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no fuel?


Guest livewire23

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Guest livewire23

after hours of painstakingly testing everything I could test, and remote cranking the engine a gazillion times (i hope i didnt damage the cylinders), I have come to the following conclusions about my stock 1977 280Z.

 

1. It is not running. confused2.gif

2.It is getting a spark.

3.Firing order is correct. (153624 I believe)

4.Fuel pump is working.

5.Fuel filter is not clogged.

6.Cold Start is getting signal.

7.Fuel Injectors are getting signal.

8.The AFM is heavy piece of crap.

9.I dont think the AFM is opening.

10.Idle bypass area in throttle body is not clogged.

11. The L28 EFI is a confusing system. :mad:

12. Valves are not stuck

13.Gas tank has at least 2 gallons in it.

14.The pump is definately pumping, because even after i purged the fuel filter, a few cranks later it was once again full.

 

The engine cranks, but will not start. Maybe there isn't enough gas? The back of the car is raised on jack stands, and the gauge reads almost exactly on the E. I think I can hear an occasional very soft pop in some cyinders if II listen real close, but im not really sure. Maybe the gas isn't the ignitable kind? bonk.gif

 

Any suggestions on starting this bad boy? Tommorow Im gonna check the AFM, make sure all wires are hooked up. Then Im gonna spray starter fluid into the AFM. And im gonna tighten down al the hoses, and see if the AFM opens up. After that, Im gonna go do my physics homework. malebitchslap.gif

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I had similar proplems with my '76 280. After replacing just about every part of the EFI system to no avail(tank, pump, etc.), I ended up putting a puting a carb on. I'll go back to fuel injection when I do the V8 swap (20 years from now)

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Guest livewire23

well, good news. After readjusting the firing sequence a couple more times (don't ask) and spraying a whole ton of starter fluid in the throttle body, it started. rockon.gif2thumbs.gif Oh Yea!!! and then the revs bounced up and down, and it died, about 2 secs later. so now I have to go see if i can find a new fuel pressure regualtor (just a guess) at the pick n pull. Is the regulator supposed to get vacuum when cranked? mine doesnt. Maybe I should try for new fuel injectors while im out there. heck, ill try and pick up the entire assembly off a 280ZX. fuel rail, injectors, pressure regulator... but first, im off to the gas station to get a tank of good gas. I got this sinking suspicion that the current gas in the tank just refuses to ignite.

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Guest livewire23
Originally posted by Neil:

I had similar proplems with my '76 280. After replacing just about every part of the EFI system to no avail(tank, pump, etc.), I ended up putting a puting a carb on. I'll go back to fuel injection when I do the V8 swap (20 years from now)

cry2.gif

 

more testing revealed the following:

1.The intake is suckin in air

2.the AFM is opening about 1mm, which looks about right.

3.The engine has compression on at least one cylinder.I'm going to test the rest now...

4.WD40 isnt flammable enough to start an engine.

 

lol, just kidding about #4

The only things left that I can think of... Maybe the intake manifold is blocked somewhere along the line? How can I tell if the injectors are actually firing into the cylinder? Even if they aren't firing, spraying starter fluid in the AFM and throttle body *should* start it right? (spark+compression+starter fluid=running engine?)

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Guest livewire23

bought it like this off philanthropy. its gonna be a swapper, so getting it running is just something to do in my spare time.

 

After spending the whole day with the car, tweaking this and adjusting that, I've decided that the fuel injectors must be completely gummed up. Its either getting no fuel at all, or its really lean. either way its gotta be the injectors, because they are recieving power, and there is plenty of pressure in the fuel rail. Im debating whether to go to pick n pull tommorow and attempt to get carbs, or to just let the engine sit until I get my donor car. I dont want to shell out the $30 or so per injector over at autozone, I've already spent too much on this engine (at least for this month).

 

On a happy note, the 280z has a real sweet exhaust note. nothing like an extra 2 cylinders to deepen an exhaust. ;)

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Guest livewire23

some guy i worked with says he used to work at a datsun dealership, and he thinks that without my CSV working, the car will never run. he says that the engine doesnt switch over to FI unless the cold start valve is working first. Can anyone confirm/deny this? I didnt get a fuel pressure gauge because, well because im cheap and i wanted to check this first.

 

-Kito

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csv is cold start valve right? you dont need that, its nice, but you dont need it, if its hooked up i wouldnt mess with it. man you run your zx with only injectors and it runs good? that sounds nuts, did you say you even had the afm unplugged and it still runs?

