78-280Z

Is this a drop-in for a 1978 Datsun 280Z? I am very interested. I believe the 78's come with the R200 3.54 Diff (long nose).

Zed, thanks for your insight. I really do appreciate having you to bounce ideas off of (moreso to correct me).. I am going to drive it around for a couple of more days to use up some of the fuel and make sure that this gas "fill-up" was indeed the "fix". This will give me assurance it's worth digging into the fuel tank. I think I will do as you said and drain out the tank and see what I find. I think I may just drain it instead of using the fuel pump so that way if I do have gunk in there, I avoid pushing anything more than I need to through any lines/pump unnecessarily.

I had the "Original" ignition coil. Or so I think. I switched to the Pertronix Flame-Thrower 3ohm for my 78 280Z. They say if you don't have the ballast resistor, to go with 3ohm. If you have it, go with the 1.5ohm ignition coil. The 78 does not have one. See below:

Hi Zed, As usual, you were right. I fixed a number of other issues that I had and it ran great for a day. Then yesterday when I was a little under half a tank, it started with this whole lean + backfiring in the intake issue. I went and got gas (topped it off, added like 9.5 gallons) and now she runs like a dream again. I do believe now the only thing that could be causing this, is something blocking the fuel outlet port. I assume the only way to deal with this is to drop the tank and clean it out. Any other "less time consuming" potential issues it could be? If not, I will probably get to the tank in the next couple of weeks. Fuel hose 3 here would have to be blocked? It does have a new fuel filter in the engine bay.

It turned out to be caused by my ignition coil. I replaced it and now the tach reads very steady across the board.

Zedd, I'll have to check the air gap tomorrow. It could be that. When I retard the timing on the distributor, the sound goes away. It must be there somewhere. Also, it seems I figured out what my problem is. When you unplug the harness for injector 1 and 2 when the car is running (but stumbly), nothing happens. When you disconnect another one, car dies. So this tells me injectors 1 and 2 aren't functioning. I did the tests from the Fuel bible. There is battery voltage going to the harness for each injector. Each injector has ~3-4ohms of resistance which I guess is normal for a low impedance injector. I can also hear them clicking when i supply 12V to each. This tells me electricals are all in order. I guess they must both be clogged? The reason I'm hesitant to believe it is because the PO gave me a receipt that he had them professionally cleaned 6 months ago. The car also runs great half of the time. Then all of a sudden it gets stumbly and that's when I pull the injector connector and nothing changes for 1 or 2. Is there any test I'm missing? I did check fuel pressure a few weeks back and it was within range ~32psi or something like that. I remember verifying at the time.

I found a ton of threads of similar issues as mine but no one ever posts back with their fix... http://www.classiczcars.com/forums/topic/30120-78-280z-rough-idle-when-hot/ http://forums.hybridz.org/topic/113290-77-280z-rough-idle-after-warm-up/ and so on...

PS - I was just trying to delete the second post with nothing in it. Also, I'm getting a buzzing from my engine bay and it sounds like it's coming from my distributor. My cap and rotor were replaced. I tried a search and didn't find anything. When you give it gas, it changes then goes away. See below for the video:

Hi Zed, Thanks for sticking through these problems with me. I was at work when I posted that. I knew that's what I'd do next but in case I missed something I wanted to be ready with things to try. I replaced the bullet connectors for the WTS and it helped. Sort of. The car now runs and idles great when it's cold and up to operating temps. It hauls and is a ton of fun to drive. Up until the temperature arrow is a little past halfway on the gauge then it starts to sputter at low rpms and at idle. In the higher rpms it gets a little power back but struggles. I pulled the plugs after a drive and they are nice and brown. Much better than the black plugs from yesterday. This confuses me because the only thing that could cause the engine to stumble would be something happening in the combustion chamber. If there is a good burn happening in the cylinder, why would it stumble like that? I do own the FSM and the fuel injectio bible. I've read through them and it's how I avoid posting all of the issues I have on here. Side note, maybe related, maybe not. I checked all the spark plug wire resistances because it's the only thing (aside from the ignition coil) that I haven't replaced. The previous owner gave me a receipt that they say they are new and were replaced 6 months ago. However do not have a brand name on them - looks like someone just made them to length. Resistances were read cold after sitting all night and are: 1 - 6.96k Ohms 2 - 9.40k Ohms 3 - 8.14k Ohms 4 - 8.65k Ohms 5 - 10.43k Ohms 6 - 8.27k Ohms The FSM says "Above 30k Ohms, replace". I also recall reading that they should be ~11k ohms but I can't find that page again. My question is, should these wires be replaced? Could they be a problem?

I didn't disconnect them so that can't be it. I'm really hoping I just pulled out one of those bullet connectors for the WTS that's right by the fuel rail.

Disregard. Can't figure out how to delete this post.

