1977 280Z Fuel Pump Problems? Kind of a longish story.

[azuka]

I got my project car about a year ago. 1977 280Z with 39,000 miles on it. The original owner died in 2001 and her husband had no interest in his wife's car and stuck it in a pole barn until he had to move it. I ended up with it. Nice body needing modest help. But of course it hadn't been run in about 11 years. My backyard mechanic friends did lots of work and got it running. I did some more work and finally got it running very nicely, but when I had some exhaust work done, the guy pointed out that the body rails were looking kinda bad.

I bought replacement floor pans and rails and hired a local welder with experience in this kind of thing to install.

OK. When I picked up the car he told me that the fuel line had sprung a leak and he had repaired it, but then it sprang another leak and he decided that he probably should not be the one to fix it. So, I drive from his shop to my mechanic who is four blocks away and he tells me he will check out the fuel system.

Well, a week later I drop by and the car is still sitting outside, but now with a flat tire. He tells me he is going to bring it in the bay that afternoon. I drive by the next day and it is still sitting outside with the flat. My mechanic has disappeared. Shop is closed and apparently abandoned. Nobody answers the phone. AFter another week of this I decide I can't leave my car appearing abandoned and unloved for local kids to start screwing with, so I drop by to start the car up and drive it home.

By this time, the battery is dead. I had jury rigged a sensor bipass so the car wouldn't idle really high. Had worked like a charm, but unfortunately, I used a circuit that is always on, instead of one that is only on when the ignition key is in on position. So if the car isn't started regularly, the battery gets drained. Between my welder and my mechanic, the battery is so dead that it won't start even with a jump.

I remove the battery and charge it up at home and bring it back the next day. This time I was able to start the car while jumping it and drove it 4 miles to my home so I can figure out what to do about the leaking gas line.

I am now unable to start the car, even with jumping.

Now, when I had dropped off the car at the welder's, it had almost no gas in it. He told me he had added some because he 'might have' run it dry. Well, with all this going on, I'm trying to figure out if I have a bad fuel pump, bad fuel pump relay, or whether the fuel pump is just empty and needs to crank for awhile to get gas in it so that I'll get gas delivered to the engine.

How can I tell if the relay is good, or for that matter, if the fuel pump is working? Any other thoughts or advice?

I'm not sure I want to tow the car to my mechanic, even though he has finally showed up at the shop again. He hasn't returned any of my polite calls yet.

I also don't want to leave the car outside by the road all winter.

[Captain Obvious]

The 77 does not have a separate fuel pump relay. Only the 78's have one of those.

On the 75-77, the fuel pump is controlled by one side of the EFI Relay which is located above the driver's left knee. There are two relays in that one box, and one side powers the fuel pump. I think they might refer to that side of the EFI relay is referred to as the fuel pump relay in the EFI section of the manual, but the point is, you will not find a "fuel pump relay" in the car.

As for testing it and the fuel pump... Easiest thing I've seen is to pull the small spade lug connector off the starter and then then the key to "START". The starter won't spin because of the wire you pulled off the starter, but the fuel pump should run and you should be able to hear it.

[ZCurves]

My advice is to STOP everything and make a list of all of the Subsystems where the car needs attention. Download the Factory Service Manual (FSM), Fuel Injection Bible, and the '77 Color Wiring Diagram (Search this forum and you will find links). Next, prioritize your list with getting the car running - not even well, just stable. This way you can move it around and get it to places that can correct the items that are lower on your list like welding, paint & body, etc. The next thing on your list would be making the car safe - solve fuel leaks and make sure the brakes work -and work well. Get rid of wonky tires (worry about rims later). Do Not get in a hurry! The old adage - "Haste makes waste" is definitely true with ZCars. So I encourage you to take your time and do each of the Subsystems well - to factory specs (see FSM). It is frustrating and inefficient to be working all over the car at the same time.

So back to your original question - Fuel Pump Problems? Once you have downloaded the documents I mentioned above, look at each component of the fuel system. Check Fuses. Check Fuel Pump output. Change all filters. Is the fuel tank full of rust and crap?? One thing you could immediately do is to buy 3 or 4 Clear Plastic 3/8" fuel filters and place one between the tank and the fuel pump (You WILL need the others until you make sure your tank is clean - which it isnt). While you are at it, drop the fuel pump and check the tiny inlet screen for debris. The Clear filters will allow you to keep the balance of the fuel system clean as you inspect and rework each component. The work is not difficult, and this forum will provide you with all answers to your problems - because I assure you that someone on this forum has already encountered and solved whatever problem you are working on.

One last piece of advice: Put your Model Year, VIN and Location in your signature, this way other members can help you much quicker. Use the Search feature first, then post your question if you can't find your answer!

Best of Luck.

Edited October 30, 2012 by ZCurves

[black gold man]

You are 70 miles from the Datsun Doctor if you need a shop.

[FastWoman]

I suspect your fuel pump is fine. However, before doing anything else, please FIX THE FUEL LEAK! I remember when a defective fuel filter leaked on a very nice '66 Mustang of mine and caught the engine on fire -- inside my garage! Luckily damage was minimal. You must respect gasoline, or it will burn up your car and possibly something else.

