SilverSurfer

I have not. I am not a mechanic, so can you point me in the right direction to check for vacuum leaks? I am pretty sure I can check the fuel pressure by hooking a gauge into the nipple (don't know the proper term here) on the fuel rail. Is that correct? When I first got the car, it was stalling a lot. I took it to a mechanic I trusted. He ended up replacing all the fuel lines and vacuum lines. The rubber part that connects the AFM to the rest is also brand new and everything is tight. So, I don't think there are any leaks. The car also has a new fuel pump and filters. In any case, why would there be such a big difference between the two air flow meters?

Hello! I have a 1977 280Z stock 5-speed manual transmition. The original AFM seemed like it was having some issues. The engine was running rich (you could smell it and I was getting horrible gas mileage), at idle the engine did not run steady/consistent (it revved up and down sort of like ooooOOOOooooOOOOoooo ... if that makes any sense ... and the tach would move with it below 1000 RPMs to slightly about 1000 RPMs), and, lastly, sometimes when going slow in third gear the car would hit a point where it would jerk until you either sped up or slowed down even further. I had a spare (used) AFM and swapped it out today. The first thing I noticed is the car idled smoothly/evenly right about about 1000 RPMs. This is the best this car's sounded since I've had it. So, I took it for a ride. That's when I ran across a different problem. The car seemed to do great when driving in the city (no jerking when running slowly in 3rd gear), but I ran into a problem when I went on the highway. The entrance ramp I was using is slightly steep (uphill) and the car chugged (moved sluggishly). I could barely get 'er over 35 MPH and so I could not get up to highway speed. Once on the highway I was able to get her going, albeit slowly. Once up to speed, she had a lot more pep. I am assuming that she is now running a tad lean? But I am no mechanic. Not by a long shot. Obviously the new AFM made a difference, solving a few issues and introducing a new one. So, where do I go from here? What should I check? And how do I tweak this? Any help would be appreciated. Thanks.

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? 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.

Well, I replaced the inline fuel filter (the one between the tank and fuel pump) and this is what I found (and after only about a half tank of gas!): I would say I definitely need to clean the gas tank.

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.

I have. None of them in my area (Roanoke, VA) do the work any longer. I either will have to do the work myself, send the tank out to a place that still does it, or get a new tank. I think I will opt for the first option. There seems to be plenty of tutorials on how to do this.

Hello steve edrington. Thanks for your help and advice. I appreciate it. Yep, I need to get the tank cleaned and sealed. It's next on my list (next to finding someone local that can/will do the work! They seem to be getting rarer ... at least in my area).

Hi Seattlejester, I had mistyped earlier. The rust is not in the fuel filter in the engine compartment. That is a metal fuel filter and I cannot see what is in it. What I had meant was there is a small amount of rust flakes in the inline fuel filter that I installed between the gas tank and the fuel pump (the fuel pump is in the rear wheel well, as it should be). This inline fuel filter is of the clear, plastic type, so I can see what is in it. The spark plugs were replaced by a mechanic and the distributor checked. When the car is running, which is most of the time, it runs very smoothly. In fact, I had taken it out on the highway and, when no one was around, ran her up to 100MPG with no issues ... the Z still wanted to pull with no issues. It purred along smoothly as all get out. No shaking. No stutters. So, I don't think there is an issue with the spark plugs being swapped, etc. When I get a chance to install a pressure gauge and to crawl under the vehicle to check the fuel pump part number, I'll let you guys know what they say. I live in Virginia. It has been both cool and warm (near 90). Today has been very cool ... low 60s and overcast. I took the car out and it ran fine, then stuttered and stalled. The car would not restart, but stammered. I waited about a minute and the car fired right up and ran the rest of the way home with no issues. This is the same behavior it can have on a very hot day, so it does not seem to be temperature related. If I run the car at idle for a while, shut it off and then start it back up again, it starts up just fine. No issues here. The only time starting the car is an issue is if it stutters and stalls out. Then it just needs to sit for a moment and then it starts just like there were no issues. To me, this seems like something is interfering (rust or water) and letting it sit for a moment allows whatever it is to settle to the bottom or move on, etc. I plan to run through this tank of gas, fill it up, and apply some more Heet and see where that takes me. If I get a chance (whether permitting before things get too hectic here), I will try to drop the tank (before filling it up) and see what we have. I've never done this before (dropped a tank), so this should be a bit of an adventure.

