Find the upstream O2 sensor. Cut the signal wire and patch the Blue wire to the wire you clipped leading to the O2 and the Grey to the other end that you clipped that would lead to the DME.

When the SIM is off it will connect the clipped wire and your O2 work normally and when the SIM turns on it sends a 200mv signal to the DME tricking it so it thinks the air pump is working

John,
do you think this will work for the 6 cyl motors as well?

I think John already answered that....

My car is the 1997 BMW 328I. There are two O2 sensors. They both have the following color code: Black, Red, Yellow and White. So,
How do I know which O2 to tap into because there are two O2 sensors?
Which wire COLOR is the signal for the DME?

Bump for a great article~ :cool:

Would someone be willing to build me one of these for like $20 bucks for my S52 swap? I really don't have the time but my car will need to pass emissions.

It is hard to find someone to make one for you when you want to use it to pass emissions. These are to be used for track or off road use only, this is to protect 318ti.org for posting this DIY. If the intended use is track or off road then it might be easier to find someone to build one for you.

Also $20 will barely cover the parts for a 2-bank which you will need for a I-6. The $12 one is for the 1-bank version for the I-4.

Best, John Smith

Ah I understand, how do you make a two bank system? I guess I'll have to wait to do the delete till I rally the car, time to start looking for a secondary air pump :( $$

Sorry to spoon feed you but if you start at the beginning of the thread you will find it. It is all in this one thread. If you need any help ask or email me and I will help. People are running these on all kinds of cars: Chevys, Fords, Imports, Etc.

I was getting a lot of emails in the beginning but it has slowed down lately.

Good luck, John S

Hahah no it's cool, it was late and I wasn't paying attention, Thanks for all your help though.

Anyone who is good with these want to make me one I'll paypal you, Don't feel like spending the $200 for the AA one and not as good as some of you with wiring etc.

Let me know thanks!!

97 E36 M3 s52

$40 shipped? and a copy of my last DVD "Speed of Dark"

email me Boondocksaint@comcast.net

Well, after spending 4 hours putting this together, I now know why it costs $200. Its a serious PITA! :eek:

http://sphotos.ak.fbcdn.net/hphotos-..._8338452_n.jpghttp://sphotos.ak.fbcdn.net/hphotos-..._7067782_n.jpg

I built my air pump simulator and a DISA bypass into the same box... but I have yet to install it. Strange thing is neither my DISA nor Airpump are hooked up (removed actually)... but no CEL. The DISA throws a code, but only the PEAKE tool can find it... and the missing airpump has no code.

I do have a reflash from TT (NickG). Perhaps that is helping?

Nick G's code stops the CEL but the code is still there and can be found so your right on the DISA no CEL but still has code.

Don't worry the Air Pump will come back to haunt you give it a few runs where the DME calls for it and the O2 does not detect a lean condition and it will throw a CEL (Air Pump InOp)

Best, John S

Dude that is sweet looking. Very compact so I feel your pain. A lot of people are like "what" when I told them $75 for one. I don't make them anymore but might do a run of like 5 if I could get 5 buyers. They are a PITA to make

Good job man, you saved $188, much respect from me to you

John Smith

lol... ok, well, mine is all ready to install anyway... I'l get around to it someday. Thanks for your tips!~

-Joe

I would like some insight on how and where to wire in LEDs for various stages.

I know someone posted something along those lines.

I have an 12v LED that lights whenever its powered up.

It should only light when the unit is on or in simulation. Here is how it works...DME calls for Air Pump. Simulator goes active and removes O2 signal and inputs 200mv signal to DME telling it the exhaust is lean or it is being injected with air. The DME is happy thinking the air pump is working. DME calls for Air Pump to turn off and simulator turns off. There is no power to simulator so it is a pass through devise and you O2 signal is just passing right through it and your DME is gtting it's O2 reading like you never cut that O2 signal wire when you installed the simulator.

I hope this explains why the LED is only on a short time when you first start the car in the morning and maybe better understand how the simluator works.

I don't think there is a post for different stage LED's since there is only one stage for the Air Pump

John S

Probably so. I assume you just wired in the LED directly to the power leads from the air pump? At least thats what I did.

I am testing it on the wife's car first just to be careful.

So I am having trouble getting this to be exactly 200mv. I get a fluctuation of around 10mv.

