No "check engine light" with headers!!!

Hold on guys, you gotta know me a little. This is grassroots tuning here, I wish I had the resources and the time to actually tune a DME with a a laptop, but I don't. I do however have a knack for reverse engineering things, when you want the DME to do something for you go to it source of input. In this case I am making the mixture leaner because I am running a 4Bar fuel pressure regulator to get my open-loop AFR down to 13:1 (they were at 13.6:1 after I installed my Schrick cams). This caused my closed loop mixture to go rich and the DME would lean it out my fuel adaptations, so be letting the motor run a little richer and not see it the DME stopped pulling fuel out and let me adaptations mellow out a little. Does this make sense?

I am not talking a radical change here, and I don't recommend radical changes. I am running down the freeway in closed-loop at about 14.2:1 AFR when the desired AFR for emissions is 14.7:1. A little fact is that for N/A motor the arguable AFR for the most power is around 13:1 AFR. Does this lower fuel mileage? Yes, a little maybe 1 MPG. Did this improve throttle response and increases in power on the butt-dyno, yes. But you can change it by just plugging in the laptop and hitting the "Factory Default" button and the voltage curve goes back to reality.

As for the post-cat O2 voltage curve, on the LM Programmer I use .650V from 8:1 up to 20:1AFR and the I run it down to .025V at 22:1AFR, but you need to make sure to go into the advanced menu and put the max 1/3 second delay on the post-cat O2 sensors signals. This will give you that lag time to show a good oxygen saturation in the catalytic converter and still give you the lean signal so the DME see's that everything is legit. This is exactly what I am trying to tell people about the simulators that just make the flat .650V signal, this might work on some simpler ECU's but not ours. Our DME needs to see a certain amount of lag time after you let off the gas pedal and go into fuel-cut upon deceleration to see the rear O2 sensor go lean. I have yet to see simulator that does this.

^ I wasn't trying to knock your approach. You definitely seem to know what you're doing and why you're doing it. I was merely trying to emphasize that this level of fiddling requires more expertise than the average DIY'er around here typically has - before someone does decide to get a little too radical.

Originally Posted by F1004fun

...

As for the post-cat O2 voltage curve, on the LM Programmer I use .650V from 8:1 up to 20:1AFR and the I run it down to .025V at 22:1AFR, but you need to make sure to go into the advanced menu and put the max 1/3 second delay on the post-cat O2 sensors signals. This will give you that lag time to show a good oxygen saturation in the catalytic converter and still give you the lean signal so the DME see's that everything is legit. This is exactly what I am trying to tell people about the simulators that just make the flat .650V signal, this might work on some simpler ECU's but not ours. Our DME needs to see a certain amount of lag time after you let off the gas pedal and go into fuel-cut upon deceleration to see the rear O2 sensor go lean. I have yet to see simulator that does this.

Thanks for the updated values. I appreciate it. Are 2 LC-1's needed or will 1 be enough for no CEL?

Thanks, John

Originally Posted by johntrhodes81

Thanks for the updated values. I appreciate it. Are 2 LC-1's needed or will 1 be enough for no CEL?

Thanks, John

1 will be enough for no CEL

Originally Posted by johntrhodes81

Thanks for the updated values. I appreciate it. Are 2 LC-1's needed or will 1 be enough for no CEL?

Thanks, John

He is using one LC-1 pre-cat to get his AFRs where he wants them, and one LC-1 post-cat to eliminate the cat efficiency CEL. So, one LC-1 can service both post-cat sensors.

Originally Posted by lkstaack

He is using one LC-1 pre-cat to get his AFRs where he wants them, and one LC-1 post-cat to eliminate the cat efficiency CEL. So, one LC-1 can service both post-cat sensors.

Well, close. In sticking with German wiring tradition, so one LC-1 is Bank1 pre-cat and post-cat and the other is Bank2 pre and post. BMW considers Cyl.1-3 as Bank1 and Cyl4-6 as Bank2. And yes I used to run one LC-1 as just my post-cat signal and it worked just fine.

Originally Posted by F1004fun

I used my old connectors from the old post-cat O2 sensors, installed a 50ohm 10watt resistor in each of two sets of white wires, these are the O2 heater ciruit wires.

