Safe lean cruise.

[apeman69]

No CEL if you disconnect the heater circuit so don't even worry about it.
Tried this with narrowband emulation connected and not connected, no CEL. No difference how long car is idling or driving.
ECU can't be checking for sound heater circuit (on PFL auto at least).

Sent from my Huge Brain using MyFingers

[paulg23]

No CEL at all. Done about a 1000 miles with it like this.

[lateshow]

With open loop there comes a situation where going downhill AFR goes 16-20. I've got 14.4 on the smallest load column. Should I be worried? Has Kenneth examined closed loop, how does it function? Because it seems that when using only open loop the car is more eager to turn injection off. Fuel consumption was 9.6 l /100km with the first tank (29.4 MPG) Most of this was driving @ 100kph, a part driving 80kph, very little city driving.

[Kenneth]

Is that from wideband? If you don't have your foot on the accelerator, you should be getting maximum lean (injectors off).
If you DO have your foot on the accelerator then that is a bit on the lean side...

No, I haven't really looked at the closed loop section in the ECU.

With open loop there comes a situation where going downhill AFR goes 16-20. I've got 14.4 on the smallest load column. Should I be worried? Has Kenneth examined closed loop, how does it function? Because it seems that when using only open loop the car is more eager to turn injection off. Fuel consumption was 9.6 l /100km with the first tank (29.4 MPG) Most of this was driving @ 100kph, a part driving 80kph, very little city driving.

[lateshow]

Yes that is from wideband, i have my foot on accelerator when going down very steep hills so I'm thinking if it goes on /off with injectors somehow (the actual momentary AFR isnt between 16-20, it is more like 15.5 and then injectors off and the same loop again and the wideband reacts to it that way) OR then there is some point between load 0-10 where open loop doesn't function well and it drops the AFR to too lean for bigger value of time and it will break my engine somehow?

[taylor]

I had a microcontroller in my car to read the 0-5v output from the wideband and simulating a narrowband on a output pin. I could adjust the switching poing by changing the code, I drove frome christchurch to auckland (~1000KM) with it targeting between 16.5 and 17.

Fule consumption wasnt bad, got about 570km to a tank, not bad considering I did alot of passing

[MackTheKnife]

Thanks to all that confirmed that removing the O2 sensor heater wires won't trigger a CEL.

I left them connected after reading feedback from Evo owners, but now I can shed a few grams of surplus weight from the car next time it's off the ground.

[phosty]

I had a microcontroller in my car to read the 0-5v output from the wideband and simulating a narrowband on a output pin. I could adjust the switching poing by changing the code, I drove frome christchurch to auckland (~1000KM) with it targeting between 16.5 and 17.

Fule consumption wasnt bad, got about 570km to a tank, not bad considering I did alot of passing

That's pretty good consumption - assuming a full 60L tank that's nearly 27 mpg. I'm interested to know more about your micro-controller gadget though - I have a PLX wideband (to replace an LC-1 that dies on me). Unfortunately the PLX units don't allow you to change the narrowband switch point in software like the Innovate LC-1 does - PLX tech support said you need to change a resistor value on the circuit board which isn't ideal.

When I did have a working LC-1 I did play with the switch point (mainly trying to get my emissions down for MOT time). I discovered that while I could move the idle lambda point slightly after a certain point further change had no effect. I wasn't sure if the ecu doesn't have some code that looks at the O2 trim levels to check if they start getting too far from the ideal and then limit them? Has anybody else noted similar?

[paulg23]

I can adjust my narrowband switch point from 14:1 to 17:1. the ECU seems to handle this OK. Its a PFL Legnum so I assume it has a 7201 in it.

[Nutter_John]

Having seen paul's gadget I was very impressed with it

[lateshow]

Having seen paul's gadget I was very impressed with it

You're referring to his car, right?


When Low Fuel trim hits ~5% or -5% it is maxxed out and at that point ecu cannot give more or less fuel in closed loop mode. We discovered this as someone accidentally used wideband signal for ecu-> result too big voltage-> ecu sees that its always too rich-> Fuel trim goes to maximum negative value and mixture is all over the place.

I've noticed that my car's exhaust fumes are really smelly now and im doing only 15.1 at idle. One fact is that catalytic converter sits at my storage now. I think that targetting to 16-17 is dangerous. I'm alreaydy worried about mine when it goes to 16 when slowing down. And the car feels maybe a little bit more sluggish than it used to when not doing full boost. It seems that going from closed loop to open loop creates a certain effect as the mixture suddenly becomes richer. Like when you accelerate a bit first it uses closed loop and then it goes quite lean 13.5-14 with little boost (as stock). Now it hits almost instantly 13-> 12. Bloody hell, have to get miself an innovate.

[paulg23]

I assume the ecu can only change the fuel trim when in closed loop. Does it keep and use this trim figure for open loop? I assume it doesn't.

[phosty]

Paul or Taylor - can you elaborate on your respective 'gadgets'? Are they simple/cheap enough to build?

[paulg23]

Paul or Taylor - can you elaborate on your respective 'gadgets'? Are they simple/cheap enough to build?

I'll put some pics of mine up tomorrow. It uses a PIC microcontroller and an LCD display. Reasonably simple circuit.

[Nutter_John]

you are under selling it Paul , look real good (well once din'd up )

[paulg23]

you are under selling it Paul , look real good (well once din'd up )

Thanks for that John. I'll put details up tomorrow and some pictures and info regarding other things it can be made to do.

[lateshow]

I'll put some pics of mine up tomorrow. It uses a PIC microcontroller and an LCD display. Reasonably simple circuit.

Im interested too as i only have the PLX. Yes, fuel trim_LOW isn't used in open loop mode.

[paulg23]

This is it so far. Pulled apart an old car radio to use as the chassis. At present it displays the contents of the LPG tank and the AFR ratio. The green button switches between petrol and LPG, the control on the left sets the closed loop AFR and the switch lets me choose between AFR, boost pressure or MPH for the main display. I will be adding a performance monitor to it soon, a sort of cut down GTech device to measure acceleration.

It uses a OEM6 lambda controller from Tech Edge to get the lambda which is then converted to AFR.

The closed loop AFR adjustment is limited at the moment by the software but could be set anywhere the lambda sensor can read. (7.0:1 to about 50:1 but I've limited it to somewhere sensible).

[lateshow]

Paul, Start producing these items ? What about adding average fuel consumption there. I'd be willing to pay quite a lot D:

[Nutter_John]

Exactly what I said to Paul
We even spoke about it doing boost control as well