ORM Mod circuit

dgeist · **Posted:** Wed Apr 04, 2007 10:38 am

So, since 29 pages is a lot to read to get details on the ORM, I decided to make a thread just for automated systems to do the mod on-the-fly.

My first attempt is the digital logic necessary to leave the MAF operation normal when the transmission is in park, then cut power to the 5v supply lead when the shifter is in any other gear. Here's the TRS (transmission range sensor) states by gear:

And this is the basic logic design:

Since all the sensors and operating computer goodies seem to use typical 5v logic, no automotive capacitors would be necessary. If there was a good way to tap the pinouts on the TCM connector and put a small harness inline at the MAF plug, then 3 wires from the TCM and 3 from the MAF extension harness would be all that's needed. The circuit would be powered off the 5v power and ground line going to the MAF from the ECM. That way, all current would be limited to what supplies the MAF, nothing in the TCM is messed with other than tapping the pins other than a 5v logical input to the system.

There's definitely a possibility of inserting a bypass (normal operation) toggle in there (either electrically or into the logic) for when you're on-road and getting your emissions done, etc. That's not in there now, though.

I'd love suggestions on ways to safely tap the pins without modifying the factory plugs/harnesses. Other than that, this is just a little breadboarding with a ttl logic chip and a bit of solder

Dan

DnA Diesel · **Posted:** Wed Apr 04, 2007 1:51 pm

I would think the way to do this would be to replicate the plugs with an inserted length of cable leading from the MAF and TCM to your module...trouble isgetting the plugs as they are normally part of a much more expensive harness...maybe there's some kind of standardization to the plugs...maybe AMP or PAIN or other elec co.s have something that will work. That way, worse case, just detach the inserted mod hanress and you're back to stock.

Good idea, Dan!

Cheers,
Duey

stevesmith7 · **Posted:** Wed Apr 04, 2007 2:55 pm

Dan,
Forgive me as I'm a retired logic designer and don't get many chances to do this anymore.

Some simplifications:
How about just using pin 42 to control? Disabled when in any drive mode.
How much current does the sensor draw? Can a gate supply it?
How about a simple NPN transistor with the collector connected to 85 of the ECM, emitter goes to the MAP pin 6, base driven by pin 42 signal.
Is pin 42 when open pulled up to 5V? If so pullup will limit base current. If not need a pullup to +5V. If switched to +5V need series R in base.

Just some thoughts. I ran with the MAP disconnected the other day and the EVIC barely went below 30mpg even in town.

Steve

Special Agent · **Posted:** Wed Apr 04, 2007 10:41 pm

Sorry I'm a little slow:

But is this a sort of blueprint for a circuit board that could be built and plugged in to kill the evil EGR?

If so, where can I send the money?

Wilmo · **Posted:** Thu Apr 05, 2007 12:39 am

Have you guys seen this post? Might make what you are trying to do unnecessary.....

http://www.lostjeeps.com/forum/phpBB3/vie ... 328#189328

apologies for hijacking the thread

dgeist · **Posted:** Thu Apr 05, 2007 1:57 pm

DnA Diesel wrote:

I would think the way to do this would be to replicate the plugs with an inserted length of cable leading from the MAF and TCM to your module...trouble isgetting the plugs as they are normally part of a much more expensive harness...maybe there's some kind of standardization to the plugs...maybe AMP or PAIN or other elec co.s have something that will work. That way, worse case, just detach the inserted mod hanress and you're back to stock.

Yep, AMP has the MAF plug and it's also shared by newer ford MAF systems (as reported in the ORM thread). I know that AMP (tyco) will send sample packages, but the sensor side of the plug is not made by them. They just provide engineering specs. I have a feeling getting a MAF extension for one of those newer ford models might be easier. I haven't looked into the TCM plug yet.

stevesmith7 wrote:

Dan,
Forgive me as I'm a retired logic designer and don't get many chances to do this anymore.
Some simplifications:
How about just using pin 42 to control? Disabled when in any drive mode.
How much current does the sensor draw? Can a gate supply it?
How about a simple NPN transistor with the collector connected to 85 of the ECM, emitter goes to the MAP pin 6, base driven by pin 42 signal.
Is pin 42 when open pulled up to 5V? If so pullup will limit base current. If not need a pullup to +5V. If switched to +5V need series R in base.

Steve, I switched majors in school after one digital logic course. Software is more my strongsuit, but your suggestions may be valid. First, logical trigger would need to be all 3 pins. If you look in the "truth table" above, when the shifter is in park is the only time all 3 of those leads are logical high (hence the 3-way AND). I don't know the current draw, but I'm sure more durable (not educational TTL chips) are the way to go anyway. The diagram was just my attempt at the logic involved.

