SilverSurfer

Thanks again for the help. I am not certain I need one ... yet. There are a few things I need to investigate with my 280Z. One is that the tach does not always work. Sometimes it climbs to around 3000 RPMs and just sits there no matter what I do (idle, race the engine, drive, etc.). Other times it seems to work perfectly. I am sure there are several things that can cause this, so I am investigating. The second is the previous own had a red wire that he connected to the fuse box. He did it by exposing the wire and simply wrapping it around one of the ends of one of the fuses in the box. At first, I thought this was to the stereo/CD player (which does not work) as I remember doing stuff like that back in the 70's and early 80's. But I made a discovery quite by accident (since I had not traced the wire). I had pulled the stereo and had already disconnected the wire. When I went to start the car, the starter turned, but the engine just would not fire! I reconnected the wire (on a whim) and went to start the car. It fired right up! I also had another strange thing happen. I had a few blown fuses and was in the process of replacing them. By accident I touched one end of the fuse to the terminal where the wire was connected and the other end to the terminal where I was trying to install the fuse. When the circuit was closed, the car tried to start! WTH? I guess I have a way to start my car if I lose my keys ... I have to trace this wire, but it seems like the previous own bypassed something.

Thanks everyone. I appreciate it. The reason I asked about the difference between a Transistor Ignition Unit Module and the Ignition Control Module is because of this: Listed as a Transistor Ignition Unit Module for a 280Z up to 1977: Listed as an Ignition Control Unit for a 280Z up to 1977: These both look very different to me.

Hello all! I have a 1977 280Z and I want to check the ECU ... but I don't know where it is! Can someone tell me where to find it? Also, what's the difference (and location) between the Transistor Ignition Unit Module and the Ignition Control Module? Isn't the Transistor Ignition Unit Module under the dash on the wall on the passenger side, near the fuse box? Thanks for any help!

Yep. The main problem I was having was the strange angle I had to hold the screw driver at for two of the tabs. I was more hitting DOWN than at a decent enough angle to get it to move. However, I will give it another go.

Thanks for all the info, siteunseen. However, I could not get the ring off, no matter how I tried. I hammered it (using a hammer and screwdriver) and the ring barely turned at all. It was difficult working through the tight space afforded by the hole (once the circular lid had been removed). It's just on there that tight. So, it just might be easier to get this off once I drop the tank.

That's exactly what happens. When the car starts to stutter and stammer (and even if it stalls), I simply have to let it sit for a few minutes. Rarely 5 minutes. Normally just a minute or two. Then the car runs great for a time. As indicated above, the more fuel is in the tank, the longer the car will run between stutters (most of the time). But as the fuel level gets lower, the stammering happens more frequently. When the fuel level is high, stalling almost never happens (even when there is a stammer or two). As the fuel level gets lower, stammering becomes bucking at times, and stalling happens more frequently.

Okay! Here is what I've noticed the past few times I've run the car. I don't know if this helps at all, but I thought I would add it into the mix. When I first put on the inline filter, I had filled up the tank to full. The car ran great for about an hour (on the highway and off). Then, as gas was used over time, I started to run into more and more trouble with the engine starting to run rough ... not continuously, but periodically. The more gas I used, the more I hit these stuttering and stammering spots (including a few times when I stalled out). Since my gas gauge is not working, I am using the tripometer to estimate how much gas is being used. In each case, the troubles start to increase after about 70 miles of gas use. When I get up to 95 or more miles, the car starts to have frequent stutters, especially under load (i.e. on the highway going over 50 MPH). Now, just to be clear, these miles aren't all put on the car at once. I am not driving 100 miles at one time, the car doing great for the first 70 and then slowly degrading as I drive. I am driving a few miles here and there (going to the store, going to pick up a part, going to visit a friend, or just going to take the car out on the highway). Judging by the fill-ups and how much gas I had to put in compared to the tripometer, I am averaging about 15 MPG. So, after using about 5 gallons of gas (from a full tank), I start to get stutters periodically. After using about 6-7 gallons, the stuttering becomes a lot more frequent, making it hard to take the car anywhere. Does this provide any useful information? Edit: Here is something I forgot to mention above - I had filled up the tank twice after the previous inline fuel filter was installed. Both time I did it after running the car for about 90-100 miles worth of gas. Both times the car ran great on a full tank, but started to stutter and stammer more (periodically) as gasoline was used. This last time, I swapped out the inline filter (see images in my previous post above), but did not fill up on gas (I want to run the tank out so I can drop it and clean it). When I ran the car tonight on a fresh inline filter, I almost instantly had issues with stuttering. The car would run smooth at times, but would also stammer at times. Yes, I am planning to get a gauge to measure fuel pressure. I just am waiting for my next paycheck to do so. Then I should be able to provide some additional information.

