Ghost in the Machine

[IamZHead]

Had a 72 240z in my early twenties – sold it to go back to school – 20 years later I buy a 76 280z. This one is special…but aren’t they all!!

Anyways – the history – after importing it into Canada and driving it for two Summer’s I am driving it to the garage for Winter storage, seriously.

Suddenly, I feel a loss of power (50%) when I accelerate...or effectively no power gain when I apply the gas – like there is air or a void when I press on the gas and nothing is burning at the cylinders...no RPM movement...jst dead air.

Pedal goes down but nothing happens. Car starts jerking a bit - it doesn't like this, and neither do I. With some slight gas pedal feathering I manage to get it to the garage and put her to bed – really wonky considering everything was working fine up until then.

Jump ahead one year – I have been buying some parts on Ebay over the winter...with the assistance of my local mechanic

- Put in new injectors

- Put in new fuel pump

- Put in a new AFM (That was an easy one haha)

We have spark, we have fuel pressure at the injectors, and now we have air.

I start her up she sounds great, I le ther idle for a bout twenty minutes – warms up – I ease her out things seem good then wham – gas pedal doesn’t seem to have any reaction - loss of power - progresss to no power

– I notice when I press on the gas pedal – there is the void and then she starts to die (idle drop)

- I release the pedal and she returns to a nice idle, press down and she dies, release she comes back

- regardless of gear 1st or reverse – cannot get her into 2nd and I cannot even move her from the her current position without her dying

- I turn her off and let her sit for about 10 minutes

- Engine is warm – start her up and shes fine – gas pedal works, RPMs work

This problem is intermittent and regardless of a cold or warm engine it occurs

I can’t seem to find out what is happening inside. I am a bit afraid to take her out on the street, until I find the bug.

EFI Relay?

Contact somewhere?

Has anyone had this happen to them or can they recommend a solution.

My mechanic is a bit stumped as well

We have not tried any ECU - voltmeter testing of all the relays etc

Please Winter is coming and I want to get her working

Thanks All

[240Z-Fan]

It sounds to me like you are having a fuel delivery problem. Possibly as simple as a plugged fuel filter. BTDT on a GMC Sonoma truck..

Low fuel flow will cause the dead feeling at higher throttle positions because it is too lean. Releasing the pedal brings the air flow back down to one that matches the fuel delivery.

I am guessing that the gas tank is rusted and the rust has collected in the filter. When you start it up, the fuel flow drives the particles up against the paper, eventually plugging it tight. Then, when you shut it off, the particles fall back down to the bottom effectively unplugging it. So when you restart it, it runs better for a while until it re-plugs itself. This is just a guess.

Try replacing your fuel filter. More importantly, cut open the old one and see what it looks like. If it is rust, you may need to have yours cleaned and sealed.

One more thing, your fuel pump may have a screen in it. It may need to be cleaned out as well. Someone else can chime in on that...

Al

[Zs-ondabrain]

Also, connect a "T" fitting to your fuel line on top and connect a pressure gauge of some sort with long lines so you can watch it while you drive. If the pressure stays up when there is a loss of power, then the problem is somewhere else.

I had an issue similar to yours and it turned out to be a Bad coil. Weird but true.

[EScanlon]

Vacuum advance mechanism in the distributor, check it.

E

[Z train]

It sounds to me like you are having a fuel delivery problem. Possibly as simple as a plugged fuel filter.

X2

Also, connect a "T" fitting to your fuel line on top and connect a pressure gauge of some sort with long lines so you can watch it while you drive. If the pressure stays up when there is a loss of power, then the problem is somewhere else.

And then,install the guage right off the "T" and leave it there.True about ignition issues masquerading as fuel issues.BUt the fuel filter is the easiest to deal with.And if the filter does solve your issue,you then need to drop the tank and douche it out real good.

[mlc240z]

What is this obsession with douching???!!!

But what he said.

[IamZHead]

Thanks All

The fuel filter was replaced and when we tore it open the old one it was "half full" of what I would call a fine, almost clay-like particles - could have been rust...could have been sabotage. But who would do something like that to a machine like this !!!

I really got to get a locking gas cap.

I am going to look into the tank cleaning as well - I have a new coil so that is one is on the agenda - I am thinking about bringing out the OHM meter and going into ECU diagnostics - I picked up the EFI book and its a good read.

As for the rest I am going to mention it to my mechanic as ideas.

I must say I am gettign a bit discouraged - never had this issue with the carb set up in the 72 240Z

Fact is there are no Z's up here anymore and no Z mechanics

God Bless!!