John,

I have built this simulator for an E36 M3 and am having a couple of issues. I was hoping you might have some insight. I made the dual version for both my oxygen sensors. I wired it into my front two oxygen sensors (pre cat). Are these the correct sensors?

In addition, it seems to work fine during warm up unless I "get on it" a little. I am not saying beating it but if I am slightly aggressive, it will set the cel. Now if I grandpa driver it, no cel. Any thoughts on this?

I set the reference voltage to .2v and everything seemed to work for 2 cool days driving like a grandpa but on the third after goosing it a little, it threw the cel. Thoughts?

needs to be on the post cats!
pre cat O2's help balance the air/fuel ratio by measuring how much un-burned fuel is in the exhaust gas.

dantesboyz,

Have you installed one of these on your car?

Wrong this will not work. The DME reads upsteam O2's for SAP verification. The DME looks for a lean condition when the SAP is on since it's pumping fresh air in the exhaust. This is the whole reason this simulator works...It fools the DME into thinking the SAP pump is working on the front O2's. This works on all cars with a SAP.

The until only turns on during SAP. When SAP is off the simulator goes into pass-through mode and all your O2 reading or Air/Fuel ratios pass right through the Simulator to the DME untouched by the simulator. Look at the design and you will figure it out if you know anything about electronics

Hope this clears it up. I think there are at least 50 on these on cars with no errors. INSTALL on upstream O2's or suffer an SAP error...

John Smith

Hello Thanks so much for making this DIY
I would also like to know if this will work on a 03 bmw z4 2.5i and will it pass emissions?

As Im Having secondary air pump CEL as well

Yes it will work. The design is not for passing emissions however it will 100% of the time. The simulator sends the SAP operation checks to the DME and it can't tell if the pump is not working or removed

John - I am trying to install a 96 M44 into a 98 318ti and I am having trouble dealing with all the smog stuff in the 98 harness and such. I do not have the headers with the exhaust valve and I don't have the air pump. I was thinking that this simulator would solve most of my problems, but I still have other questions as well. Could you email me so I have a way of contacting you? Thanks!

I want it for M44, what's the difference, if any? Thanks!

Look up single bank simulator in the knowledge base.The M44 one uses the same therory but only one relay and one pot.

I just want to give a heads up that these parts are not compatible with the pcb board made by bluesteel.

they do not fit properly. therefore it's better to use the parts he suggests.

I made that mistake.

Single pot schematic
 

Since no one had a circuit diagram/schematic, I drew one up.

http://img.photobucket.com/albums/v3...umpsim-001.jpg

I gathered everything on Neil's shopping list, but I haven't assembled it yet.
If anyone does, take some pics and post them up. I'll do the same.

Thanks for this! would you say the signal has to be set to 200mv for all cars or do you think it could vary?

Im doing this for a z4. also I don't see any tutorials for my car and have no idea how to locate those cables.

I used all data which contains same as http://wds.spaghetticoder.org/ it explains how the circuit functions and the cables to look for. But the schematic only shows one cable going from the dme to the o2 sensors.


here is mine

http://img268.imageshack.us/img268/6724/pcbr.jpg

Is anyone willing to make me one of these for an m44? I suck at soldering and reading wiring diagnostics. I am willing to pay you for your time too!

I can make a 6 cilinder version..if you don't mind the extra cables.

or 4 I guess it's same thing

The 200mv signal is simulating a lean condition to the DME (computer) as reported by the O2 sensor. It is most likely the same for all cars.

You only need to identify the wires that run from each of your pre-cat O2 sensors to your DME. (one wire for each O2 sensor.) I'll see if I can find a link to your electrical schematics when I get home. E85 or E89?

If an electrical schematic isn't available, you can just find the pre-cat 02 sensors in your car, then identify the wires leaving them by color. My personal preference is to locate the sim in the compartment with the DME to keep it out of the elements. To do that, you want to locate and cut the two O2 wires to the DME a few inches from the connector to the DME. Bring the existing secondary air pump wiring back into that compartment as well.