 » Site Navigation | | | | » Recent Threads | | | |  |  |  | |  11-18-2008, 02:37 PM | | | Senior Member Join Date: Dec 2007 Location: Gulfport, Florida Posts: 3,208 |  Air Pump Simulator DIY for $12.45
I have completed my final version of my air pump simulator and it passed the testing this morning with no error codes. All parts from Radio Shack and total cost $12.45. No more $150-$200 to buy these online. I will post the complete DIY this evening when I get home from work. Here's a picture of... |  |  | By vishus on 01-30-2011, 11:07 AM |
Quote: Originally Posted by mpire  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 | | | By mpire on 01-30-2011, 03:16 PM |
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. | | | By vishus on 01-30-2011, 07:25 PM |
Quote: Originally Posted by mpire 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? | | | By mpire on 01-30-2011, 10:00 PM |
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. | | | By JP422 on 01-31-2011, 06:31 PM |
Quote: Originally Posted by xxxJohnBoyxxx 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 | 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. | | | | |
Quote: Originally Posted by mpire 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. | 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 | | | | |
Quote: Originally Posted by JP422 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. | 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 | | | | |
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 Quote: Originally Posted by xxxJohnBoyxxx 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 | | | | | |
Quote: Originally Posted by pdxmotorhead 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 | | | | |
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! | | Last edited by John Firestone; 09-11-2011 at 08:53 PM.. | | |
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 | | Last edited by xxxJohnBoyxxx; 09-11-2011 at 10:50 PM.. | | |
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 :/ | | Last edited by covert24; 09-12-2011 at 02:41 AM.. | | |
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