Part number would help. Once I pull the tank, I'll look at the current sending unit and see if there is anything obviously wrong with it. Once the sending unit is out of the tank, is there a way to test it to see if it is working?

Also, while I am dropping the tank, I might as well take a look at something else - My gas gauge is not working. It moves from 'E' (when the car is off) to about 1/3 tank and sits there (when the car is on). I am guessing that the float is stuck. Is this something that can be fixed? What should I look for once I drop the tank? Or should I just go ahead and see if I can locate a new one?

Thanks, Cliff. My main concern, having not done this before, is dropping the tank. But this just means me reading up on it and learning where everything is that I need to disconnect. I've seen that there are a few good tutorials out there, so I am sure that this won't be that difficult ... just a tad time consuming. I have a little over a half tank in the car now and have installed a new filter. I plan to run the car for a bit, get the gas down a lot more, and then drain it and have at it.

Yep. I am familiar with 'tranny', 'carb', and I am sure a few others, too. But 'dizzy' was new to me. I will learn (and I will ask questions). Yep, the filter was much filthier than I expected. It's been installed for about a month (a little less), but I've only put about 100+ miles on the car in that time. Unfortunately, there is no place near me that does the tank 'clean and coat'. I'll either have to do the work myself or send it off to some place. I plan to do the work myself. Thanks for the link. That will certainly help.

Well, I think we know what the stuttering/stalling issue is with the engine: I replaced the inline fuel filter (between the tank and fuel pump) after only running about a half tank of gas. I definitely need to clean out the tank.

Concerning the tachometer - I had noticed that the tach is not always working properly. Sometimes it seems to get 'stuck' between 2000 and 3000 RPMs and stays there no matter the speed I am going (in city, on the highway, stopped at a light, etc.) until I park and shut off the car. Most of the time it is working and appears to be working properly (i.e. the RPMs seem to be matching what the car is doing correctly). At no time does the tach jump or bounce around.

Thank you, siteunseen! I appreciate it. I do know what a distributor and coil are, I just did not know that the distributor was called a 'dizzy'. Now I do. And since 'dizzy' is used a lot on the forum, knowing what it is will really help me out. For trivia's sake, is it called a 'dizzy' because of how the rotor spins? Or is there another reason?

First of all, thanks for the links and advice. I do appreciate it. I wonder about it being the Transistor Ignition Unit (I had to look up what a TIU is ... sorry ... I am a bit ignorant of the proper terms) failing as it gets warm because the stuttering/stalling issue does not happen when it gets warm. It happens intermittently. It can happen shortly after starting the car (i.e. the car is cold). It can happen within a few minutes of the car running. It can happen 30 minutes into driving the car down the highway. The vehicle is acting more like it is struggling to get fuel than an electrical issue. However, I am not ready to rule anything out. Now, to really show my ignorance here, I need to ask a few things. You say the following: What is the 'dizzy'? What is the 'HT lead'?

Thanks everyone! I was looking at a few of the Konig wheels for my Z, so this all sounds good!