Edit: Yes, it took a week for me to notice that you're absolutelly right on ping 42 since most folks don't spend much time in reverse.... Ultimately, I'd still like it only in park, but that's just me being anal.

Special Agent wrote:

Sorry I'm a little slow:
But is this a sort of blueprint for a circuit board that could be built and plugged in to kill the evil EGR?
If so, where can I send the money?

SA, that's basically the idea. The logic above kills power to the maf sensor when the tranny comes out of park. You'll still get error codes, but it should prevend the CEL from coming on. I don't even have the parts to build it, but I don't know that I'll make a commercial venture out of it. My better half would probably like me to not have YAP (yet another project).

Dan

dgeist · **Posted:** Thu Apr 05, 2007 2:14 pm

Wilmo wrote:

Have you guys seen this post? Might make what you are trying to do unnecessary.....

http://www.lostjeeps.com/forum/phpBB3/vie ... 328#189328

apologies for hijacking the thread

I noticed that one but just didn't respond. Depending on location, emissions in the states can be brutal and it's actually against federal law to bypass certain emissions systems. I'm not saying I don't ever break the law, but the originally thinking was to make a solution that could easily be undone/shut off as needed (like when you go back on the road...). Also I'd think there's arguable benefit to using heated gasses on startup to help bring temp up a little faster.

Ultimately, there's more than one way to skin a cat, and I like my cat skinned electronically with a toggle switch

I might feel different if I didn't have so many miles left on my warranty.

Sir Sam · **Posted:** Thu Apr 05, 2007 6:15 pm

dgeist wrote:

Wilmo wrote:

Have you guys seen this post? Might make what you are trying to do unnecessary.....

http://www.lostjeeps.com/forum/phpBB3/vie ... 328#189328

apologies for hijacking the thread

I noticed that one but just didn't respond. Depending on location, emissions in the states can be brutal and it's actually against federal law to bypass certain emissions systems. I'm not saying I don't ever break the law, but the originally thinking was to make a solution that could easily be undone/shut off as needed (like when you go back on the road...). Also I'd think there's arguable benefit to using heated gasses on startup to help bring temp up a little faster.

Ultimately, there's more than one way to skin a cat, and I like my cat skinned electronically with a toggle switch

I might feel different if I didn't have so many miles left on my warranty.

Some of us without warranties wont care

Heck im ready to start cutting chit up already!

dgeist · **Posted:** Fri Apr 06, 2007 9:52 am

Sir Sam wrote:

dgeist wrote:

Ultimately, there's more than one way to skin a cat, and I like my cat skinned electronically with a toggle switch

I might feel different if I didn't have so many miles left on my warranty.

Some of us without warranties wont care

Heck im ready to start cutting chit up already!

Sam, your job is easy, just splice in a decent automotive-rated toggle switch and run it into the cab through the firewall somwhere to switch on/off power to the MAF. not elegant, but cheap and fast

Tinman · **Joined:** Mon Apr 10, 2006 10:45 am **Posts:** 308

Which wire needs to be interrupted?? I drove my wife's libby last night and did the unplug- after- start -up and plug- in- before shut down twice. No CEL and the thing ran great. This stupid EGR has got to go. I'm thinking of a switch on the gear shift to open the circuit when out of park.

Sir Sam · **Posted:** Fri Apr 06, 2007 4:52 pm

dgeist wrote:

Sir Sam wrote:

dgeist wrote:

Ultimately, there's more than one way to skin a cat, and I like my cat skinned electronically with a toggle switch

I might feel different if I didn't have so many miles left on my warranty.

Some of us without warranties wont care

Heck im ready to start cutting chit up already!

Sam, your job is easy, just splice in a decent automotive-rated toggle switch and run it into the cab through the firewall somwhere to switch on/off power to the MAF. not elegant, but cheap and fast

Yes, though like you guys I like the idea of using a ford harness and hacking that up, not reason to mess up stock stuff if we dont have to right?

dgeist · **Posted:** Sat Apr 07, 2007 3:04 pm

Tinman wrote:

Which wire needs to be interrupted?? I drove my wife's libby last night and did the unplug- after- start -up and plug- in- before shut down twice. No CEL and the thing ran great. This stupid EGR has got to go. I'm thinking of a switch on the gear shift to open the circuit when out of park.

Here's the MAF pinouts:

So, probably disconnecting pin 5 or 6 would accomplish the goal.
... and a switch actuated BY the shifter was what I was working towards (although at this point I'd be happy with a toggle switch under the dash). The biggest thing really is getting intermediate harness plugs to be able to "break-out" the pins and manipulate them without hacking up the factory wiring.

