I'm saving gas!

[DivideBYZero]

Originally posted by: Truenofan
Zenmervolt, give me, what you call a "reputable" source, and enlighten me, instead of stating that im wrong.(it helps when you can prove what you say, instead of saying it, i dont know who you are, if you have any kind of degree's in anything at all. so unless you can prove it, im taking what you say with a grain of salt.)

edit: btw, i know my car still uses gas when im engine braking, im also going to go for automotive repair/tuning when i go to school when i get out.(i plan on doing my own tuning on a standalone system on my car.)

Page seven.

 

[exdeath]

Originally posted by: Truenofan
Zenmervolt, give me, what you call a "reputable" source, and enlighten me, instead of stating that im wrong.(it helps when you can prove what you say, instead of saying it, i dont know who you are, if you have any kind of degree's in anything at all. so unless you can prove it, im taking what you say with a grain of salt.)

edit: btw, i know my car still uses gas when im engine braking, im also going to go for automotive repair/tuning when i go to school when i get out.(i plan on doing my own tuning on a standalone system on my car.)

Prove it yourself and log the injector cycles. Or just observe a test light on one of the injector plugs when you open and hold the throttle linkage then quickly slam the throttle shut. It won't be in gear coasting, but the condition of TPS==0 && RPM > IDLE will still be met for a brief instant and the light shouldn't pulse (will be off or steady on but not pulsing) at all between the time you shut the throttle and the time it takes the RPM to fall to idle.

 

[exdeath]

Originally posted by: Rubycon

Originally posted by: Zenmervolt

Spark power is fixed. It is not load or RPM dependent.

What you're hearing through the AM radio is not from the spark, but rather the injector pulses. These will increase as the injector duty cycle is increased to supply extra fuel as the throttle is opened.

ZV

Ok that makes sense as I was wondering what increasing spark power would really do. (I'm not up on cars)

What kind of signal do the injectors get?

Pulse width modulation. Injectors are either on or off, it's actually the fuel pump pressure that is injecting the fuel, not the injectors. How long the injectors are open determine fuel amount.

http://www.picotech.com/auto/w...injector_4channel.html

The flat part on the bottom of the pulse is the open duration and the large upward spike is to quickly slam them shut to overcome the fuel flow. It takes more power to initially close them from an open state against the fuel flow than it does to keep them closed. This is just the raw computer signal and if I recall is actually inverted? Being that fuel pressure remains when the key is turned off, the injectors are normally closed with no power.

It appears this is a capture of r-L-r-r-L-r-L-L showing the uneven firing that gives the V8 it's much beloved burble sound.

 

[Zenmervolt]

Originally posted by: Truenofan
Zenmervolt, give me, what you call a "reputable" source, and enlighten me, instead of stating that im wrong.(it helps when you can prove what you say, instead of saying it, i dont know who you are, if you have any kind of degree's in anything at all. so unless you can prove it, im taking what you say with a grain of salt.)

edit: btw, i know my car still uses gas when im engine braking, im also going to go for automotive repair/tuning when i go to school when i get out.(i plan on doing my own tuning on a standalone system on my car.)

http://frwilk.com/944dme/shudder.htm

Bosch has used this programming in all Motronic ECUs. When RPM > XXXX (where XXXX is an arbitrary number determined by emissions controls, typically around 1,500 +/- 250 RPM) and TPS reads a closed throttle, the signal to the injectors is killed and no fuel is injected. When coasting down to a stop in gear on my 951, there is a noticeable "surge" as the 1,600 RPM mark is passed and fuel flow to the engine is resumed (the 951 is set to resume injection at 1,600 RPM with the throttle closed).

I say again, you're wrong. One of the links you posted as "evidence" actually showed that you were wrong. There are two other highly experienced people in this thread who have also shown that you're wrong. Why you need additional proof is beyond me, but you have it above.

ZV

 

[Rubycon]

Originally posted by: exdeath

Pulse width modulation. Injectors are either on or off, it's actually the fuel pump pressure that is injecting the fuel, not the injectors. How long the injectors are open determine fuel amount.

http://www.picotech.com/auto/w...injector_4channel.html

The flat part on the bottom of the pulse is the open duration and the large upward spike is to quickly slam them shut to overcome the fuel flow. It takes more power to initially close them from an open state against the fuel flow than it does to keep them closed. This is just the raw computer signal and if I recall is actually inverted? Being that fuel pressure remains when the key is turned off, the injectors are normally closed with no power.

It appears this is a capture of r-L-r-r-L-r-L-L showing the uneven firing that gives the V8 it's much beloved burble sound.

Nice info. Thanks!

 

[DaWhim]

coasting in neutral saves gas for me, at least in my automatic car.

I have a Scangauge II track my mpg and car condition.

 

[imported_Truenofan]

hey, all i was sayin is give me a reputable source, and from reading, im wrong. according to piston powered vehicles, im pretty sure that my car(rotary driven) doesnt do this but i can still be wrong, because running any kind of lean on that engine, will cause excessive wear on the housings/apex seals and increase wear and eventually premature destruction of the engine(they can go in excess of 200K miles before compression starts going down on the motor on n/a's). i'll have to wait till i get back from iraq to do the tuning on my car, gotta replace all the hoses and fluids before all that as well.

 

[91TTZ]

Originally posted by: Zenmervolt

Spark power is fixed. It is not load or RPM dependent.

What you're hearing through the AM radio is not from the spark, but rather the injector pulses. These will increase as the injector duty cycle is increased to supply extra fuel as the throttle is opened.

ZV

On my car, the spark power isn't fixed. The ECU can control the intensity, duration, and dwell of the spark. Under heavy load the intensity increases.

 

[Zenmervolt]

Originally posted by: 91TTZ

Originally posted by: Zenmervolt

Spark power is fixed. It is not load or RPM dependent.

What you're hearing through the AM radio is not from the spark, but rather the injector pulses. These will increase as the injector duty cycle is increased to supply extra fuel as the throttle is opened.

ZV

On my car, the spark power isn't fixed. The ECU can control the intensity, duration, and dwell of the spark. Under heavy load the intensity increases.

Most of my cars still use a traditional coil and distributor, so no adjustment to intensity, the coil supplies what it supplies and that's fixed. I'm not used to all these new and fancy do-dads. 😛

ZV

 

[91TTZ]

Originally posted by: Zenmervolt

Most of my cars still use a traditional coil and distributor, so no adjustment to intensity, the coil supplies what it supplies and that's fixed. I'm not used to all these new and fancy do-dads. 😛

ZV

Yeah, Nissan put a lot of fancy doo dads on he Z.

 

[fornax]

Originally posted by: Zenmervolt

Wrong. Modern EFI engines turn off ALL fuel injection when engine braking regardless of RPM.

ZV

How modern is "modern"? 1985 and later? 1995 and later? 2005 and later?

 

[Zenmervolt]

Originally posted by: 91TTZ

Originally posted by: Zenmervolt

Most of my cars still use a traditional coil and distributor, so no adjustment to intensity, the coil supplies what it supplies and that's fixed. I'm not used to all these new and fancy do-dads. 😛

ZV

Yeah, Nissan put a lot of fancy doo dads on he Z.

Anyone who doesn't love the old 300ZX Turbo doesn't love cars. Late 80's and early 90's were a hayday for sportscars...

300ZX TT
RX-7 TT
Supra TT
3000 GT VR-4
944 Turbo S
964 Turbo

All within the reach of a reasonably successful person if he (or she) was willing to make a couple sacrifices in other areas for the cars.

ZV