Hello again. Eventually I plan to get new wheels/rims for my 1977 280Z. The previous owner had put adapters on it to go to 5-lug rims. This is a bad idea. So, I want to remove the adapters and go to 4-lug rims. However, the tires are brand new (from when I bought they car) and are pretty nice - Yokohama Advan S.4 205/55r16 ... so I want to keep these tires. 16" rims look sweet on the car, too. From my research, it appears the original bolt pattern is 4x4.5 (114.3mm). When I look for new rims/wheels, is there anything I need to keep in mind other than the bolt pattern (and, of course, the fact that I am getting 16" rims that will accommodate my tires ... 5.5-7.5" wide, 16" rims)? Reading some of the older threads that I ran across (back in 2003, etc.) people were saying that there weren't many wheels that would fit these old Z cars. But a quick Google search seems to show quite a few wheels with the correct bolt pattern. Am I missing something? Also, what about offset?

I am not sure I am seeing water in the filter. I thought I was. I was at an Autozone and a mechanic was there. I asked him to take a look and he agreed that it was water.

Good news! Internal and external turn signals are working! Bad news is I am not sure why, actually. After having the front end aligned, and the steering wheel adjusted (it was a custom wheel the previous owner had installed and was all crooked), the turn signals just started working again. The mechanic who had worked on the car previously (the one that did all the engine work) had also done something in that area because the horn had not been working. I am wondering if something, like a connector, had been lose (and maybe still is) and when they adjusted the steering wheel it knocked it back into place? Dash lights still are not working, but I have not had sufficient time to work through the harnesses, etc.

Thanks everyone! I appreciate the help (and the photo, too, siteunseen). @Patcon - I've only run it through approximately 1 tank of gas. I normally fill up at about a half tank. I've not wanted to take it on a long trip due to the stalling at odd times and I've been quite busy, so I don't get to drive it as much as I like. I plan to rectify that, though. @Fastwoman - Yes, I was thinking that there still might be some water there and perhaps a few pieces of rust particles. There are a few laying at the bottom of the inline fuel filter. @siteunseen - The mechanic had tested the pressure on the fuel line and said it was good. But I may test this if it keeps sputtering after a few more tanks of gas. I was taking the car out this morning and it sputtered and died. I was at a stop light when it started to sputter. I managed to get it (barely) through the light, going no more than a few miles an hour, sputtering all the way, before the Z died. I tried to start it right away and it coughed and died immediately. I waited about 30 seconds, tried again, and it sputtered, but would not ultimately fire. After waiting about 2 minutes, I turned the key. The engine sputtered once, then revved wonderfully. The car has been driving perfectly ever since. I was taking the car in to get new tie rods and a front end alignment. I told the mechanic about the stalling. The tried to get it to stall and it would not. I'll just have to keep an eye on this.