Dan

MrWinkey · **Joined:** Tue Apr 18, 2006 3:16 pm **Posts:** 37

I'm ordering the connectors right now. Then I'll see if I can tap into the TCM module to use as a signal to flip the 5v on and off. Should be simple with a lil relay.

curtis · **Posted:** Sat Apr 07, 2007 7:37 pm

Where are you getting the connectors from?

I'm searching for a 05 Mustang MAF extension to purchase.

dgeist · **Posted:** Sun Apr 08, 2007 4:06 pm

MrWinkey wrote:

I'm ordering the connectors right now. Then I'll see if I can tap into the TCM module to use as a signal to flip the 5v on and off. Should be simple with a lil relay.

I've never used anything other than 12v relays in automotive apps. If you're familiar with 5v automotive ones, then the logi circuit above can be replicated easily with a chained relay bank (3 or 4 of them, I think). It would also lend it self easier to a bypass switch.

Tinman · **Joined:** Mon Apr 10, 2006 10:45 am **Posts:** 308

My 01 Cummins has a aftermarket transmission that has a valve body for second gear lock up. The factory trans wasn't able to to the second gear lock up, so the trans vender, DTT, came up with a swtich that is bolted to the bell housing of the trans and is positioned in such a way that the shift linkage going into the valve body grounds out the switch when the shifter is pulled into second gear. This turns on the DTT transmission controller an I have second gear TC lock up. I'm thinking of a switch like this that would ground out the #5 pin/wire in Park and is an open circuit in gear. If there is a place to mount such a swtich, (either in the linkage or center console) this should do the trick. Make the connection to the MAF ground in the loom and it could be reconnected and hidden if needed for warrenty or emmisions. I'll look around on the libby when I get chance and see if this particular switch has a place to be located. If so, I'll give DTT a call and see if I can just get a swtich from them.

techTim · **Posted:** Mon Apr 09, 2007 2:13 pm

thanks to all you big brained sparky types, I am seriously thinking of killing the F_ing EGR even with 85 K left on the factory warranty. I'm going on an eight hundred mile round trip this weekend, and plan on doing one way with the ORM and the other without to calculate the mileage / driving difference. Will post back Monday next.

Keep up the good work out there. can't wait to have a bypass harness for ease of switching the ORM off and on.

GoghUA · **Posted:** Mon Apr 09, 2007 10:25 pm

I haven't had the time to read the entire 29 pages of the ORM thread, but what I have read certainly gets me interested.

My other car is a 2000 Pontiac Grand Prix GTP with a supercharged 3.8 v6, which brings me to my point...
A company named Easy Performance has a module called the EGR D-lete that "disables or allows complete removal of the EGR system from GM OBD-II vehicles without setting any check engine lights." Follow the link for more details on what it does and how it works. Also, be sure to look at their install instructions as they provide some more detail on how this works.

All of their products are GM specific, but perhaps someone here can either a) get a better idea on how to implement this for our vehicles by reading the details they provide or b) contact Easy Performance and see if they would be willing to provide any assistance (knowledge or engineering wise) on reaching a solution.

Hope this was helpful.

CHessMaster · **Posted:** Tue Apr 10, 2007 12:45 am

Here's some more fuel to the fire.

Hooked up the MAF sensor ground wire to the Park/Neutral switch (circuit #T41), This effectively turned the MAF sensor on only in the Park and Neutral positions of the shifter. The MIL came on after the 2nd trip. I then hooked the MAF ground wire up to transmission circuit #T42, which then turned the MAF sensor off only in the shifters forward gear positions. The MIL still came on after the 2nd trip.

In summary, the MAF was on at start-up and before shut-down, but the light still came on after 2 drive cycles.

I verified the MAF worked as stated by using a scan tool.

Any comments on this?

BlackLibertyCRD · **Posted:** Tue Apr 10, 2007 8:37 am

CHessMaster wrote:

Here's some more fuel to the fire.

Hooked up the MAF sensor ground wire to the Park/Neutral switch (circuit #T41), This effectively turned the MAF sensor on only in the Park and Neutral positions of the shifter. The MIL came on after the 2nd trip. I then hooked the MAF ground wire up to transmission circuit #T42, which then turned the MAF sensor off only in the shifters forward gear positions. The MIL still came on after the 2nd trip.

In summary, the MAF was on at start-up and before shut-down, but the light still came on after 2 drive cycles.

I verified the MAF worked as stated by using a scan tool.

Any comments on this?

Yeah! That means to just unplug the MAF for your continious off road use. Only plug it in and clear codes when taking to dealer and state inspection.

ORM Mod circuit

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