Zed Head

I fabbed up a crude snubber for the front of my R-200 differential, since I knew that the diff mount was showing signs of end-of-life (visible debonding when pried on with a screwdriver off the car), and found that it eliminated a bad clutch chatter problem that I was having. I assume that the weakening original rubber diff mount was allowing the front of the diff to bounce up and down at low acceleration levels, causing the clutch to stick and slip, ie chatter. Just putting this out there for anyone that may be having a clutch chatter problem. Something to look at. My clutch and pressure plate are brand-new, properly installed and broken in, but still chattered if I tried to leave a light or stop sign slowly. The snubber I made is fairly solid and positions a urethane bump stop about 1/16 inch above the diff at rest. In action, the diff rises up and contacts it, stopping the bouncing (my guess, not actually seen in action). The R/T mount or similar would probably have the same effect.

It's not clear if you meant fuel was flowing in your fuel lines, or you just saw that lines were full of gas. Residual pressure remains in the lines after they get pressurized, so the fuel pump may not actually have been energized. Maybe you know this but you could pull the wire to the starter and listen for the fuel pump when you turn the key to Start. It's the small wire with the female connector made to be pulled off and pushed on easily. The electric fuel pumps can usually be heard from inside the car. Pull the wire (make sure it's not touching a ground), turn the key to start, listen for the pump.

Shiny. Does it run right yet?

I don't think that a longer rod gives you more throw. Piston movement determines throw. A longer rod might actually use up some throw by preloading or setting a short starting position for the slave cylinder piston. Might be that you just need to bleed the system, with the original rod, adjusted to the proper amount of play. Air bubbles in the system would use up throw (piston travel) and cause your symptoms. I think the clutch is very easy to bleed, compared to the brakes. Just some thoughts, as to how I understand the hydraulic clutch system. Anyway, good luck.

If you could watch the clutch fork while you press the pedal (a mirror beside the car maybe?), or have someone watch it, or film it, or put an indicator on it - then you could isolate the the hydraulic side of the clutch system from the mechanical side (inside the bell housing). Then you would know if it's the clutch disc or pressure plate vs. the master or slave cylinders. More - if the fork moves but it doesn't release, it's pressure plate or disc. If it doesn't move, cylinders or pedal mechanism More #2 - or you might be able to get under the car, lever the clutch fork with a wrench or some pliers and see if it disengages. A wheel or two would need to be off the ground and the car in gear, while you moved the clutch fork and turned the drive shaft at the same time. Yoga.

I did not that realize the 68.7 reading you were worried about was through the fuel pump and the air regulator. There should be resistance there, the air regulator is a heater and the fuel pump is a motor. If the air regulator was bad, it would just affect your idle, either too low when cold or too high when warm. It bypasses the throttle, designed to raise the idle at cold startup. Your car runs so the fuel pump is probably fine. The Deoxit cans have an adjustment on the top. Low, Medium and High. I think they are set on High as-bought. I think that your main problem is in the AFM. As the FSM says, the values should be close to 180 and 100. 226 and 126 is quite a bit off. The ECU determines part-throttle injector open duration based on the AFM signal. Page EF-12 has a pretty good diagram of the AFM innards. EF-51 has a picture of the bottom of the AFM, with the connection point, and more thorough testing that you can do if you remove it.

It looks like someone may have already been inside the AFM, I don't think that they came sealed with red sealer. But I could be wrong. But it would not affect your bad resistance readings anyway. The black wire is a ground wire. The best way to clean it would be to take it out. Loosen up all of the hose clamps and hoses. Take out the three big Phillips head screws that hold the metal frame the AFM is mounted on. That's the bottom of the mount you're looking at in the second picture. Work off one of the hoses, I think the front one is easiest, and lift that end of the AFM up clear of the hose. Work it out of the other hose, but not too far, you will need to reach under it and get the wires clear of the mount point on the car. Then you should have room to turn it and see the connector, and be able to disconnect it. I think the connector is a little difficult to get off, it may have a wire clip or something holding it. It's been a while. The black wire you saw connects the AFM to the frame so will come with the assembly. The black cover just comes straight off of the AFM. There's really not much holding it on except the sealer. You might need to cut the sealer with a blade and carefully pry the cover off. Inside you'll see the black contact pad and the sliding contacts and the weight and spring. Rotate the weight or move the valve inside the air path and you'll see how the potentiometer works. No one is talking probably because if yours was working correctly, this would be "Not a good idea." But since you'll have to take it out anyway if you have it replaced, you might as well go for it. Have fun. It is a strange device.