Also there is no fuse on this thing, so I think I will need to make some modifications.

Hi mpire,
Wondering, once you've solved this issue, would you consider building and selling? I would be interested in purchasing one. I'm not so good or very patient when it comes to this type of stuff :) I was about to go pick up the stuff and try building one but from the photo's... your box looks pretty sweet! I'm totally willing to pay a fair price plus shipping expenses.
cheers

I am going to replace the pot with resistors and put a fast blow fuse in, then I will give it another try.

I am still concerned with it varying in voltage from 195-215 mv.

I am way over thinking this though.

I'm no wiz at this stuff but ya, maybe you're overthinking it lol...... maybe try a different pot. Maybe you have faulty pot's or voltage regulator? I'm sure there are better quality pot's and v regulator's than what Radio Shack is selling. For the price of a pot or voltage regulator maybe start there?

A pot is just a variable resistor.

I am complaining about a 20 mv swing here, thats almost nothing. I just like to do things thoroughly.

Well... the CEL has finally surfaced! I've been running w/ NIckG's stage2 flash and my A/F had been 14.7 @ idle... and 12.5 @ WOT... ran sweet... and even ran a track day with no problem. Then I found out I had a leak at my injecotr bases (injector adapter leaking). This caused my idle to wander a little bit sometimes, but it wasnt bad. Meanwhile NO CEL.

THEN, I got the bright idea to fix it all, so I solved the vac leaks, and now, the engine is about 0.5 richer! At cold startup, the A/f is now 14.0 (+/- 0.3) and the secondary air pump is finally called into action... only I removed mine (just be procrastinating after DASC install). I believe the CEL will be on as long as the pump is missing. I probably should pull the battery to reset the ECU's "learned" memory too.

I did make Johnboy's simulator, but I'm gonna keep it as a backup. I can definitely smell the richer exhaust fumes, and feel I can appreciate a leaner exhaust (that the air pump should provide)... even if just for cold starts.

Anyway, if the CEL really is resolved just by re-installing the pump, then my simulator may go up for sale.

Just some quick thoughts:

1. O2 sensors give a varied voltage so the voltage swing simulates actual condition better then resistors with a pegged voltage.

2. I like to have a adjustable pot since charging systems vary, DME's vary and there are too many conditions to account for, sometimes voltage needs to be cranked up or down from 200mv to make this work correctly. I have helped over 100 people build these on multiple car brands so I state this as a fact. On your car run the simulator and ensure it has eliminated any CEL then get your OHMs to be 100% on the correct resistor. Just a friendly hint encase your one of the very few that needs a pot tweak...

3. Where are you installing the fast blow fuse? I'm interested if your going on main voltage, regulated voltage or padded voltage. Obviously, do not fuse the pass through or you risk a big reliability issue.

Best, John S

Yea man I'm sorry that came back but I knew it was coming back to haunt you. It is best to run your air pump if you can. These simulators are for track cars or systems that don't have a header for air pump injection, like my turbo manifold. I just don't have the air pump connection and I needed the room under the hood for my Meth pump setup. Best of luck, John Smith

I created a PCB and posted it under the 6 cyl portion of this site. The PCB should work for the 4 cyl, just leave a few parts off.

Here is a link to the post. Enjoy

http://318ti.org/forum/showpost.php?...25&postcount=3

The ripple your seeing could be the regulator fluttering a bit, it may need a capacitor on the output to tie it down a bit? Or try ordering a new regulator, luckily they are cheap! :)

Dave

Dave I don't have a problem with my original design, it has worked for years with no issues. I'm just questioning other people that want to improve on my basic design. I believe they should start their own thread stating new and improved SAP simulator. The PCB board is super clean and I like it but be prepared to give support with your product. I give free support weekly via email and phone.

Best to all and let's improve if it's needed and will be cost effective, John S

Can John or someone knowledgable in the area check my wiring?

I apologize for the messiness... Haven't picked up a soldering iron in about 5 years...

http://t.co/DAxb4lh

http://t.co/Z8UDGWQ

I can't see anything obviously wrong with the soldering, but I haven't any experience with putting a circuit made with point-to-point wiring in a car. I've always made up a printed circuit board, or had one made up, as then I know the mechanical stresses are under control.