Hi all, Yesterday I replaced all of the fuel lines from the injectors to fuel rail. 2 of them were starting to leak. I replaced with the proper FI hose as well as clamps. After that, I started the engine up and it started and ran great. Once it warmed up, I noticed a pinhole leak in a short coolant line that was squirting a little coolant out (maybe I nicked it with a screwdriver). After that, I turned the car off, replaced the line and when I tried to start it up again - it would not. It would crank but not start. With a line on the carbon canister disconnected it would start though and idle very rough. I gave up for the night. This morning, I went to start it with everything hooked up and it started right up. However, it idles very rough - very rich it looks like by the smell and smoke. When I replaced the fuel injector hoses, I did not fully remove the fuel rail, just loosened it up everywhere and tilted it back. I had to remove the distributor cap to get access to the coolant line as well. After some research and based on the fact that it started cold this morning (probably 55F out this morning), could it be the water temperature sensor? Perhaps it thinks the engine is very very cold and it's supplying too much fuel? Can I jump the prongs on the Water Temperature Sensor (with a paperclip or something) and see if would stop supplying so much fuel? I'm weary of thinking it's the WTS only because why would it break all of a sudden? But perhaps I hit it when I was moving stuff around. I will check the resistance when I get home but would like to have some other ideas on what to check when I get there. NOTE: The engine is getting fuel, spark and air. Because of this, I think it's some electrical sensor issue. I verified all of them. I pulled the spade on the starter, turned the key and saw fuel coming out of the fuel supply line. I checked all spark by pulling the spark plug wires one by one while running. Spark would jump the gap and make it from the wire to the plug. See below for pics: This is the short coolant hose I replaced. Engine bay in case you see something I missed or re-connected incorrectly. The line I disconnected on the carbon canister and it ran the first day. AGAIN, this morning when it started no problem (but rough), this was connected and idled. What my car looks like... so you can feel my pain about how I can't drive it right now! And I just got new tires (old ones were dry rotted). I'm ready to enjoy the open road!

I believe the one that we are currently asking about is the Saturn Vue steering column assist. I am curious to see anyone who has pictures of this setup. It seems that if it was mounted in the engine bay instead of under the dash you wouldn't need to modify your steering column shaft. Some adapters would be needed in the engine bay though to make the unit fit.

Does your steering column shaft have to be cut around where your pedals are? How did you mate the electric unit to the shaft? Re-splined or just put some bolts through it? I'm very interested in doing this as well.

Would you mind sharing the info on your wheels/tire setup? What rim/offset/size?

Thanks for all your help and knowledge Zed. Now to deal with my seized fan clutch...

Zed, you're right. I did not disconnect the fpr. I can test again tomorrow but read on for my discovery today... I put the old plugs back in (for the heck of it) and tweaked the timing a bit. I then noticed it was a tad better and at this point i was down to maybe a couple of gallons of gas. I drove to get gas and it drove like crap on the way there. When I removed the cap, it hissed a lot. This told me there was a lot of vacuum in the tank. These cars don't have vented caps, where/how are they vented? I filled it up with 93 and it drove AMAZING on my way home. No stutter, full power. It has literally never felt this good. Do you think there was so much vacuum in the tank that the fuel pump was really struggling to get the fuel to the rail causing my lean condition on a tank low on fuel? PS - when i hooked up the fuel pressure gauge, I got no pressure with the key to the on position. Only once I started the car running did I get full pressure. This also makes me think fuel was struggling to get up the engine.

Fuel pressure is right around 32psi. The FSM calls for 36... Is 32 OK? Or do I need to replace my FPR? My fuel filter in the engine bay is new and it looks like my fuel pump is not original and does not have a little fuel filter on it like the OEM one. Even after I shut the car off it's staying up there, telling me it's holding the pressure.

This tip will probably make the engine run right, although the original problem might remain - http://www.atlanticz...rpot/index.html I will pick up a potentiometer on my way home today just in case I can't figure out the issue. My plan is to adjust valve lash too. The car supposedly sat for years before the PO bought it (he only had it for 6 months or so) and don't know its history before that. Who knows if it has ever been re-adjusted. Could bad valve lash cause this issue? A valve could not be closing all the way or staying open too long? Fuel pressure is critical. It needs to be known. A weak pump, or a clogged filter or tank can cause your problem. Vacuum leaks can also cause a lean condition. The intake system, including the crankcase (PCV) needs to be sealed from outside air. All air must pass through the AFM. I am renting one on the way home today to verify this before I try the potentiometer too. From what I remember, it should be around 35-38PSI most of the time? I sprayed over every line I could find with carb cleaner and my idle did not change so I do not think I have any notable leaks unless there is one hidden somewhere that I can't find. I replaced all but 1 or 2 vacuum lines on the engine a couple of days ago to eliminate any potential vacuum leaks. I also cleaned out the PCV valve (it's not sticky - I blew in it and made sure it only flowed in one direction). There is an inline fuel filter near the pump, correct? I have not checked it yet. Any info on removing it/cleaning it? I spent a lot of time tuning my car, then found that several of my injectors were clogged. The car sat for quite a while before I got it. Your AFM numbers look great. Don't mess with the AFM spring unless you're positive it's already been messed with. Numerous people have got lost inthe AFM internals and ended up buying new ones because they didn't know how to get back to where they started. Mark your starting point if you get in there. There should be a blob of glue on the set screws for the cog, use a bright light and magnifying glass to see if they've been broken. The side cover just pries straight off, no clips holding it in place. I don't plan on messing with the AFM. I've done enough research to know I should start elsewhere. All of the injectors were cleaned out before I got them. I have receipt from the PO saying he had a shop do it 6 months ago but I supposed it wouldn't hurt to do it again myself. The problem is very very common. I found many similar posts to mine but never did anyone post back with a solution if they ever figured it out!