Well, now you have the experienced guys on the case. Call the guy in CA. I would like to know if these are fixable without a rebuild too. If the core charge hadn't been so big I might have kept my old one to dink around with (maybe MSA knows that). They seem simple in concept. To be clear, the MSA rebuilts cost $169 and MSA did not give me any problems returning the core charge. As long as the aluminum body is not cracked or broken, the charge will be returned. But it is a risk, with a lot of money. To add to sblake01's suggestion, if you try the Deoxit, make sure you let it dry out before testing it. I tried something similar and tested it while still moist after and the numbers were all over the place. That contact area is really sensitive. After it dried though, they went back to the start values (the bad ones:cry:). But you might have some luck, it's worth a shot. Since you are working at the ECU connector, you should probably clean the connector at the AFM too. And that 68.7 reading could be a corroded connector too. Good luck.

Those are almost the exact numbers I had on my bad AFM. I had 227 and 126. The car would idle well, but popped and surged when you tried to drive it at part throttle. If you hit the gas though, it ran fine. Of course, I couldn't drive around at full throttle all the time, in my neighborhood anyway, so I replaced it. I got a rebuilt one from MSA (thezstore.com) and the car ran great after that. Until an injector died, but that took a while and is another story. MSA will either rebuild yours after you send it in, or send you one off the shelf if they have it, but with a $400 core charge. Apparently they are running out of cores to rebuild because people don't send the bad ones in, hence the huge core charge. Someone out there might have a used one if you want to save some money.

Hey Jennys280Z, here's a wordy response. I don't know why you don't have #13 - 16 parts. But I do know what they are suppose to do. They control the vacuum advance on the manual transmission 1976 motor. For whatever reason (probably emissions control vs. performance), the 1976 models had an electrical switch on the transmission that puts power to Part #13 to shut off the vacuum advance at all times, unless the transmission is in 4th gear. In other words, if you had those parts and they worked correctly, you would see vacuum advance only while driving in 4th gear. You may have figured this out already from the FSM. It took me a while though, but I did actually confirm it on my running engine (which has all of those parts and is non-CA MT). It looks like your car is set up to run full-time vacuum advance. I changed my transmission to one without the switch so that is how I run now. I think that it runs a little better. I have bumped my timing up a few degrees off initial also, just tuning for smooth-running. Do you have parts 33-36? If not, maybe your car was originally a non-CA automatic and got converted. If this is the case, you may have a different distributor also, EE-27, with a different vacuum advance canister. Love how every model year has something a little different.

ChrisA, thanks for the pictures and the write-up. I didn't realize, from the FSM diagrams, that the clips were on the inside until I saw your post, with the annotations. The FSM drawing has them shown on the outside, like a typical American manufacturer's placement. I would add, in my case anyway, that using a torch to heat up the metal around the bearing cups can make the difference in getting them out. I'm pretty sure that mine were the originals, and they would not budge, even with a 3 lb mallet, until I heated them up. Also, for those wondering if loose u-joints could be part of the "clunk", my car went from a significant semi-metallic clunk (a little bit clanky), to a more quiet "thunk" after replacing the four half-shaft u-joints (it sounds more normal now, considering how the suspension is designed). They made a big difference, even though only one bearing cup was dry, and the others were all mostly tight, they barely wiggled at all. The dry one was the only one loose enough that I would have considered it bad, otherwise. Thanks again, that was good information.

You can get a big 5 oz. can (much bigger than the tiny Radio Shack package) of Deoxit at Guitar Center, if there is one in your neighborhood, for ~ $15. It is the only canned sprayable liquid I've ever used that actually seems like magic. Quite often you can just spray it in to a corroded connection or switch and let it do its thing, without taking things completely apart. Very useful when working with old plastic. Edit - Re the ECU plug - You have to pull some of the wiring harness down with the top of the plug to pivot at the bottom until the hook-like shape at the bottom of the plug clears the metal pin it is hooked on. It pivots down quite a ways before it comes free. It will feel like you're pulling too much harness out of the dash but that's how you work it out. On a 76 and 78 anyway.

I had the same problem with the Air Regulator (what Nissan calls it) on my 76. I pulled the guts out just like you did while trying to get my engine running correctly. Then broke one of the bolts n the manifold when removing it. I spent a lot of time at the oven and freezer figuring out that it didn't work right anyway. Not to be contrary, but actually I think that if you are going to remove it, you need to block the air hoses off, not connect them. Otherwise the high idle never goes away. The regulator is open when cold, allowing extra air past the throttle body to give the high idle. It completely closes when warm, it actually has a small 12v heater and bimetallic strip inside, to warm it up and close it before the motor warms up. It's described on page EF-17 in the 77 manual. From an engineering perspective, I think it's true purpose is to get extra air in to burn off the extra fuel from the cold start valve, the start enrichment and the after start enrichment from the ECU. It does the same thing as holding the throttle open a little bit. It looks like primitive technology but they still used them in to the 90s.