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Guest livewire23
Originally posted by LEN168:

did you say you even had the afm unplugged and it still runs?

whoa. that would be cool. I think he just has the AFR disconnected, not the AFM.

 

Well, that confirms what I thought, the 280 aint so advanced as to switch electronically from CSV to FI. oh well, looks like i gotta by a fuel pressure gauge. everyone at sears thinks im miserly because I spend an hour staring at every took trying to decide whether to buy it. The cashier was laughing at me when I was debating whether $1.50 - associate discount was too much to pay for air tool oil. twak.gif Eventually I bought it, but i put the wheel chocks back on the shelf. That's what bricks are for...

 

anyway, i guess its time to unplug everything. TPS, CSV, maybe even the thermotime switch. As long as it'll run alright cold, it should be all good. the less stuff attached, the better, at least for now. BTW, anyone have any good ideas for getting the injecors out? the screws that hold them on are all brittle and strip too easily. anyone tried those screw-out things?

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Air Flow Regulator. Its that thing that lets air bypass into the engine when it is cold so it maintains a higher idle until warm.

 

The CSV is only used for cold start ups and it works by injecting fuel into the air passage int he manifold, enrichening the mixture.

 

You really dont need any of that stuff.

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Guest livewire23

hmm, how do i set the timing with the engine off? By the way, the car is now firing on one cylinder. I replaced the fuel pressure regulator, and the fuel pressure went up a lot. so clearly the old one was busted. Now im firing on one cylinder, but unfortunately, thats not enough to run an engine. so... could it still be the timing?32

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Guest livewire23

well, its time for new fuel injectors. Is there any kind of upgrade I should make at this point, or should I just go for stock replacements? I eventually plan on going the turbo route, but not yet...

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Ok heres what you have to do to get the timing close...

 

1. Get #1 cylinder up to TDC on the compression stroke. To do this take out the #1 plug, put your finger over the spark plug hole and have someone crank the engine(by the way disable the fuel pump and ignition sytem), when you feel the pressure start to build wait for it to peak out, now turn the motor with breaker bar and socket till it is exactly at TDC (stick a screw driver in the cylinder to check this)

 

2. Now that it is at TDC look in the manual to see were the distributor should point when the #1 is at TDC.

 

3. Set the distributor in and tighten it up so that it doesnt move when you try to start it but loose enough so that you can still turn it by hand.

 

4. Now set the timing with a timing light.

 

Let me know if you need more help with that!

 

Guy

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Guest livewire23

it runs! 2thumbs.gif i cleaned the injectors with some alchohol, and it came to life. right now its running on 2 cyylinders, but thats just because the plugs keep fouling. Its running ultra-rich, but hey, its better than not at all right?

too bad i cant get it running smoothly enough to take to the gas station. It needs it desperately. ugg.gif Thanks for the help everyone, especially don for helpin me get it out here.

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Hey livewire have you checked your timing or location of the distibutor?

 

Cause lets say your 180 degrees off on the timing...that would make your plugs fire when your on the exhaust stroke not on the power stroke. The injectors would still fire on the intake stroke but all that gas would just go out on the exhaust stroke when there is no compression. You kinda get what I'm saying? Before you go out and buy parts, I would check your distriutor location and set the timing as close as you can with out the car running. You HAVE to close to base timing for that engine to run!

 

Let me know if you need some help with that!

 

Guy

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  • 2 months later...
Guest cw280z

when i first got 81 coupe it had sat for 3 years i could not get it started ....

had spark,replaced injectors,air regulator,etc etc.....

turnd out to be the block temp sensor.

as soon as i buy a new one and get it in there i found out about using a potentiometer to by-pass it all together and have a dash controled unit.

i'm asuming the 79 efi had one?! :)

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Before you bring out the shotgun, and go for new injectors, please check your ignition timing once more. You might have the sequence right, but you could be 180 degrees out. I've done it myself - aligned #1 terminal on the cap with the rotor at #1 TDC, but it was the wrong #1 TDC (exhaust stroke, not compression stroke).

 

And I also say this because I've NEVER seen all 6 injectors go so far gone as to not fire at all.

 

If your ignition truly is correct, checks out fine, then pull off the fuel rail without disconnecting the hoses, and crank that to see if you get spray out of the injectors (keep a fire extinguisher handy :))

 

Good luck.

 

Edit -- OOPS, posted before I read the second page, my bad...

 

And the temp sensor is a good suggestion - if it falls off, the car will not run AT ALL. A guy I know running at the track had that happen, we were scratching our heads, and said, what's that wire hanging off? Hehe.

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