Hi all, My car was stuttery when I bought it (2 weeks ago) and have not driven it much since. I have been trying to tune it up. Yesterday, I put in new plugs (the ones the FSM calls for), distributor cap, and rotor as well as a new fuel filter (the one in the engine bay).. All from MSA. After that, I used my timing light to adjust my timing. I verified TDC with the rotor pointed at spark plug 1, cylinder 1 was at TDC and mechanical timing was at 0. I then disconnected the vacuum advance at the distributor and capped it. I checked the timing and found it to be about ~15 advanced. FSM calls for 10 so I retarded it to 10. It idles happily at 10*. However, when I try to rev it, it's sometimes good, and other times it backfires in the intake (frontfires?). I had driven it around a bit after this and when I came back from my short drive (it front-fired a fair amount) I pulled a couple of plugs and they were pretty white. The front-fire in combination with the white plugs tells me that I am running lean. When I pulled the original plugs, they looked normal (light brown) I am trying to figure out why it is running lean. I tested the AFM and these were my results Resistance between 6 and 8 = 184ohms, normal Resistance between 9 and 8 = 103ohms, normal Continuity check of 6, 7, 8, and 9 are all 0, normal. I will run 12V to the AFM when I get home to check the potentiometer readings. There is some gray silicone around the plastic cover on my AFM - does this mean someone has messed with it before or is that how it was sealed from the factory? I have yet to open it. If this means it was altered, I may open it and try and set it back to original specs using this link: http://www.atlanticz.ca/zclub/techtips/afm/ IF I can figure out what the OEM specs were. I do not want to adjust the AFM to mask a problem. I do not want to alter it any other way since you're not supposed to. I'd just want it back to stock specifications. Resistance from 27 and 8 (air temp sensor) is inconsisten(ish). I will only get a reading when I tap the my multimeter probes to them and it will give me a reading for a quick second then disappear. I can't get it to hold a reading. When I see the blip of a reading it is between 1.5k ohms and 1.8k. It's probably around 75 degrees in here and 68 degrees would be a resistance of 2.25k - 2.75k. So if those readings are accurate, it may be a little off. What concerns me is it not holding a resistance. Could it be a bad temp sensor? Would it cause my car to run lean? I am not sure what the temp sensor defaults too when it fails. If it defaults to thinking the temperature is really hot, it could not be providing enough fuel. I know the ECU only adds extra fuel when the incoming air is below 70* F. I do not have a vacuum gage or a fuel pressure gage so I cannot verify those two things at the moment. Thoughts? What is the default mode of the AFM if I disconnect it? Would it run "rich"?

Unfortunately, I do not have an oscilloscope. I will see if I can track down that resistor today and measure the resistance at it. Thanks beermanpete!

I just replaced my speedometer (and I may have missed something) but there is a connector that is on the pigtail but I can't find anything to connect it to. What am I missing and what is it for? It's the connector on the top left of this picture that's just hanging out. Everything seems to work normally without it connected - speedo reads, high beam bulb and brake bulb both work as well so I am wondering what it's for.

In addition, I cleaned off the terminals, re-checked the gage connections and all seems fine... I can't figure out why the tach won't read below 1000. Any ideas?

I measured the frequency at the ignition coil yesterday across both terminals and got .46Khz = 460Hz. This number doesn't seem to make much sense using the formula above. Unless it was .046Khz... I'll have to check again when I get home. It was almost midnight when I was doing this last night. For those that see this later and dont understand the equation it's: Hz x 60 to go to per minute x 2 (assuming you're firing every other revolution), dividing by 6 (cylinders) which would give you the RPM. [Frequency (Hz) x 60 (sec) x 2 (Firing every other revolution)] / 6 (cylinders) yields the equation of: Hz x 20 = RPM (for a 6-cylinder 4-stroke engine)

Can you elaborate on what I would be measuring at the ignition coil? I'm not too bad at the math part although electrical things are not my strongsuit. That's a good idea, I imagine it doesn't start advancing timing until higher up in the rpm range. I plan on setting the timing tomorrow once my parts are installed and I have replaced all the vacuum lines. I don't want to adjust it to an inaccurate idle speed caused by a potential vacuum leak.