[ryanb80]

Ok guys.

Here is the run down, no starting. 1980 280zx

3 weeks ago I go to start the z after sitting in garage for 2 months, the battery was dead so I charged it up first.

It turned over, started and died immediately, try it again, same thing, would not run at all. Finally the battery went dead again.

Ok, here is what I have checked with the service manual.

- Cold start vavle and thermotime switch circuit and sensors, all tested normal.
- throttle switch circuit and sensor static checks - all good
- air regulator circuit.
- air temperature sensor static checks - all good.
- cylinder head temp sensor static check - good.
- electrical circuit checks from control box, static checks on resistances - all good except one - pin 26 read 4.4 ohms and should be between 40 and 70 ( which is the resistance of pin 45 I think to ground on the thermotime sensor ), yet I tested the same connection on another 1980 and it read the same 4.5 ohms and that car ran fine. It is also temperature sensitive so I do not think that is the problem,
All other elctrical static checks are good.
- checked ignition coil resistances and injection circuit test with grouding negative lead on coil and all injectors click normally, no breaks.
- checked and cleaned all above sensor contacts.
- Static resistance checks on fuel pump relay #2, efi relay
- Tried a loaner EFI control unit too from same year.
- replaced starter
- I am getting fuel but am not sure of pressure, I did the fuel pump test with the starter disconnected and fule pump runs and sounds normal, also.... fuel pressure regulator is new and sounds normal.
- Cold start valve is new
- 6 new injectors last year.
- Resistance from distributor cap to end of wires is withing specs
- Cap is not bad, some corotion, but only minimal ( I cleaned it up anyways ).

My thoughts - no time to test until the weekend.
1. no power to distributor or problem with distributor ( have not checked for hot spark on wires yet .
2. wet and foulled plugs - which would explain everything and be the simple solution, so that is probably it.

I originally thought it was a bad fuel pump, but I was told that those are rarely replaced so that is when I started into the book with all the static checks and lead me to the above conclusions so far.

( it is not firing up anymore, the starter is cranking the engine but absolutely no spark, so that made me think of bad plugs ).

The engine is not seized cuz I can crank the crank shaft by hand, it also ran perfectly fine before I parked it and the oil is full with regular color and smell.

HELP..... any ideas are welcome no matter what it is.

 

[Nicks 83zxt]

if you are not getting spark to the plugs and the injectors are not firing I would suspect the crank angle sensor. Why was the Fuel Pressure Regulator replaced? was it bad? If the FPR was faulty it will over work the pump and most times kill it.

That's all I can think of right now.

Nick

 

[ryanb80]

Could the crank angle sensor just stop working? where would this sensor be, I never saw it in my check list in the book.

I replaced the FPR because I got cost on a new one from Nissan, so I replaced the ugly, scratched and coroded one with a nice shinny new one. old one still works fine.

Ryan

 

[Randy Nix]

If you have no spark it will never start and the plugs should be wet after you try. Could be coil or control unit, or maybe air gap on distributor. See if you get fire from coil, if so it could be dist. cap or rotor or wires.

 

[ryanb80]

ok, lets say that I check it this weekend and I get spark from the distributor to the plugs? and it still won't go ( like it did at first, 3 weeks ago... )

Ryan

 

[Randy Nix]

You only need fuel, compression, and spark at the right time to run. Since the compression shouldn't have changed I would say that if you have spark you have no gas to plugs. The timing/distributor hasn't been turned has it?

 

[ryanb80]

timing and distributor have not been touched, other than pulling the cap to check the leads for corosion and check the resistance between the lead and the end of the wires.

So if I get spark I am going to try another fuel pump. I know the line is not blocked, then again it could be partially plugged...... the fuel rail is good and clean, i had it off last year when I replaced the injectors, I also chrome plated it to make it look nice.

how the **** do I check a fuel line for blockage?

 

[Randy Nix]

The fuel system is under a lot of pressure. Loosen the clamps where it hooks into the fuel filter up front and be careful, if the pump is working gas should spray out.

 

[ryanb80]

it doesn't spray out, so I think it may be the pump, it has pressure but not a lot.

It does spray a little, but not a lot.....

 

[79-280-ZX]

The following could be a typo on your part:

- electrical circuit checks from control box, static checks on resistances - all good except one - pin 26 read 4.4 ohms and should be between 40 and 70 ( which is the resistance of pin 45 I think to ground on the thermotime sensor ), yet I tested the same connection on another 1980 and it read the same 4.5 ohms and that car ran fine. It is also temperature sensitive so I do not think that is the problem,
All other elctrical static checks are good.

My book says Pin 26 is the Start Signal Circuit.

It should be battery voltage with the following conditions:

1: Starter solenoid lead disconnected
2: Cold start valve disconnected.
3. Key held in the "Start" position.

Other things to check:

Put a fuel pressure gauge between the fuel filter and the upper fuel rail. You should have at least 32 PSI while cranking the engine.

If the battery voltage drops below 9 volts, while cranking, the ECU will not function.

Did you put any fuel stabalizer in the tank before you stored it?

Have you got fresh fuel in it now?

Wayne Monteath
Masham, Quebec.

 

[82GoochZX]

Hello ryanb80, I am new to the site and I hope I can be of some help. I might have missed it in the previous emails but have you checked voltage at the IC Ignition switch on the outside of your distributor cap. I am referencing it there, since that is were mine is located. I had the exact same problem about six months ago and after replacing it, my Z is running fine. Hope this helps.

 

[ryanb80]

probably a typo, I could not remember the exact pin number.

The only problem I have is that I do not have a fuel pressure guage - good excuse to buy one I guess... hahaha.

I did not put fuel stabalizer in it, never have in the last 7 years of storing it for the winter, I have also let it sit a lot longer then I did this time - 6 months and it started fine.

I will get a pressure guage and test it.

thanks

 

[ryanb80]

I will try that

thanks

 

[Ron Diederich]

Ryan,
Check the fusible links , clean spade connections , replace plugs

Later
Ron

 

[DrX]

When I checked for fuel flow, I pulled the hose off the top of the fuel filter, had someone stand upfront and watch while I tapped the key. Fuel instantly started to flow upon tapping the key. Is this what you're doing to check for pressure? Remember, it's not going to be pressurized while the pump isnt running, and it only runs when the key is on. If I am stating the obvious here, which I probably am, sorry. I'm just not sure what you are saying in your post.