't touch those two connections, one of them came loose and fell off somehow! When plugging it back in I notice the connection is a little lose so I crimped it a little to help hold it in better! Thank you so much to everyone for the help. After plugging the wire back in I was also able to adjust the idle after plugging the wire back on. Drove the car for 10 minutes with no signs of hesitation or bogging even with the tps connected! And I also no longer have to keep adjusting my idle by the looks of things. As a matter of fact the car feels so much faster than before! I really wanted to get this car running asap because she is going to see some autocross action for the first time in 3 weeks. Here's a video of it running after plugging in the connector. It was running lean before I did all the work then started running very rich after at least what my spark plugs indicated! I always put tape on my spark plug wires and number them before taking them off, just a habit I got into.

Here are two videos of my issue.

I was going to check and readjust the valves sometime this week when I get the chance. Not sure how fuel can be the issue out of nowhere especially after a fresh fuel filter. I am trying to get my hands on a fuel pressure gauge hopefully the end of the week. And I plan on posting all the numbers most likely Friday or Saturday when I get more time to work on the car and I will list the numbers to each pin. The car was completely stock prior to my issues (besides unclogging the temp housing line). Deleting the vacuum lines didn't change anything. The part of the car that got removed really was the cold start lines which isn't necessary for me living in LA and the temp housing vacuum line (which once again was clogged before and car ran fine). If you believe it really makes a difference though I will put everything back on. Lol no shop rags missing but I will check into the AFM more when I get a chance. I really want to avoid touching the AFM though. I have tried looking for vacuum leaks in the general afm area and all over the intake but I used the carb cleaner trick (not sure how effective it is). I will give your option a try and see what I can get. Me and my friend never removed these wires only the connectors to the sensors themselves

Forgot to mention that I already dug into the FSM and EFI Bible (which is what lead me to buying a new water temp sensor) I've have also don't a test on the pins for the ECU that lead to the two sensor (which turned out to be good) but I didn't check the others which I'll do tonight. I do have a two other ECU (that I know work) that I'll be trying on the car tonight incase I'm missing something. And sorry I didn't really know any other way to explain it but I removed vacuum lines and plugged them up based off another popular forum. I mainly did this because of the clogged line that me and my friend unclogged. Based on other forums the car should run perfectly with what I removed. Later tonight I'll take a video of my issues and certain test to show a visual and audio explanation of my issue. Thank you, I already tested the pins but I will retest tonight and update

This is one of the possibilities I also assumed. I have a new water temp sensor coming this week. But I don't understand why the sensor would get effected from welding near it. The housing was off the car when I was welding. I have already gone through the fsm which is why I ordered the water sensor. I've already thought of this lol. My two connectors however won't let you switch up the water temp sensor and the thermotime sensor so you can't even switch it up on my car.

I'm going to try an provide as much information as possible. I've had my 280z for about two years now and for the most part has driven very good besides having a high idle most of the time and constantly having to adjust the idle screw in the mornings to raise the rpms then lower rpms after driving car for awhile. I live in California LA btw. Recently I did a good amount of work to the z Last week me and my friend replaced the spark plugs, readjusted valves, installed a new fuel filter and fuel line that connected below the fuel filter, new upper coolant line and coolant. Now the other thing we did was my car had a broken temp sensor stuck in the thermostat housing since I got the car. We finally were able to remove it by welding on a bolt to it multiple times. We also noticed which looked like a line for the coolant to go through was completely clogged in the housing. We unclogged it and reinstalled everything. The temp gauge finally works!!! BUT not so much my car. Upon starting the car it started and idled like a dream. It sounded very healthy. However upon revving my car before taking it for a drive, it bogged and the idle just dropped. Car would constantly do this, upon inspecting the spark plugs, the car seemed to be running very rich (btw my previous spark plugs indicated my car was running lean). So after all this work my car randomly starts to go from running lean to rich? what gives? I was able to driving the car a couple times after cleaning the spark plugs and deleting one vacuum line but the problem comes back. There was even a point where smoke was coming out the tail pipe but it only happened once when I had to over rev the car moving very slowly. Today I can't get the car to move but I can get it to turn on. At first it seemed like the issue was only when the car was warm but then I noticed it would just come randomly. Recently I have done a Vacuum delete (including a delete for the thermostat housing line I unclogged where coolant comes through since I thought that was the issue but this didn't correct anything) I checked and I have no vacuum leaks anywhere either. Currently I can turn on the car and the car will idle around 700-800rpm and adjusting the idle screw no longer does anything. If I try an rev the car it struggles to even rev or rpms just drop. So I can't even move the car anymore but earlier today after the vacuum delete I was able to drive it around the block then it started to bog again after 15 seconds. If I disconnect the Thermotime sensor and the TPS sensor the car turns on a lot easier and sounds like it idles a lot nicer and I can rev the car just fine but if I try an drive it like this the car instantly dies. Oh yeah, my temp gauge does not work anymore either after unplugging it like two times to see if the would solve anything. The car drove perfectly before this so what do you guys think the issue could be?