The other temp sensor is in the Air Flow Meter (AFM), called the air temperature sensor. The pins to check are described in one section of the FSM, page EF-22, and the values that they should read by temperature are in a chart on other pages, pages EF-53 and-54, along with the water temp sensor values. I don't know why they didn't just describe measuring the resistance at the ECU plug, it would make more sense, since it takes all of the connections and the sensor itself in to consideration. I have checked mine at only two different temperatures, a fall day and a winter day, and they read correctly so I have assumed that they were good. My car runs great, all sensors appear to work correctly, but I only get 16.5 mpg, mixed highway and short drives. I have the cold start valve fuel supply blocked, with a pressure gauge in its place, so I know it's not leaking (it was before). I haven't dug in to the tuning yet, plug reading etc., it's been too cold (which may be part of the low mpg). The AFM resistance can be checked at the ECU plug also, page EF-52. Described for the AFM removed, but the pin numbers at the ECU are the same as on the AFM itself. If anyone knows of a magic mileage improver, I would love to hear about. My two ton 95 Pathfinder gets better mileage. What brand of injectors did you get (question to jthill3)? I replaced mine with new BWD injectors. I have wondered if they flow the same volumes as the stock ones.

In looking back at this post, I realized how hard it is to understand. Here is a simplified rewrite, from memory (so please confirm wire colors and check power before cutting or splicing anything). If you use the atlanticz.com alternator upgrade procedure on the 1976 280Z you will need to cut the yellow wire that goes to the brake warning lamp check relay under the passenger seat and resplice it in to a wire that is hot only when the engine is running. If you don’t the relay will be connected directly to the battery when you are done, therefore will not work correctly, and it will also slowly drain your battery. The brake warning lamp check relay is only supposed to have power when the engine is running. You can tell if you have this problem if you hear relays clicking when you reconnect your battery. The closest and easiest power source is to the fuel pump power line, which conveniently has a junction at the connector that runs next to the rocker panel also under the passenger seat. It is shown on page BE-7 Detail A in the FSM. I cut the wire to the relay, crimped on a flat male blade connector and inserted it in next to the GL wire in the connector. The fuel pump is only powered when the engine is running (unless you have wired it direct). I also put a 10 amp fuse inline so I wouldn’t fry any extra wiring if the relay shorted out (there were high water marks under the seat from previous ownership). Don’t forget to insulate the end of the yellow wire since it will still be connected to the battery. Or you can dig in to the wiring harness in the engine bay, find the splice and cover it up there. I think it is spliced in to one of the red and white wires. In the short term, if you just cut the wire to the relay but don’t repower it, the car will run (assuming it did before you started), and the battery will not discharge, but the brake warning light in the speedometer won’t show that your parking brake is on and it won’t show when you have a brake system pressure imbalance. I hooked mine back up to avoid that smokey burning smell, plus it will tell me when the next wheel cylinder leaks out. If you have a California car, you might find a similar problem with an EGR cut solenoid(?), from what I can figure out from the wiring diagram. If you use the zcarcreations.com procedure, the battery will not drain but the brake lamp in the speedometer will not go on when the ignition is turned on before starting the car like it is supposed to, to show that the lamp is working. I hope this makes more sense.

Well, it looks like you were exactly right. I resisted my normal urge to try many fixes at one time, and focused on that one area. Let water run down the chrome trim covered drip rail above the drivers door, and after about a minute I saw the water running down the top of the rocker panel and puddling on the floor. I had the carpet and padding pulled up and the door sill piece removed so I could see when it started and where it came from. In my case the water was actually running under the rubber piece as it had pulled up from aging and cracking. The water then ran down the door seal to the seam where the door seal ends butt together, across the seam to the inside, down to the top of the rocker, then down to the floor. I ran a bead of GE Silicone II under the rubber piece at the front of the door and also caulked up the door seal seam. Let it cure for a day, waited for rain but didn’t get any, so I went ahead and hosed the whole car down (fully prepared to find the next leak in line) and everything stayed dry. Thanks for the help. By the way, the car is actually very solid. I think that is just surface rust at the seam. But thanks for the advice.

Thanks for looking. I had noticed that that rubber strip was pretty chewed up, it's at the bottom of the second picture, kind of green and with big cracks in it. I assume that's the one you mean. It actually has moss growing on it (pretty common up here). It looks like an engineering afterthought to keep sideways spray out, so I had overlooked it. But it does look like it's not fitting the way it was designed to. I'll build it up and try to make it look like the other side and see what happens next time I roll it out in the rain, or pour some water on it if it's dry out. It's going up on blocks tonight for a five speed swap so I won't know for a few days (barring unexpected problems). I'll get back with the results then. Thanks again.

