SadZGuy

1978 280z No Start, No fuel injector pulse

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    Hello all, a couple months ago I purchased a 1978 280z that had been sitting since 2001. I started by cleaning and coating the inside of the tank, installed a new fuel pump, installed an extra fuel filter near the tank, and replaced the fuel filter in the engine bay. I also have a new fuel relay, efi wiring harness, ecu, and a new 3 terminal dropping resistor (the 5 terminal and new 3 terminal resistors tested good with a multi meter). I also replaced the spark plugs, spark plug wires, and the pickup wire from the coil to the ditributor.

    When I try to start the car with starting fluid it will run but only when there is starting fluid present. I'm sure this means that I have good spark. So my problem is fuel.

    When I did the FSM tests with a multimeter at the harness connector every cylinder checked out good. Each cylinder read the battery voltage meaning the dropping resistors and injectors have continuity from the battery and are good. I can also hear the fuel injectors click when I ground them through the negative wire on the coil. I can also hear the relays give a solid click when I turn the key to start. The power line from the battery to the ecu and the revolution trigger signal all read battery voltage as well and all my grounds also tested good. I know I am getting fresh fuel to the fuel rail because when I pulled on the inlet fuel rail line there was a bunch of fuel that squirted out. At first given all the successful tests, I thought I had a bad ecu, however I just tried starting the car with a new working ecu for the second time and it still wont run.

    I went and read many posts on so many forums and scoured the internet to find a solution to my problem before wasting someones time and posting about it. However, I am stuck here and dont know what to do anymore. Even though I prefer EFI, I'm thinking of just switching to carbs because no matter what I do the damn thing seems to never want to run.

    I did all my tests and checks but to no avail.
    And yes the tach is plugged in.
    Any help? I'm desperate to see this thing running.

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    20 minutes ago, SadZGuy said:

    . I know I am getting fresh fuel to the fuel rail because when I pulled on the inlet fuel rail line there was a bunch of fuel that squirted out. 

    Everything that you have done looks right. Very thorough.  The one thing that is missing is an actual fuel pressure number.  You can have squirting at 2 psi, which might not be enough to keep the engine running.  

    It is also possible to connect the hoses to the rail backward.  This will give pressure between the rail and the filter/pump but no fuel flow through the rail.  I would confirm that the hoses are connected correctly and measure fuel pressure.  If the rail is connected backward you'll get maximum pressure from the pump, about 90 psi. if it's aftermarket, but no fuel to the injectors.

    On the 78 model the easy way to get power to the pump is to disconnect the oil pump sensor and turn the key to Run.  The pump will get power.  It's a flaw in the system design but convenient for testing.

    Edited by Zed Head

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    59 minutes ago, SadZGuy said:

     I can also hear the fuel injectors click when I ground them through the negative wire on the coil. 

    Also, your title says "no pulse" but you said that you can hear them click when you "ground them through the coil".  I assume that means you're grounding the coil negative with the key on and every third spark makes the injectors click.  But maybe it means something else.  That would mean that the ECU is working as it should and Pin 1 is connected.

     

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    Thanks Zed Head, I ordered a fuel pressure gauge and I will update you with my readings. Also the the fuel rail is connected correctly to the inlet and outlet fuel lines. Until I get the fuel pressure gauge I will continue testing some more and will update if I find anything new. I hope this car starts running soon, I feel like the problem is something very small and easy because I have replaced most of the EFI and fuel related components at this point.

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    The 280Z Fuel Ijecion manual has a good troulehooting flowchart, and pecs.

    • Like 2

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    1 hour ago, Zed Head said:

    Also, your title says "no pulse" but you said that you can hear them click when you "ground them through the coil".  I assume that means you're grounding the coil negative with the key on and every third spark makes the injectors click.  But maybe it means something else.  That would mean that the ECU is working as it should and Pin 1 is connected.

     

    You are completely right, I have no idea how I was led to believe it was a bad ECU. I just checked using a noid light and when I try to fire her up the light pulses. So at this point I am thinking it is still fuel related but nothing EFI related, which I am glad to finally hear.

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    Could the injectors and their hoses still have old bad fuel in them?  Looks like you cleaned the tank and have had the pump running.  But if you look at how the rail is set up the injectors and their hoses are dead zones as the new fuel passes by them.  Don't know how long you've been trying but it might be that you just need to get some good fresh gasoline down to the injectors.

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    Could be the tps or afm are stuck from spider webs or something. The sweeper vane under the black square on the afm should move freely. Throttle position switch should go from right contact to free in the middle then to wide open left side.

    I've read that after washing the engine bay down the tps will stay wet and cause problems. Just guessing.

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    Finally, don't forget that all air entering the intake system must pass through the AFM.  The PCV system needs to be intact, all of the hoses need to be connected, and the big hoses at the AFM need to be hole free. The engine crankcase has to be completely sealed, no little air filters on the valve cover either.  Any extra air can make the mixture too lean.

    • Like 1

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    Lastly, finally, one more, sometimes an ignition module can put out a spark that is only strong enough for starting fluid.  Make sure you have a strong spark.

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    1 hour ago, Zed Head said:

    Lastly, finally, one more, sometimes an ignition module can put out a spark that is only strong enough for starting fluid.  Make sure you have a strong spark.

    OK SO.... apparently I didn't have any fuel in the system to begin with because I just put some in and it runs (awfully). HOWEVER, I was having legitimate ecu problems and I specifically remember having fuel in it when I tested the 1st ecu (swapped ECUs to confirm this and the 1st ecu still didn't work on the car nor did it fire the injectors when the coil was grounded). The problem was that I completely forgotten that I had drained the gas tank to rearrange fuel lines somewhere in between ordering the second ECU. So I actually did have a bad ecu at first but now its running with the new ECU and with some gas in it (who would've thought....). Even though its running it only starts with much cranking and wont stay running for long (i also hear squeaking noise, could this be a vacuum leak?) and also there is white-ish smoke coming from the tailpipe. 

    Anyways thanks for the help, probably wouldn't have remembered about the gas if you hadn't told me to check the fuel inlet.

    I'm gonna continue looking through these forums for help on these new problems since you guys have an invaluable amount of Z knowledge!

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    Getting these things to run well is just a collection of small things.  Crank open the idle speed screw and let it run and warm up while you check things.  A piece of water hose is a good directional antenna for your ear.  If it has oil and water it will probably be fine no matter how bad it runs.  They're pretty tough engines.  Watch oil pressure and temperature.  Check your timing.  Rev the engine and see if timing advances.  You can spend hours doing "stuff".

    I used to have a 6 foot piece of flexible plastic drainpipe that I put over the exhaust pipe and ran under the garage door.

    Edited by Zed Head

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    16 hours ago, siteunseen said:

    Squeaking could be the alternator belt or the water pump. Are you sure you have coolant? :ph34r:

    Yep there is coolant and the water pump is new but maybe I got one with a bad bearing? It sounds like the noise is coming from the water pump area.

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    16 hours ago, Zed Head said:

    Getting these things to run well is just a collection of small things.  Crank open the idle speed screw and let it run and warm up while you check things.  A piece of water hose is a good directional antenna for your ear.  If it has oil and water it will probably be fine no matter how bad it runs.  They're pretty tough engines.  Watch oil pressure and temperature.  Check your timing.  Rev the engine and see if timing advances.  You can spend hours doing "stuff".

    I used to have a 6 foot piece of flexible plastic drainpipe that I put over the exhaust pipe and ran under the garage door.

    Ok, I'm gonna try this out but I also think my temp sender might be bad as well.

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