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Trouble Starting


Yoak

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I have a 79 280ZX

 

Lately it has been having problems starting unless I floor it...

 

and then it sometimes one start.....

 

 

I have noticed though when it dosen't start if i take one of my extra plus and hook it up to the spark plug wires and set it on the valve cover it will then start...

 

Is this a grounding issue? Distributor?

 

Everything is stock except a new coil and a FPR

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fuel draining from lines? Will start if it catches on whats in the bowl if it hasn't evaporated, but if it doesn't needs to wait till fuel gets back to carby (if it has one?) Sorry don't know much about L series engines, just bought a 240z and am probably going with an rb

If it is carby fed and the lines are draining check if there is an external diaphragm, or check valve between the fuel line from the tank and the fuel pump. To see if it is working blow through it. You should be able to blow through from one direction but not the other. If you can blow through it in both directions it's stuffed. Worth a look?

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I think you should replace the wires too. Are the plugs fouled? (black) Oh.. are they gaped properly? When it does start, does it run fine? Or does it smoke black and idle all over the place? Holding the throttle wide open sholuld tell the ECU to cut the injectors (I think.. to prevent flooding) but here'a the thing; I had an 81 do that to me of and on.. I sold it in the end, but the guy I sold it to figured it out. An injector was 'stuck' open so it was screwing up evrything. Fuel presure wouldn't build properly, O2 sensor picked up LOTS of fuel so it cut back the injectors, ect ect. I actually did the same thing you did, but didn't figure it out at the time. By mistake, I forgot to put the plug back in and strted the motor. IT STARTED AND RAN!!! Lots of fuel came spraying out of the plug hole mid you.. If you pulled the plug from the cyl that had the bad injector, and it started, that might be the problem.

 

ALSO.. check the rubber AFM boot for cracks as it's AFTER the sensor, and will throw evrything out of whack. Oh, and check the 'little black box' on the distributor. (ign. module) Sometimes they go bad, and cause problems like this.. You'll need a multimeter and a manual.. I'm pretty sure there is a proper resistance measurement.

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Alright Here is an update.

 

NEW Coil

New Plugs

New Injectors

NEW Injectors

Replaced Cold Start Injector

NEW Cap & Rotor

Wires are NGK

 

Replaced original IGN Coil, however I suspect this one may still be bad or going bad....

 

 

I have a spare ecu ive tried also....same results

 

There is NO smoke coming from the car...

 

Any other ideas? New Distributor? or Thermo Switch?

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Is fuel getting to the intake?

In some models when you turn the ignition to Accesories the fuel pump pumps a bit of fuel, you can ususally hear it when you turn the key, check it is working and try doing it several times? I used to have to do that on a falcon of mine.

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There may be a potential issue there, I need to recheck this though, as it is hard to hear the pump in the car...

 

Car is also having trouble keeping a steady idle....if you rev car...when ideling back down it will drop below 500 and then bonce to 1000 and will continue to bounce untill stable

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hey ok i knwo this will sound crazy but try it. my 81 is doing the same thing i thought it was the cold start liek i said on here but i was wrong. i turn the key till i hear the realy and fuel pump stay on(right b4 starter kicks) leav eit there for about a second then crank it for about .5 to 1 second let off. if i do that mine fires right up idk why

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