For the signal and ground wires it gets tricky. So we should have two wires left over at each of your O2 sensor connections, now sensor side wiring changes so reference the engine harness side for this. Bring the two wires together that connect to the yellow wire, and wire in about 3' of small yellow wire this is the Analog1 output from the controller. Next bring together the two wires that connect to the black wire, again 3' of small black wire, this is the signal ground. Bring this signal ground the yellow wire and all the associated LC-1 wires in a nice loom into the e-box, you'll even find a grommet you can use.

Once in the e-box lift the DME and the bracket that it's held into up and expose the chunk of red-white and brown wires underneath. Connect the sensor ground wire and the white and blue LC-1 ground wires to the splice of brown grounds under the DME, next connect the LC-1's red wire into the splice of red-white yellow dotted wires. Connect the yellow wires together.

Is this how you wired the LC-1 into your post-cat O2 sensors?

Originally Posted by lkstaack

Is this how you wired the LC-1 into your post-cat O2 sensors?

Yes, thats pretty much it, but you should tie all those grounds in with a ground wire that goes to the main ground lug behind to e-box, this will keep all the signals clean and properly referenced with the DME.

thanks for your hardwork and information F1004fun im having the same issue on not be able to pass due to readiness codes not being set

i just have 1 question with the lc-1 will i still need my 02 simulator hooked up?(im running electric and anti-fouler method)

and thanks lkstaack for the diagram it helped put it all together visually

Originally Posted by DarkJoker

thanks for your hardwork and information F1004fun im having the same issue on not be able to pass due to readiness codes not being set

i just have 1 question with the lc-1 will i still need my 02 simulator hooked up?(im running electric and anti-fouler method)

and thanks lkstaack for the diagram it helped put it all together visually

Nope, you don't need post-cat O2 sensors using the LC-1. The post-cat cables running from on top of the valve cover will go to the LC-1 and common DME ground. The sensor heater wires will be connected together with the resister between them.

so you take out the secondary 02's completely and just use the wideband in 1 bung and plug the other?

Is it possible to have the exact link to buy the O2 simulator?

http://www.o2simulator.com/index.php...products_id=10

Or this:

http://www.o2simulator.com/index.php...&products_id=9


Could be the assembly diagram right? Simulators start in place of the downstream oxygen sensors ?
I ask these questions because I'm going to mount my header next Friday

Originally Posted by DarkJoker

so you take out the secondary 02's completely and just use the wideband in 1 bung and plug the other?

No. You keep the pre-cat sensors in without modification. You remove both post-cat sensors and cap (or keep 'em in but don't hook anything to them).

The LC-1 will provide your ECU with the signals it wants to stay happy as long as you program it to do so (like F1004fun did). Remember, the post-cat sensors are not needed for the tune; its just there to ensure your cat is working properly.

Edit: the LC-1 wideband isn't needed to defeat the cat CEL, but can be used downstream for a AFR gauge.

Originally Posted by lostheaven93

Is it possible to have the exact link to buy the O2 simulator?

http://www.o2simulator.com/index.php...products_id=10

Or this:

http://www.o2simulator.com/index.php...&products_id=9


Could be the assembly diagram right? Simulators start in place of the downstream oxygen sensors ?
I ask these questions because I'm going to mount my header next Friday

You're in the wrong thread for O2 simulators. This thread is for defeating cat CELs using a LC-1 in lieu of O2 sensors. It is more expensive, but works 100% of the time; unlike most people's experiences with O2 sims.

its cheaper to take the light out behind the the check engine sign

Originally Posted by lkstaack

You're in the wrong thread for O2 simulators. This thread is for defeating cat CELs using a LC-1 in lieu of O2 sensors. It is more expensive, but works 100% of the time; unlike most people's experiences with O2 sims.

Give me the link to buy the LC-1 please.

Originally Posted by lostheaven93

Give me the link to buy the LC-1 please.

Just Google "Innovate LC-1".

What is this "Google" that you speak of? Surely it's some new advancement in technology.

Originally Posted by TxZHP04

Just Google "Innovate LC-1".

And you still wouldn't pass inspection in most states. Neat comment, though.

Originally Posted by MaggioM

its cheaper to take the light out behind the the check engine sign

Originally Posted by lostheaven93

Give me the link to buy the LC-1 please.

I just picked one up from summit yesterday. They had it priced for $250 with the analog gauge.