Constructing a sinewave generator for idle leanburn

[greasemonkee]

With the 48 state VX ecu leanburn kicks out at about 1 or 2 mph at idle rpm. Are there any electronic folks in here willing to disclose plans for a sine wave generator to mimic the speed sensor at the flip of a switch? I'm not sure of the voltage or frequency yet. Has anyone attempted this?

It would be nice to flip a SPDT 2 position switch at stop lights or coasting while idling activating a sine wave generator which mimics the VSS at X mph.

I'll take care of the other condition which must be met to activate leanburn - the TPS and more airflow - with a pneumatic cylinder and air solenoid operated by vacuum pushing the throttle just off its idle position.


Wonder if this would trick the ecu allowing for leanburn in 1st gear? I wonder how much gear correction takes place in the fuel/ignition maps - adverse effects of a VSS simulator being left on?

[JasonG]

On most vehicles the VSS is a pulse signal not a sine wave.
This is good as they are simpler to build.
Google "555 timer" for more circuits than you can imagine.
Thay are simple and cheap.

Instead of moving the throttle with a solenoid, why not just use a pull up resistor ?
There's a good article here: Browser Warning

[greasemonkee]

Interesting, a pulse would be nice. However, the idle airflow in leanburn must be increased to maintain idle rpm otherwise you'll have a perpetual surge situation.

Thanks for the link

[drmiller100]

the tps has two signals - an idle signal and an actual tps rheostat.

if rpm goes to high at "idle" the ecu will cut fuel to the injectors to keep idle rpm causing annoying surge.

[JasonG]

Originally Posted by greasemonkee

Interesting, a pulse would be nice. However, the idle airflow in leanburn must be increased to maintain idle rpm otherwise you'll have a perpetual surge situation.

Thanks for the link

I believe you misunderstood my post.

The pulse from the 555 timer is to replace the VSS signal.
This is to make the ECU think the car is going X MPH not the actual speed.

The drmiller is partly right, increasing the idle air will cause the ECU to decrease fuel to lower the idle, but only to a point.
The ECU has a minimum setting it won't go below. I got a good lesson in this when my IAC valve went bad. Thought for sure I had an intake leak. Couldn't get the idle down. But it idled smoothly.

Now, if you depressed the MAF reading so it didn't know about the extra air...........

Under load this could swiss cheese a piston, not like I've ever done that while on I-95

EDIT:
My god man, I just realized we're talking about a Honda !
Check the tuner sites, there's a few cheap programs to re-program your fuel maps.
Hond decided not to encrypt the computers so anyone can rewrite them.

WOW, way past my bed time to have missed that.

[greasemonkee]

Most of my posts these days are mad far beyond my bedtime as well, no sweat, but thanks for the effort. The P07 ecu's code is the least understood of all, and to my knowledge, not one has unscrambled it, in part to it's dual eproms? I had an idea at one point to tune a vtec-e to eliminate the emissions hindrances of economy, but realistically the dyno hours and cost of hardware and more software licenses would be astronomical from the economy enthusiast' perspective. Tricking the ecu seems to the reasonable solution.