TomoHawk

27 minutes ago, chaseincats said:

"Lean boot" is a term coined by @Captain Obvious earlier in this thread to describe the car inexplicably running lean at startup.

That's strange.  Since the coolant is cold, the mixture ought to be a bit rich.  Please explain how you can get a lean condition for a cold engine, unless it was stopped in a warm state, then retarted before it could cool.

I still don't understand how you can tell the exact air-to-fuel mixture going into the cylinders by measuring the oxygen in the exhaust gas in the exhaust pipe.  There is no such thing as a sensor that measures the air-to-fuel ratio directly so you can show it on a guage, so you are making a lot of big presumptions, as well as presuming the engine is in perfect working order, a complete combustion, etc.

You can measure the amount of air using the density sensor and air speed sensors, and the amount of fuel (approximately) using the fuel pressure and injector timing, then making some calculations to calculate the air/fuel ratio. 

I had an old AFM that had a dead sopt in the resistive track.  there was no way to fix it or revive it.  Another AFM fixed that.

9 hours ago, chaseincats said:

 

  I'll try to give the computer a smack

S30s don't have computers in them, unlessz you install something.  Neither to modern vehicles; hey have micrcontrollers  The Bosh L-Ject ECU is just a circuit board with transistors, integrated cir cuits, and other discreet electronics.

The only place you can accurately measure the air-to-fuel ratio of what goes into the cylinders is to put a sensor into the intake manifold.  Even more precisely, is to have a sensor near each intake port.  Having an o-2 sensor (whatever "0-2" means) only measures o-2 in that particular spot.

I stand by my original statement that there is npo such thing as a sensor that measures the air-to-fuel ratio, in the intake manifold.

Is the AFM even connected?  The connection is underneath..It might need to be cleaned with DEOXIT,  not WD-40.  Make sure the throttle linkage is connected and functioning as well.  You can operate the throttle by hand.

42 minutes ago, chaseincats said:

It has an oxygen sensor ("o2 sensor") that is welded into your exhaust.  All modern cars have this.

Oxygen sensors measure oxygen.  How does the oxygen measure the fuel mixture in the intake manifold?

There's no such thing as an air/fuel sensor. How does that gause operate?

Personally, I'm happy that there is still enthusiasm for these cars.  Most people I know have ditched their S30 for a Nissan or infinity, or some other new model, because you just putin newq parts if something fails.

Sorry, I don't smoke. 😉

He offered to do for free, which is why I let him try it.  So it wasn't a good deal, even for free.

2 hours ago, chaseincats said:

I'm pretty sure he's talking about the aux air regulator. 

I'd expect an 'expert' to know the difference, especially since kept mention 'idle air motor' and he also called the ECU a 'computer.' 

OH-  Sorry mate.

I had my car in a shop to have the "datsun expert" check for vacuum leaks, and the first thing the guy told me when I went back was  that the ECU w3as not original (It was) and the "idle air motor" was missing.  The L28 does not have an idle air motor, whatever that is, nor would it be connected to the ECU.

Right, the ECU does not controll the Aux air valve.  It's connected to the thermotime switch and coolant system.

I woulden't let that crazy guy stand in my driveway.

I use aftermarket (JY) seats that are recovered, and have foam added for bolstering, but it's not enough when you go to autocross or any other performance-type event.

That's the problem. to attach something to the back of a cloth seat that doesn't ruin the custom work, looks like it belongs, or won't fall off if you accidentally tug on it, and has a slot to put the strap through or in.

BTW - this is also called a Torso Strap.  G-Force sells them, and it's just a strap made from Nylon webbing with a big plastic pinch clip.  They just sell them, and don't tell you how it's used or installed.

On 5/5/2019 at 7:05 AM, grannyknot said:

This will do the trick,

 

The duct tape would be fine if tyou had vinyl seats, but my seats are cloth, so I would need something that will not tear or mar  the fabric or fall off.

Thanks a lot.  I just haven't seen one under there, and I've been under there a lot.

In section EF (Engine Fuel) it connects to pins 9 & 12.  The sensors don't use a common +12V, so the ECU is supplying the 12V on one pin.

There are several vacuum hoses;  one to the brake booster, one to the heater controls, and one to the distributor.

Is there a photo of the altitude switch?  Searching only turns up wiring diagrams, and there wasn't one on eBum, but I think it has a cylindrical body...

4 hours ago, chaseincats said:

use a test light to see if it's getting power with the car running

So one terminal will have power, and the other goes to ground or the ECU?

On 11/27/2020 at 5:05 PM, chaseincats said:

If your bypass switch is working, you will notice the following with the car warmed up and any vacuum line unplugged:

If I did that, I'm pretty sure the engine would stall.  Would you please explain what "any vacuum line unplugged" means?

I keep forgetting, I have the Federal ECU... 

Oh well.  I  can just set the heater to 'floor' which means I get a vacuum leak from the brittle dashpot hose (heater guy just cuts & splices the hose instead of replacing it!) and that will throw the AFM off to cause a lean condition.  Or... I could add an electric valve to add air to the intake, post-AFM...

I suppose that is what the altitude detector does: it leans the mix.  it's a switch connected to a small bellows.

But I forget:  should you use your regular fuel, or change octane for higher elevations?

I was also thinking that you could substitute a switch to get extra MPG on the interstate.  Just don't forget to go back to the correct mix ratio for passing or city streets!

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