How to: Default Overdrive OFF modification

[Mbrooks420]

I would think this could easily be accomplished with just a pair of relays and a switch.

 

[CDW6212R]

I would think this could easily be accomplished with just a pair of relays and a switch.

Yeah, some kind of delay relay to trigger the OD switch circuit, and a switch to select that relay function or not. It's annoying right now, but not a huge issue. I've got the gas pedal bracket(spot weld) cracking right now, and have to fix that quickly.

 

[Cobraguy]

That's exactly what a TR7 is...a programmable relay. You can't beat it for price and functionality. And it's one helluva lot cheaper than a custom tune. Another alternative is a Baumann controller for the 4R70W. Again...one heck of a lot more money, but a lot of options there. I have one on my 68 Torino and can't wait to finish the car so I can play with that.

 

[gmanpaint]

@Cobraguy ... A little off topic here, (and a bit newbish to this stuff ), but kind of related. Apologies in advance.

Is there any way to tell, if there is a good circuit to the ECM, from the OD button harness at the dash side connector?

I have no OD control after an engine/harness swap, and it is not able to turn off. Continuity checks out on the shifter button. Button is not physically broken, and in good shape.

I don't know if the harness is bad, a break in the circuit, or whats up. Wondering if the TR7 or a SCT tuner, or a plain old meter, would help any with this.

 

[Cobraguy]

My first thought when I read this is did you use a harness, etc from a manual trans car?

Do you have a copy of the factory wiring diagram manual? That would give you the pinouts for not only the wiring circuit, but the connectors as well. You would be able to check your signal right at the ECM that way. Remember...when testing computer circuits, be sure and use a digital meter. An analog meter can and will damage the low voltage, delicate circuits.

I have some factory manuals that are still packed away. If you give me your year and model, I'll see if I can find one that fits.

 

[gmanpaint]

Thank you kind sir!! Been racking my head on this issue for 10 months now.

I do not have a pinout showing the ECM, or the connectors. That would be great to get those, to help figure this out.

It's a 98 5.0L Auto. Do you need the ECM serial #?

Here is the kicker. The engine swap was done to a 95. I didn't do the work, it was done by a couple of people moonlighting for extra cash. Hard to say what was done, as there is no communication with them. I am thinking they just spliced into the 95's dash harness, instead of replacing it with the 98's. It might be an issue at the bulkhead connector, with the circuits not matching. I think that pinout diagram for the bulkhead for both years would show if there is a cross wired circuit for the Overdrive. Knowing the OD button is a momentary switch, the dash side OD connector was jumped, and it didn't trigger the OD light to come on.

 

[410Fortune]

Its okay no matter how they got that 95 running with the 98 engine, it is super easy to wire in your OD off button like factory.
There is one wire from the PCM that goes to the OD off button, the other wire is hot in run (as cobraguy pointed out)
Then its just a single wire from the PCM to your OD off light in the dash
I can find the correct wiring info and post it up.

The first thing I do in ANY OF my Fords is turn off the OD when I get in. I want to control when it shifts to OD myself
In my BII with big tires the trans will shift into OD at like 45 mph or less, causing lurching.... so I do it manually, I always wait until I am doing about 60 before I allow OD
This is a GREAT MOD!!
My 1988 uses a 96 Mustang floor shifter, my OD off button is on the side of my floor shifter handle...I would LOVE to have the OD off as the default setting!!!
Thanks to Cobraguy I can!!
A programmable relay, EXCELLENT!!
FYI Baumman engineering is now USShift.....

 

[jah81592]

That's exactly what a TR7 is...a programmable relay. You can't beat it for price and functionality. And it's one helluva lot cheaper than a custom tune. Another alternative is a Baumann controller for the 4R70W. Again...one heck of a lot more money, but a lot of options there. I have one on my 68 Torino and can't wait to finish the car so I can play with that.

The reason I mentioned a tune is because most of the Gen 2 guys have a programmer and most have a tune. Not a major issue since everything has already been purchased. Most people who have tunes could talk to their tuner and they would probably help out with that. Who wants a bunch of wiring and relay BS that can be done with the on board computer?

 

[Mbrooks420]

Surely no more than 5% of 2nd gen owners on the board have a tune. If you’ve done any amount of mods to support needing a tune this amount of wiring is nothing, comparatively.