How to get e4od 7.3 to downshift more often?

[85_305]

Because the PCM is programmed for the gear ratio you have in your truck which would either be 3.55:1 OR 4.10:1. Once you change tire size, either bigger or smaller, it changes what the computer expects to see from the VSS/PSOM. This in turn will change the shift parameters that the computer sends to the transmission during its commands. Basically the tone ring in the rear will either spin faster or slower than it would with the "correct" size tires on the vehicle. This in turn basically confuses the computer. It will try to compensate but will not be correct until you correct the faults to the best of your ability such as changing the code for the PSOM.

interesting! yes I have 4.10's, but I'm sure w/ the 35's bring to to like 3.80's or 3.70's or something like that.

So changing the code in the PSOM will probably fix most if not all of this weird shift issue then?

 

[Bobby@cp]

Recalibrating the speedo will fix some issues but to get it as close to stock as you can you would be better off with 4.10s

Sent from the doughnut shop

 

[85_305]

My truck has 4.10's:ford:

 

[SPEEDDEMON31176]

Yep recalibrate the PSOM in the speedo and you should see most if not all of your shifting issues go away. No guarantee it will be the fix all but it will definitely help.

 

[85_305]

Yep recalibrate the PSOM in the speedo and you should see most if not all of your shifting issues go away. No guarantee it will be the fix all but it will definitely help.

Excellent! I was hoping it was a tunes thing, but really didn't think 1-3mph down low and 5-10mph up top would make that big of a diff.


Although, perhaps this is why my truck wont downshift from 4th when I hit it from a highway roll half the time :doh:

 

[Bobby@cp]

Yeah, I seen it after I posted....

Sent from the doughnut shop

 

[85_305]

Ah well. At least I have some direction to this. Gonna get this reprogrammed and see how everything works.

 

[Charles]

Lol!!!!!!!!!!!!!

But 1st gear lasts until what...35-40mph? Even a few mph off should still force a downshift @20mph.

You're implying that the downshift point isn't even close, as in the speedo being a few mph off wouldn't possibly be the issue, however your own actual account showed this:

Then other times I catch it just right, and it will catch 1st and peg out real nicely.

Showing us that it's actually sooooooooooooooo close that sometimes the mph/tps combo does in fact end up with the PCM calling for a downshift.


It would seem that the difference between getting your downshift and not getting it depends on something very close to right. Else you wouldn't ever get the downshift when you wanted...


I didn't read the rest, so if the issue was resolved, so be it. If it's not your speedo, then simply have Jonathan bump the damn downshift point. He can have it stay in first gear till redline no matter what TPS setting your at with about 5 seconds of work if that's what makes you happy.

 

[85_305]

You're implying that the downshift point isn't even close, as in the speedo being a few mph off wouldn't possibly be the issue, however your own actual account showed this:

Showing us that it's actually sooooooooooooooo close that sometimes the mph/tps combo does in fact end up with the PCM calling for a downshift.

It would seem that the difference between getting your downshift and not getting it depends on something very close to right. Else you wouldn't ever get the downshift when you wanted...

I didn't read the rest, so if the issue was resolved, so be it. If it's not your speedo, then simply have Jonathan bump the damn downshift point. He can have it stay in first gear till redline no matter what TPS setting your at with about 5 seconds of work if that's what makes you happy.

I see what you are saying. I just know that a 30mph downshift is where these trucks take off like a rocket, because it's a 2-1 downshift that puts 1st at the top of the band. And being at 20mph is a good 10mph off from that shift point, IE there shouldn't even be a HESITATION to shift at that rpm... but apparently it is the tires (or something) causing this weird issue.

If that doesn't fix it, then I'll see what the VB and TC do for shifts. And when I have my chip reburned for the larger injectors/tc/vb, I'll ask that he knock the downshift points a touch. But it seems to do it higher in the rpm's also, so hopefully this is something as stupid as the tires wreaking havoc.

