gas-saving tips

[wolfsreign]

so we need to clarify what were talking about, A/T or M/T
and on top of that, both trannys would need a vac on the line to test the intake (basically).
then both trannys would need a volt tester on the spark plugs, like a light, or led so see if it sparks or not, and on which tranny.

that will solve everything. hahahaha. anyone willing?

also, need the idle vac compared to "engine braking" vac reading.
~wolf.

[Davinci_360]

If you don't believe the factory service manual's description of how this works, I don't really know what to say ...

The idea here is that if a manual transmission is in gear, and you let the clutch out, without pushing the accelerator pedal, the engine will either die (if you're stopped), or slow the car down (if you're moving). This is because the ECU senses that the car is decellerating, and cuts pulses to the fuel injectors. I believe it cuts the spark as well, but that might just be because my car has a distributor - might not apply to other cars with different ignition systems.

The ECU also detects when the car is at an idle, and still sends enough gas to keep the engine running when you are in neutral. The engine idles freely because the momentum (or lack of momentum) isn't a factor - the transmission essentially isn't connected to the wheels.

On an automatic, you can still experience engine braking (try shifting to 2nd when going about 45 mph - it'll slow you down a lot). The engine will not die, though, because it's always turning the torque convertor.

Honestly, forget vacuum guages ... if the fuel injector isn't spraying, you aren't using gas - plain and simple.

[KING_3]

I think Davinci really makes sense. especially the comparison between M/T and A/T

one more question, suppose your car is running, you're in gear (manual tranny), then you turn the key off. What will happen? Has anyone tried this already? (don't want to try it unless i know what would happen )

based on what Davinci mentioned, I believe you won't feel anything

but if the following posts are true, then you will really need to turn the key off to save gas when decelerating

common sense says that if the ecu cut fuel the engine would die. the engine still has to maintain a propper air/fuel mixture to keep it running correctly. there is no way that it could cut the fuel off (imo).

if the engine cut fuel and spark then it would stop running. have you actally seen the injectors stop spraying and the spark plugs stop sparking?

the inject are always running as are the sperk plugs, when you are engine braking your thorlle body is in ilde posittion so it is only adding fuel it need for idle, so are you are actually caring the car oon the wrong mixture, but the ECU won't adjust it coz the TPS is saying it closed

[Davinci_360]

Again, I can only really vouch for my car - an '89 Lemans with the 1.6 8v throttle body injection. I have turned the ignition off while coasting down a long hill in gear, and the engine acts very much like i just took my foot off the accelerator. I've also had my car die coasting in gear, and essentially the same thing happened - engine braking. Eventually (if you don't turn the ignition back on) the car will slow down until it doesn't have the momentum to compress the air in the cylinder, and you'll stop.

The ECU doesn't just work off of the TPS sensor - there's quite a few more sensors that it uses to determine whether your car is at an idle or not - Vehicle speed sensor, reference from the distributor, etc.

[KING_3]

where do you think we can get information on the "programming of daewoo ECU's"
just so we'll know how the ECU analyses the inputs and how it reacts