77 280Z Stored for 10 Years and Running when garaged

[azuka]

I bought this car on a whim last fall from 'the original owner.' Well, that's not exactly accurate. The original owner died unexpectedly in 2001 and her husband just wasn't into driving his wife's baby so he stored it in a pole barn. Ten years later, he had to sell his home, etc. and had to unload this car. I'd wanted an early Z car for many years, but could never justify it. So I bought this one, towed it home and with the help of a backyard mechanic got it in running condition.... sort of.

The seller said the car had never been driven in winters and was mostly a weekend trip kind of car. Said that the 39,500 miles on the odometer was accurate, and NOT 139,500. I have no way of verifying this of course. Looking at condition of rubber pads covering the brake, gas, and clutch pedals, it doesn't look like they have extensive wear, and looks about right for the mileage on the car.

I'm no mechanic, but my friend is not going to be doing any more work on my cars. Either I'll do the work or I'll have a real mechanic do it. At any rate, the car isn't quite right yet. Biggest problem is that the idle will drop to nothing and stall out at stop signs and lights etc. I suspect the culprit to be varnish deposits caused by my idiot friends who did NOT listen to me when I said all fluids must be drained before running the engine.

Right now, April 14, 2013, the car is driveable if you can tolerate the idling issue (I can't!) The brake light is on too now and I'm pretty sure I've located the leak, another present from my backyard mechanic. I took it to my local real mechanic yesterday to address that issue as well as the idle problem.

I suspect the idling issue can be cured once I've driven it enough while letting seafoam do it's work. I've only put 60 miles on its first full tank of gas since putting in the seafoam. Looks like the idling has improved. Keep in mind that early on, I adjusted the idle as high as I could to counteract the low idle problem, it didn't really help the problem, but when it idles it idles around 2000 RPMs. Now that I've driven it for awhile with seafoam in the tank it will now idle at 2K RPM 50 - 70% of the time, and when it doesn't do that, it will start to idle low on its path to a stallout. But if I tap the gas pedal, this seems to fix that and then it idles high. My take is that the idling problem is almost fixed and I just need to drive the thing on a long trip or two and to adjust the idle down to a normal level. Otherwise, the engine sure seems to be in nice smooth running condition.

The radio antenna worked perfectly a week ago, but now will not project up when I flip the antenna switch.

I'm not really asking for help here, just thought I'd post my story about this car. Of course, if anyone has some special insight or advice, I'm all ears.

Steve

[72 OJ]

It is great for mental health to tinker with old Datsuns.............

Edited April 14, 2012 by 72 OJ

[zbane]

What have you already done to the car in order to get it back on the road? I would assume you've changed all the filters, checked vacuum lines, fuel lines, etc...

Have you peeked into the gas tank to check for rust and sediment?

[Zed Head]

You might have a vacuum leak. When you open the idle screw you're letting more air past the AFM which will add more gas. This counteracts the lean mix that the vacuum leak causes. But all of the extra air leads to a high idle. Does the idle change when you press on the brake pedal? That would be a bad booster, which causes a vacuum leak when the pedal is pressed.

The crankcase (this includes the valve cover and all hoses) needs to be completely sealed for the EFI to work right. The oil filler cap, dip stick tube, breather hose from the top of the valve cover, etc. all need to be sealed.

[Wade Nelson]

Will it idle if you sit there and continually spritz (starter fluid, brake cleaner, anything flammable..) into the intake while it is set to idle at 800 rpm? If so....

The idle circuit in your carb(s) is plugged up. No amount of Seafom or carb cleaner (poured in the gas tank) is gonna cure it. Once there's a plug of crud in a microscopic hole in a casting, nothing flows past it or is gonna dissolve it.

Yes, you SHOULD have drained all the old fuel, that MIGHT have prevented the passageway(s) from getting blocked. Next time listen to your OWN common sense, take the difficult path, not the one that appears to be easy.

The cure is taking the carbs apart and rebuilding them, including getting the idle circuit(s) open using either compressed air or a wire off a wire brush.

Find an ole-timey carburetor guy. Do NOT let your young (under 50 these days) mechanic who has ONLY worked on fuel injected vehicles attempt a carburetor rebuild. Ask around at a couple of shops --- "Who around here used to rebuild carburetors?" Even if all they worked on was 4bbl Holleys and Rochesters, the knowledge/experience is similar enough. Someone who has worked extensively on lawnmower or motorcycle carburetors will also have sufficient experience to guide you through the process.

You'll need to find / order some carburetor "kits." And no, you do NOT want to attempt this yourself if it's your first carb rebuild. You will be looking for small parts / springs on the floor for days, mis-assemble it, etc. Hint: working over a clean white towel is #1 when taking carbs apart, and do them one at a time so you REALIZE when you mis-assembled the first one.

If adding faux fuel will NOT allow it to idle, you have OTHER problems besides the idle circuits, like vacuum leaks, rotten hose to the distributor advance, sticking valves, etc.

Next time, whether it's front end work or HVAC plumbing, I suggest you seek advice BEFORE starting the process, not once it has gone awry. That is what the Zen student would do.

[Wade Nelson]

280? Fuel injected? Skip the carburetor advice, replace the fuel filter then check the fuel pressure after replacing all the 3/8" fuel injection hoses in the engine bay which are now filling the injectors with rubber bits, be sure and get FUEL INJECTION clamps, not screw-type hose clamps, and figure you've got a 50% chance of needing new injectors. Listen to them with a stethoscope.

[Wade Nelson]

Sorry I can't get my !@#$@# together and give you a single, worthwhile reply. Assuming it's fuel injected, find and fix the leaks /cracks in ALL the hoses from the mass airflow sensor to the manifold. It must be 100% sealed or "false air" which was NOT measured by the MAF will cause it to run lean and stall out. Take the bellows-type hoses off, wash and inspect OFF the vehicle.

[Walter Moore]

Good luck.

If the car runs that is a good place to start. You might consider taking it to a good mechanic in your area to give it a quick once over, particularly if you are not good at working on cars. Otherwise you will either have to learn fast, or will end up giving up.

[Willoughby Z]

Sorry I can't get my !@#$@# together and give you a single, worthwhile reply. Assuming it's fuel injected, find and fix the leaks /cracks in ALL the hoses from the mass airflow sensor to the manifold. It must be 100% sealed or "false air" which was NOT measured by the MAF will cause it to run lean and stall out. Take the bellows-type hoses off, wash and inspect OFF the vehicle.

77 280 has EFI. And there is no MAF- it has a Air Flow Meter (AFM).

[justinyee]

Hey Azuka - ever get the issue figured out? I've have the same car with the same issue, so I know exactly what you're going through (and still going through!). I've tried the oil, fuel filter, spark plugs, seafoam in oil, AFM boots, higher octane, and listening to high and low whine of the fuel pump. Next up for me is to try (after reading this thread) is to check air leaks, seafoam in gas tank, fuel pump, AFM unit. For a while though, the car behaved well during the summer, and didn't have any consistent issues come back until now.

I know there's a few threads on this symptom already (i've created / commented on a few of them myself). Just wanted to prompt others to follow up with their experiences.