TomoHawk

Is that tight?  IIRC, the brown one is for the headlamps, so you want to make sure that is the correct size.  It looks a bit thin.

The only way(s) to see if it's sticking and why is to remover the AFM and look inside, or take the cover off the side.

It looks like you could only make changes to how the L-Jet ECU works if you had the original Bosch circuit diagrams and operation flowchart.  But at least you can fool around with small changes in the coolant sensor.

If you are interested in a less electronic way to tune the fuel injection, Autospeed.com has some good technical articles you read and try:  One uses an accelerometer in stead of the S-O-P  method.

BTW-  the accelerometer is also useful for determining shift points.

https://www.autospeed.com

1 hour ago, chaseincats said:

 

7 hours ago, chaseincats said:

I thought the ecu (fuel injection brain if you don't want to call it that) was a bunch of microswitches on the s30s, no?

@madkawThat's an interesting idea with the afm sticking.  I don't want to switch the car to megasquirt because it runs fantastically 95% of the time especially after this tuning thread.

You must be thinking of old computer peripheral or I/O adapter cards, that use the microswitches to set up the port settings, card address, etc.

On 6/27/2021 at 7:25 PM, Patcon said:

Get some compressed air and cool the ECU when it does it and see what happens

You can get a cryo-freeze spray for electronics, but I don't know who sells that now.

5 minutes ago, Captain Obvious said:

There are no switches (electro-mechanical devices) inside the ECU. There are lots of transistors (which can be used to "switch" current paths, but there is nothing elecrro-mechanical. Nothing moves inside the box except electrons.

And as for it being a "computer" or not... I would say "not".

Well...  there is that one big integrated circuit in a metal can which does all the complicated stuff.

When I had computer 101, we learned that a computer had a CPU, short-term memory (RAM), long-term memory (hard/floppy drive) and can start & stop programs at will until you turned it off.  Micrprocessors in cars are similar because they have a CPU and memory (RAM and flash memory) ( think of the Arduino things) and only operate one kind or system or devices in a vehicle (engine, transmission, electrical (lights/security/heat/windows) entertainment, etc.  Each begins running a single, but very sophisticated, program when you turn on the main power, and runs it until the power is turned off.

If you want to measure temperature, you use a temperature sensor or thermometer, and read the value directly, the same for pH (of a water or liquid) to directly measure pH., a pressure sensor or gauge to directly measure pressure, etc., but there is nothing like a sensor that directly measures the air-to-fuel ratio in the cylinder.

They use the oxygen sensor and presume that if there is no oxygen in the exhaust gas, it must mean a 14.7 air/fuel mixture.  So you could calibrate the ECU to any oxygen value and make it mean 14.7, then complain the engine runs badly!

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.