If you want to test your fuel pump, hot-wire it to the battery, monitor its pressure with a fuel pressure gauge between the fuel filter and injector rail (engine not running -- 36.3 psi, as I recall), and monitor its flow rate by connecting a long, clear vinyl hose to the return line of the fuel rail and pouring the return into the gas tank's filler neck. Look for air bubbles (should be none), and watch for a slowing return rate as the pump warms up.

But please, fix the leak first!

[azuka]

Just a quick update. Not much to tell. I put 5 gallons of gas in the tank thinking that would be enough to prime the pump. Before all my welding and fuel leak issues, the car had been running great. So it is suspicious to me that suddenly the relay or pump don't work, when they were working fine before.

So anyway, I tried to start the car. It turns over just fine, but has not even come close to catching. I checked the fuel filter and it looks like nothing has been going through it.

Tonight, I'm looking at my 280Z Fuel Injection Manual. On page 3 they make a big point that you should be careful to NEVER let the Datsun run out of gas, as priming the pump can be very difficult and may require that the tank be completely filled before the pump will begin to draw again.

So now I'm thinking that I may need to fetch a few more loads of gasoline to 'fill' the fuel tank. And then give it a shot at starting.

I'm fully cognizant of the fuel line leak and the dangers of a fire and will tread carefully.

[Zed Head]

Will it start using Starting Fluid? If not, the problem is probably spark-related. Squirt some through a vacuum fitting on the manifold.

You can listen to see if the pump is running by removing the yellow wire from the starter solenoid and turning the key to Start. You'll hear it. Then you won't have to wonder if the relay (at least part of it) and pump work or not.

[azuka]

Another update - I am very discouraged. I squirted some starter fluid into the boot that goes to the manifold. Turned on the starter expecting some measure of success. But I got nothing at all. Just the engine rolling over and no hint of catching. So it sounds like it's a spark issue I guess. I tried to get a look at the Fuel injection relay. It's located near my left knee as I'm sitting in the car. But damn, it is tucked in there and really hard to get at. How do you get that thing out so you can test it?

Perhaps there is a better way to check for spark. I'll nose around a bit.

[azuka]

A new day here. Well, I bought a spark test tool today. I checked it on my unsexy Dodge minivan to see what is supposed to happen when things are working. Nice little spark showing up..... the closer the tester gets to the spark plug, the better the spark.

So, my #1 son and I tested out the Datsun. The tool showed NO spark. So next, I pulled the wire from the coil and let the end sit close to the engine block. Still nothing! No spark!

So, I definately have a problem, but I'm closer to the answer!

I figure it is most likely a bad coil or a bad relay. I'd like to take the clearly working coil out of my '79 280ZX and put it in my '77 280Z as quick easy and cheap a diagnostic test. But I don't want to make something blow up.

Can you swap out the coil between the 280Z and 280ZX?

[Zed Head]

Coils don't go bad often, at least the old Nissan coils. But you can test the coil, on the car, pretty easily, along with the injector circuit and ECU circuit. First, though, check that you have 12 volts at both terminals of the coil with the key on. If not, you have a power supply problem.

To test the coil, attach one end of a wire (an alligator clip works well) to the negative terminal on the coil. Remove the main, center, wire from the distributor cap, leaving it attached to the coil, and position the electrode on the end close to the engine block or valve cover, close enough to spark and in a spot where you can see it. Turn the key on, then tap the other end of the wire from the negative terminal to ground. Each tap will charge the coil when it touches and discharge it when removed, creating a spark at the main wire. You don't have to hold it to ground, just a quick tap, you're just allowing electricity to flow though the coil for a microsecond. Every third tap should fire the injectors. You'll get spark, spark, spark/click, etc.

The coils should swap for short test but they have different specs. One uses a ballast resistor, the other doesn't.

[ZCurves]

Azuka, you could also test your Ignition Module. Two weeks ago, my Ignition Module on my '78 was overheating and cutting off while I was driving. It turned out that the module was full of media blast material from when I had the car stripped during paint. I replaced it with a new one anyway and got my spark back.

FYI: There is a new on ebay (item#180446449818) here:

http://www.ebay.com/itm/Nissan-240Z-280Z-710-Ignition-Control-Module-75-77-OEM-/180446449818?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a0372509a&vxp=mtr

$138

Another one here:

http://www.ebay.com/itm/IGNITION-MODULE-LX511-NISSAN-280Z-200SX-620-NEW-/360295998709?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A1977%7CModel%3A280Z&hash=item53e350a4f5&vxp=mtr

$134

[azuka]

Me again. Well, I traded ignition coils between the 77 and the 79. The 79 fired right up and runs with no trouble, so I'm pretty sure that the coil that had formerly been in the 79 and is now in my non-starting 77 is good.

I'd like to test the ignition module. Not sure yet where it is located or how to test. I figure it's time to look at the FSM again.

In the meantime, I have to jump the car every time I try to test something. What a headache. I'm not ready to have it towed yet. I'm really hoping to solve this without engaging the services of the pros.