Hello again! I thought I would start another thread about my '77 280Z and it's engine issues. A little background on me: I have done minor repairs such as replacing brakes, tuning an old carburetor, and even pulling a few pistons from an old '55 Plymouth. But I am pretty ignorant when it comes to the inner workings of a car, for the most part, though I am willing to learn. Now, a little about what's going on with the Z and what's been done thus far: When I first got the car a few months back, the car would not run at all. I could get it to start some of the time, but could not keep it running. It would sputter and spurt and then die. Even when it seemed it was somewhat running, applying the gas would cause it to just quit. The car was then worked on by a mechanic and he did much to the vehicle for me - went through and replaced all the fuel lines, installed a new fuel pump and filter, replaced the injectors and pig tails, checked fuel pressure, etc. I had known this mechanic for some time and trusted him, but it turns out he is really good with newer cars (i.e. cars where a computer can tell you exactly what is wrong), but was frustrated with my Z and trying to get it to run smoothly. I got the car back from him mostly running, but it would stall ... a lot. In other words, I could drive the car and it would end up stalling at odd times. It was not heat related as the engine was sufficiently cooled by the radiator, etc., and maintained a good engine temp throughout. The car would purr along ... and then die. Sometimes it would die shortly after starting it and driving. Sometimes it would go for quite some time (15-20 minutes of constant driving) and then it would start to sputter and lose speed, going to a crawl and then shutting off. When the car stalled out, turning the key would not get the engine to run. It would crank, sputter again, and the die. Sometimes it would just crank and do nothing more. If I let the car sit for a few minutes (literally a few minutes ... sometimes only 5) and crank it, the car would start up and drive as if nothing were ever wrong. Since the mechanic did not want to deal with the car any more, I decided to see what ignorant me could do. I purchased and installed an inline fuel filter and installed it between the tank and the fuel pump. I thought that perhaps there was rust in the tank. At least with the clear plastic filter I could check it and see what was going on. The filter seemed to help and the car did not stall for a few days, but then it started to stall again. Looking at the filter there was water in the gas and very little rust at all. I used a bottle of HEET and this seemed to help, but not completely. The car would sputter from time to time, but not always stall out. I fueled up and tried a second round of HEET and the car was running awesomely after this ... for the most part. The car no longer stalls and shuts down. But there are a few times where it starts to stutter. Most of the time it does not lose speed, but just sort of stutters. You can hear that the engine is not running as smoothly and you can feel it as you are driving. This has happened both when I am driving in the city (i.e. 35 MPH) and on the highway (65 MPH). Tonight, however, as I was driving on the highway, it started to stutter and lose speed. It did not die out (dropped from about 60 MPH to about 50 MPH and would not go any faster) and after about 30 seconds of driving that way it righted itself and purred along just fine all the way home. I need to check the filter to see what's going on, but it's dark right now. I'll do this in the morning. But since this is on my mind, I wanted to share what I am currently experiencing to see if anyone thinks they have an idea what is going on. Could something like the ECU or Ignition Control Module be failing or starting to fail (and, if so, could either of these have this kind of effect)? If this were happening to your Z, what would you check first? Please keep in mind that I am fairly dumb about this stuff, though learning. Please spell out things like "AFM" as "Air Flow Module" since I will most likely not know what you are talking about. When I first saw ECU, ICM, and the like, I had to do a search to find out what they were and hope that I was finding the right thing. Thanks again for any help and your patience. I truly appreciate it.

Some small progress on the electrical side of things. I rechecked the fuses and two of them were no good. One was for the hazard. Now my hazards work (both on the dash and outside on the car) as do all of my gauges on the dash (voltage, etc.). However, the actual dash lights do not work nor do the turn signals (neither on the dash nor outside on the car). So, the only non-working things are all my dash lights and my turn signals (internally and externally). All other dash components appear to be working properly.

Thanks again for all the advice. I hope to find time this week and next to actually tackle (and learn) the electrical system. On a side note, the car was still stuttering from time to time and it was not heat related. So, I installed a fuel filter between the tank and the fuel pump. I drove the Z hard today and had no issues, either on the highway or in the city. The filter seems to be helping.

Okay! As I am learning all of this, I went out and purchased a circuit checker (one of the ones that both lights up and beeps) and decided to do a test. I removed the covers to my fusible links, removed one of the links, turned the key to "ON" and used the circuit checker on it, connecting the one end to one 'peg' and touching the other. As expected, the light came on and it beeped. So far, so good. However, when I did the same to the second link, I got nothing. Here is a photo to show you precisely which link (it is the red circled one): I know the set on the right has a ground (the big black link), but does the back one on the left also serve as a ground of some kind? Or should it also produce a light/beep on my checker?

"The light is a warning light. If it's on continuously it's warning you that something is wrong. So, the thing to do is to go to the Brake chapter of the FSM and see what could be wrong. If the brakes aren't bled fully, the light will stay on. If one of the reservoirs is low and you have the sensor caps, the light will stay on. If the parking brake lever is engaged, the light will stay on. That's what I would do first. Heed the warning." My mechanic had just replaced ball bearings (front), rotors, and brakes on the front, pads on the back, and bled everything. Basically everything 'brake' related is new and properly taken care of. So, I am not sure what "warning" to heed here.