Several Questions

[Devy]

Hi!

My main question is about closed loop mode of the EP91! I tinkered o lot with lambda sondes and lambda gauges. I installed one to my EP91.

Does somebody know, whether the EP91 goes into a real closed loop mode? Realtime? My impression is, it does not!?!?

The point is: i installed a fuel pressure regulator. And no matter in which direction I change fuel pressure (and therefore air-fuel-rati) the ECU does not seem to regulate against it.

[jezza323]

closed loop only happens on light load cruising, it will not make a difference when the car is under load (accelerating/on boost)

[Devy]

yes, but does the EP91 have a realtime closed loop mode? Or is it only a kind of "self-learning" correction to the actual map (as previously discussed)?

[HardcoreEP]

The car will not immediately make changes unless the fueling is outside of its parameters. What will happen is that over time the ECU will try to compensate. If it cannot it will simply go into limp mode and run rich all the time. The car also doesn't alter fueling alone, it will use timing to make changes as well.

[Devy]

@HardcoreEP

You are the man. I thank you very much!

This is exactly what i see. My purpose is (I have a 4E-FE - without turbo), to save some fuel.

I installed an LC-1 Lambda sensor kit. This is a programmable wideband-sensor, which can exactly measure airfuel-ratio. I programmed it to simulate a lambda value of lambda 0,9 when the car has Lambda 1,0 (=14,7AFR). I hoped, that the ECU regulates against it and the enigne runs at 15,5 or 16AFR, meaning at the point of its lowest fuel consumption. But i saw immediately: It does not.

What i did: bought fuel pressure regulator, lowered fuel pressure to 32 psi and it runs at lambda 1,1 most of the time.

What i want to do now additionally is: advance ignition from 10° to arround 13-15° to compensate the slower combustion speed and take full advance for fuelsaving.

what do you think?

[HardcoreEP]

Since the car is NA then the advance in timing wouldn't hurt. I doubt the FE's ignition tables are as aggressive as the FTE.

[ivan]

Also im am guessing a device like SAFC will help you reduce fuel consumption that you can tune using your LC1.

Hope it helps,
Ivan

[Devy]

Also im am guessing a device like SAFC will help you reduce fuel consumption that you can tune using your LC1.

Hope it helps,
Ivan


Very nice apparat! Thank you for this hint....

My 4E-FE is without turbo, as far as i know it has no air-mass sensor. But there is a senor in the airbox...i wonder if this is a temperature or pressure sensor?
I also wonder how much influence this senor has compared to Lambda concering AFR....

[HardcoreEP]

The sensor in the airbox is the air temp sensor. The MAP sensor is on the firewall.

[ivan]

Map sensor on 4efe engines does not read positive pressure either :)

[Devy]

yes indeed....
i took a deeper look and the sensor on the firewall says: VACCUM SENSOR.