 

[Charles]

I see what you are saying. I just know that a 30mph downshift is where these trucks take off like a rocket, because it's a 2-1 downshift that puts 1st at the top of the band. And being at 20mph is a good 10mph off from that shift point, IE there shouldn't even be a HESITATION to shift at that rpm... but apparently it is the tires (or something) causing this weird issue.

If that doesn't fix it, then I'll see what the VB and TC do for shifts. And when I have my chip reburned for the larger injectors/tc/vb, I'll ask that he knock the downshift points a touch. But it seems to do it higher in the rpm's also, so hopefully this is something as stupid as the tires wreaking havoc.

The programming can make it do anything short of make coleslaw just so you know. If you want it to hang first gear until 4000rpm, and then not downshift until you're lugging down at 4mph, that can be done as well.

There's no need to change any actual hardware just to get a shift point you want. If you wanted it to short shift through all gears and lug in OD by the time you reached 12mph, that could easily be arranged.

Just read your pedal voltage, and tell him at what voltage you want a downshift at _____mph in _____ gear, as well as what pedal voltage it takes to get that down shift currently. He can nail it from that.

 

[85_305]

The programming can make it do anything short of make coleslaw just so you know. If you want it to hang first gear until 4000rpm, and then not downshift until you're lugging down at 4mph, that can be done as well.

There's no need to change any actual hardware just to get a shift point you want. If you wanted it to short shift through all gears and lug in OD by the time you reached 12mph, that could easily be arranged.

Just read your pedal voltage, and tell him at what voltage you want a downshift at _____mph in _____ gear, as well as what pedal voltage it takes to get that down shift currently. He can nail it from that.

Dude your sweet (no homo)!! All it takes is TPS voltage and he can shift according to that??????????????????

Are you sure this is ALL possible on the e4od??

 

[Charles]

Dude your sweet (no homo)!! All it takes is TPS voltage and he can shift according to that??????????????????

Are you sure this is ALL possible on the e4od??

It's probably vehicle speed and Accelerator pedal position. If you tell him the voltage he can figure the pedal position, and if you tell him the mph you're reading on the speedo he will know what the PCM is seeing. The key being to provide these figures under the exact conditions you want the shift to occur under. Like, at ____mph mash the pedal until you wish it would downshift and tell him it was at ____ volts and ____mph and I wanted a downshift from 2 to 1 and it wasn't happening.

And you might just mess up and see that your TPS isn't going to full voltage but some of the time or something along those lines....

:toast:



Fwiw, my truck 100% makes all shift points based on VSS and TPS. Period. I see no reason why yours would need anything else. There could be temperature lockouts on some features for cold or hot oil perhaps. Talk to your tuner.

 

[85_305]

It's probably vehicle speed and Accelerator pedal position. If you tell him the voltage he can figure the pedal position, and if you tell him the mph you're reading on the speedo he will know what the PCM is seeing. The key being to provide these figures under the exact conditions you want the shift to occur under. Like, at ____mph mash the pedal until you wish it would downshift and tell him it was at ____ volts and ____mph and I wanted a downshift from 2 to 1 and it wasn't happening.

And you might just mess up and see that your TPS isn't going to full voltage but some of the time or something along those lines....

:toast:



Fwiw, my truck 100% makes all shift points based on VSS and TPS. Period. I see no reason why yours would need anything else. There could be temperature lockouts on some features for cold or hot oil perhaps. Talk to your tuner.

Great input! But are you referring to the e4od? Because I know they are a computer controlled tranny but are still not quite "smart" tranny's. I actually emailed beans a few days ago; I know I should probably call them. But I'm def gonna want some custom shift points after I get the new sticks.

Right now first will wrap out REAL nice, but 2nd shifts a touch short, and so does 3rd, but I think that has more to do with stock 90cc injectors and stock tranny pieces that the shifting is a bit conservative after 1st.