If you can manage the fairly modest extra effort to design one, it could be really hard to resist getting a PCB made for your next project -- they have gotten so inexpensive these days. I just ordered a board (or rather three copies of the board) for a more complicated circuit for my DRLs, that cost all of $20, including airmail postage from America to Germany. It would have been $15 with postage if I lived in the U.S.

I can't get much design data on the relays you are using, perhaps because Tyco/OEG is discontinuing them. I didn't see any decoupling capacitors for the voltage regulator. A 7805 is more tolerant and stable than most, but it could still oscillate without them at extreme temperatures.

There are lots of refinements I might try for a secondary air pump simulator, to make it smaller and more tolerant of abuse. My car, however, was built in June 1996, so I don't have a DME that needs one or that I can test it on.

Reading that back, I'm not sure I was much help!

Looks ok but I can't see all the connections. You can test it. Just hook to a battery and you should see around 200mv on the O2 to DME lead to ground. When the simulator is disconnected from batter the O2 leads should be a short or pass-through so the O2 signal is going to the DME so the DME and O2 lead should be a short.

Good luck, John S

Thanks for suggesting to just test the circuit. I meant to, but by the time I finished thinking and writing about everything else, I had forgotten the idea. I guess that's a curse of being a details guy. :(

Alright. Now. To test it, you just put the O2 and DME wire together on one lead Of the Multimeter and then the other lead of the M/M on the GND/Negative from the SAP wire and look for .200 volts? Then disconnect SAP +\- and then what should I put the M/M on to see if it's straight through? I'm sorry my brain has been taxed beyond it's limits between trying to figure out this SAP sim and INPA/Ediabas. Mostly INPA.....


Edit: I also forgot to mention how much I appreiate all the help so far from both of you. Also what kind of decoupling capacitor would you recommend me to get and which to components would you put in inline with? Im seriously considering ordering a Pre-printed board if my hack job doesn't work :/

No to test energize the sim and test the DME wire only to ground. You should have 200mv or around there. When the simulator has no power or is off the O2 and DME wire should be ohm'ed and be a dead short.

The reason is to install you cut the O2 signal wire and patch the simulator in. When the Sim is off the O2 signal is sent to the DMEsince the simulator is in pass-though and the O2 signal is sent like the wire was never cut.. When the DME calls for Air Pump the sim goes active and cut the O2 reading and sends a 200mv signal to trick the DME into thinking the air pump is in and working correctly. Hope this clears it up a little

The datasheet (728K PDF) states that an 0.33µF (or more) capacitor is required between input and ground if the regulator is an appreciable distance from the power supply filter (most likely). It also recommends an 0.1µF capacitor between the output and ground for better stability.

I've been quite happy with these guys for small, one off boards. They are a bunch of hobby robotics enthusiasts who arrange group PCB orders for their projects.

Wow I'm an idiot lol. I've read and re-read this entire thread and it didn't click until you posted that. Thank you! I will test it when I get out of work and report back with my results.



Alright well looking at radioshak they only have a 1.0uf for the input to ground and they have a .1uf for the output to ground. Would these be sufficient given there voltage is a little high or is that just the maximum voltage they can handle?

Links:

Input-Ground: http://m.radioshack.com/radioshack/p...egoryId=&path=

Output-Ground: http://m.radioshack.com/radioshack/p...egoryId=&path=


Would these be sufficient?

The 50V is the maximum rated working voltage. The ceramic capacitor may behave a little differently depending on voltage, but that won't affect its use here.

I would not put a tantalum capacitor on the voltage regulator input. They are notorious sensitive to low impedance voltage changes, and usually fail by shorting out. :(

How much trouble would it be to wire three 0.1µF ceramic capacitors in parallel?

Alright update: I feel like I wanna jab this soldering iron into my temple...


It's not working and I'm not sure why. Everything is soldered on correctly and the relays click when they are energized but no dice on the voltage deal.

I mean I get voltage from the DME wire but when I turn the pots nothing happens with the readings. And this is my second set if pots by the way. Any specific tests I could do to make sure each component (other then the relays) is working correctly? Going to try and wake up a little early this morning and see if I can make any headway before work. Maybe I can go to work happy lol. Realized today I had the +/- leads on my meter switched btw.... Yea it's been a little bit of a struggle.. Haha