It's been raining here in Portland and since I have my car out of the garage and running well, I have found a large amount of water on the driver's side floor. I've looked through the various posts recently and in the past and was able to fix my leaky hatch using that information, but I have not seen a similar description of what I have recently found. I tore up the carpet and find that the water seems to be coming down the top of the rocker panel where the plastic trim meets the carpet and running over the edge in to the car. There is a large hole under the drivers seat, I assume from the PO parking nose up in the past and having the water run backward. I park nose down and the water is running off the rocker panel forward. I assume the water is coming down the front door jamb but I'm not sure how it gets there. Has anyone encountered this type of leak? I have also noticed what looks like a rusty separated seam behind the front of the door also. Could this be the entry point? Here are some pictures. Thanks for any help.

Windshield wiper switch on intermittent?

Thanks very much. The Courtesy Nissan link seems to tell the story. Red is 0.3. Red is the new brown at Courtesy Nissan. I wonder why they did that. But atlanticz still shows red at 0.69. So there is some dangerous information out there. If your red is not a Courtesy Nissan red you could have some burnt components. Or if you have a Courtesy Nissan 0.3 instead of red 0.69 you could have some mysterious fusible link burnouts. Thanks again.

Well, maybe that's how the red/brown confusion started. Nissan is giving out new red for old brown. Was there wire size information with the links? I have seen information on the web that shows the red links as being bigger than 0.3 mm^2. The atlanticz page for instance (although their diagram shows orange for the 76) - http://www.atlanticz.ca/zclub/techtips/fusiblelinks/index.html . The red seems designed for a much bigger load than the brown, based on wire size alone. If so, the red won't give the protection the brown was designed for. I will have to go down to Nissan and see what they have for links. Maybe they'll let me measure some wires. Thanks for the reply and the work on the schematic. It would make a cool poster for a garage or den.

Hello. I'm new here but I really could have used this two weeks ago. It looks fantastic, and I second the comment about eye strain. Mine are still sore from trying to figure out how the mechanical voltage regulator was wired. The color coding is great, and you've gone better than the FSM also by adding color to the fusible links. But I see that you show two red links under the two covers instead of two brown ones. The labeling on the side of my 76 fusible link holders definitely says B, G, and two Br, and the manual says that B, G and Br are used also (page BE-6). I've seen some discussion around the internet that maybe the brown is really red and you should just use red ones, but my reading leads me to believe that the brown links are real, at 0.3 mm ^2 in size, just not used on many models and not as readily available as the other ones. Can anyone comment on this? And thanks again for the diagram and I'm glad I have the car it comes from. Bob

Thanks for the reply Dave. I made a hash of my first post though, (see edited). Realized that the job was only 80% done...

Made a mistake in my first post. Original and corrections shown below. Sorry for the messy post. Basically what I've found is that both of the two popular alternator conversion instructions will allow the alternator to charge, internally regulated, but they both leave loose ends for other components in the 1976 280Z. I am new to this site but thought I would share something I found out about upgrading to a 1979 ZX alternator on a 1976 280Z. Using the atlanticz.com instructions - http://www.atlanticz.ca/zclub/techtips/alternatorswap/index.html - the brake warning lamp check relay will be "hot" all the time, even with the key off, since it is spliced off of the S line to the alternator plug. I found that the slight amount of current it draws would drain my battery after a few days. According to the FSM, California cars also have an EGR cut solenoid that would also be always energized. I assume that the old mechanical voltage regulator ran the S line and/or brake check relay through the ignition circuit (I did not dig in to confirm) so this was not a problem. You can tell if you have a similar problem after the conversion, if you hear relays clicking when you reconnect the battery, with the key off. Edit 11:41 am 11/12/09 - The following is wrong, it will not let the relay work correctly. The relay needs to be energized when the motor is running/cranking, but dead when the ignition circuit is on. {{{I fixed the problem by wiring the system like zcarcreations recommends - http://www.zcarcreations.com/howto/voltreg.htm - to get the relay back on to an ignition circuit}}} I ended up splicing the brake warning lamp check relay yellow wire, which energizes the relay solenoid, to the fuel pump circuit, which has a plug in the vicinity under the passenger seat. The fuel pump only runs when the motor is running. Edit 11:41 am 11/12/09 - This part still seems right {{{, but cut the S line splice off of the circuit and wired it direct to battery + terminal.} This also lets the alternator see mostly battery charge and not the voltage after the loads on the ignition circuit. I get a smooth 14.5 volts with the S line wired direct, but was getting a jumpy over 15 for the short time I had it wired through the the ignition circuit (measured with a good voltmeter at the battery).}}} That's all I have. I enjoy the discussions and hope this helps someone out if they decide to go with an internally regulated alternator. p.s. I also found that the dash voltmeter is pretty easy to adjust using the slotted adjuster on the back of the gauge.