280Z rebuilt fuel system - engine just stops!!!

[Zed Head]

Maybe it's not the fuel system at all.  The recent work there might be drawing too much attention.  Failing fuel systems usually give a clue since the engine dies due to low pressure.  There's usually sputtering and low power before shut-off.  Your clues seem electrical .

Since you have lots of time while waiting for things to cool down you should be able to get out a meter and/or some noid lights or test lights and check the things that need power and ground.  Check for power at the coil, power at the injectors, injector activation when the engine is spinning, and spark.  Narrow the possibilities down.

If everything checks out then you'll have to consider the dreaded but not unheard of ECU failure.  I've mentioned before in long past posts that I had a 78 ECU die on me while I was giving it a test run.  Just died instantly, restarted, after a few seconds, let me drive another mile, then died again.  I put the old 76 ECU back in and everything was fine.  After that adventure I always carried a spare ECU behind the seat.  

The other common failure point is the ignition module.  But you'll get pointed that way if you have no spark.

 

[widget777]

Just replaced the fuel filter yesterday and still had the same symptoms. Fuel pressure looks good when teh engine fails

[Zed Head]

Do you have a meter or test light?  Check the coil positive post for power with the key on.

[widget777]

I will do that. Last night we were waiting for the engine to fail and noticed that the coil was warm to the touch???? I changed that coil  out with the original OEM coil and could not start the engine. The pump was working and there was normal pressure in the fuel manifold. The engine spun up like there was no spark or the fuel was not getting to thru the injectors, so I gave up for the evening. I want to change back to the aftermarket coil before I do anything else. Then I will check if there current to the + post of the coil. I also will see if there is spark from the wire leading to the distributor. I have church tonight but will play with the car tomorrow. Thanks for your interest and help. Did you have any thoughts about my question regarding the sensors in the thermostat housing???

[widget777]

I have 10.6 volts on the + post and 12.6 across my battery posts. I just started the engine and it started immediatly. I keep thinking that the problem is engine temperature related.

[Zed Head]

You have to do the testing when it's not working.  

[Captain Obvious]

Well it sounds like you have narrowed the issue down to an ignition electrical issue, and not fuel. That's a big step.

So it may be temperature related, but at least we know it's not (directly) related to the fuel supply.

On 1/26/2025 at 6:41 PM, widget777 said:

there are 2 sensing devices on the thermostat housing. Could either of those be the cause when the engine comes up to temp??

Can you post a pic of your thermostat housing?

 

[widget777]

There is too much equipment around the thermostat housing to get a clear picture. I have attached a diagram of the housing and various sensors that could be installed. I have all sensors except the  water temperature switch in my thermostat housing assembly,

IMG_0814.HEIC

[Captain Obvious]

Sorry, but I can't view that attachment. Whatever format that is, my system can't deal.

Can you post a .jpg or a .pdf?

[SteveJ]

2 hours ago, Captain Obvious said:

Sorry, but I can't view that attachment. Whatever format that is, my system can't deal.

Can you post a .jpg or a .pdf?

Are you on your flip phone again?

[widget777]

Not sure what you are asking. My phone is 360-220-0799 if you want to chat.

[widget777]

Sorry for the confusion. I have saved teh attachment as a .pdf file so you should be able to open it. Let me know if you are still having problems.IMG_0814.HEIC.pdf