Thanks, Phantom.

Sorry. That was my mistake. I meant FUEL FILTER not pump. The fuel pump is indeed in the rear wheel well.

Hello SleeperZ. I already have performance tires for the 16" rims, so this is not an issue for me. The converters push the wheels/tires out quite a bit. This can cause issues with the tires possible rubbing on the fender when at a sharp turn. As importantly, it adds a vibration at certain speeds. I had this tested when I had the front end aligned and the mechanic said he could not get rid of the vibration (at certain speeds) as a result of the adapters.

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?

Thanks, seatlejester. I will try to respond to each point with what I know. While it has misfired once that I am aware of, the car stutters when it loses speed. It sounds and behaves like a car running out of fuel. The vehicle has had all new fuel lines installed, a new fuel pump (the one in the engine compartment), new injectors and new pig tails. So, I don't think it is anything in the actual lines (i.e. varnish in the lines). But there is a small amount if rust in the inline filter. Once the ground is dry I am going to swap out that filter for another one (I keep a spare in the car). The vehicle has all new spark plugs. I've not tested the coil. The volt meter on the dash is staying consistent (about 15) when these episodes happen, from what I recall, though I will pay more attention the next time it happens.

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.

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. A 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.

Found out that line apparently connects to the headlights and no current is going through it, even if the key is turned on, unless the headlights are turned on. 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?

Alright! Back onto the electrical issue with limited time this week. I took the back panel off (the plastic cover you need to remove to gain access to the back lights and all the wires there). I checked all the wires, the ground, the connectors and bulbs. Everything looks good. So, now it's on to other things. As a reminder, the following is NOT working on the dash: - Turn signals and hazards (neither are they working externally on the car) - The oil pressure gauge - The volt meter - The clock (though I don't think that was working before the dash lights went out) The following is what is working on the dash: - The speedometer (of course) - The tachometer - The temp gauge - The fuel gauge (though the float in the tank gets stuck at 1/3 tank even on full) Other things work like: - The fan for the vent - The center dash light (the one you flip down to turn on) - The fasten seat belt light and buzzer - The bright, red brake light at the bottom of the speedometer (in fact, for some reason this is on continuously) I don't know if any of this information helps to pinpoint what could be the issue, but I thought I would post what I know so far. Again, I am learning about electrical, so any help would be appreciated.

@SleeperZ - Yeah, I saw that. The guy at the parts store did not seem to know what he was talking about and could not clearly explain to me what he was seeing in the report he was getting.

Concerning the car stalling out issue: The issue to me (and I don't know anything, really) does not seem to be temperature related (i.e. the car running too hot, vapor in the gas line, etc.). Not any more. I've run the car for an half hour, in city and on the highway, and had no issues ... and on a hot day (near 90 degrees outside). Then there are the times that the car is running for only a few minutes and she starts to stutter and stall. If the car is running for a while (30 minutes, etc.) and then stutters and stalls, I only need to let it sit for about 5 minutes or less, and the car starts right back up again (in most cases). The way the car stutters, it is acting more like rust or other junk is clogging the filter from time to time.

Alright! Used a voltmeter and it shows the following when connected to the battery terminals: Car off: 12.8 volts Car at idle: 12.8 volts Car under load: 14.8 volts (sometimes getting up to 14.9) "Car under load" is the lights on, fan on high, and engine revving up to between 2000-3000 RPMs. As I release the gas pedal and the RPMs drop, the volt meter's reading drops. So, it looks to me like the alternator is doing it job.

Thanks for letting me know. The alternator that is currently on the car looks almost new ... and the person who checked it at Advance Auto did not ask me to rev the engine, so it was at idle. I'm currently reading through the 1977 280Z factory service manual found here: http://www.xenons30.com/reference.html But I have to admit that the electrical side of things is alien to me. It's just not something I've dealt with yet. Guess it's time I learned.

Thanks. I am an electrical idiot, though I am willing to learn. I'll have to look to see where the external regulator is. I would not get an alternator from a parts store, but had planned to get a refurb, NOS, or one off another 280Z that was known to be in good working order. As far as using a multimeter and taking measurements, I have never done this and would not know what I was looking at. However, as stated, I am willing to learn.

Thanks. A new or refurbished alternator is not expensive and not all that difficult to install. So, it can't hurt to replace it.