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Converting From Drive by Wire Throttle to Manual Throttle

13K views 28 replies 16 participants last post by  Leadnut 
#1 ·
Has anyone ever attempted or successfully changed over to a manually operated throttle from the drive by wire throttle?
 
#2 ·
Maybe I'm speaking over my head, but my initial thought is that it really isn't possible. Well, might be possible, but a HUGE effort. And I mean GALACTIC. The ECM controls the PCM and the other controllers in the vehicle with the various CANs in the vehicle and I think they are all integrated- meaning that you've have to disable or bypass darn near every system in the vehicle. You'd have trouble codes out the wazoo, drivability would be suspect until after you resolved a slew of stuff, and then probably only get nominal results.

Back in my auto crossing days there was a thing called a Tec 3 I think that was a fuel management system that was fully programmable that might do something like this, but that was taking a less sophisticated system and making it more so, not the other way around.

Bottom line, if you wanna get away from the nannies, you'd probably need to go back to a TJ at a minimum. Now I could be wrong and there might be a system on the market, but again, think would be a monumental effort and far from plug and play.
 
#6 ·
Maybe I'm speaking over my head, but my initial thought is that it really isn't possible. Well, might be possible, but a HUGE effort.
I'm not exactly sure it would be as bad as you make it out to be... but it would require some rather specialized fabrication.

You'd leave the TPPS and TPS both in place. You'd have to find some way to allow the ECU-actuated throttle to stay in place, while allowing a static override based on the cable. Then I'd assume every time the ECU tries to put the throttle in a different position than the cable is putting it, the CEL would illuminate and tell you that your TPS or TPPS or both plus likely at least one or two other things were bad. So you'd have to live with a near constant check engine light, and come inspection time, it'd be tough.

You'd likely get slightly worse gas mileage if you drove with your foot on the floor all the time, but I think it'd be a very small difference. And of course the ESC would be at least partially hobbled.. it would not be able to reduce throttle in order to stop wheel spin etc.

I have considered this in concept but my Jeep only has about 1800 miles on it. Once it's out of warranty in about three years I might seriously consider it, to the point of even cracking open the throttle body and potentially machining parts. But I think there's much better chances of making adjustments to the sensor positions to reduce or eliminate lag and that dead spot without having to resort to a cable operated system.

IMHO a throttle cable is the right way to do it but with ESC required for all new vehicles we are stuck with DBW from now on, or until the law changes, which is unlikely.
 
#3 ·
I wish it was a simple procedure. I hate the drive by wire. I would switch in a heartbeat. On more than one occasion I have stalled my Jeep due to this garbage. Normally pushing in the clutch and pushing the go pedal will save you from stalling, not so much on this tech dependent Jeep. I have learned to just let it do its thing and restart the engine. And feel like a fool who can't drive a manual!!
 
#5 ·
Normally pushing in the clutch and pushing the go pedal will save you from stalling, not so much on this tech dependent Jeep. I have learned to just let it do its thing and restart the engine. And feel like a fool who can't drive a manual!!
clutch in, and let off and then re-apply the gas to "reset it" (or something) works for me...
I have only stalled mine once (so far) before figuring out how to work with the computer.... (our Benevolent Computer Overlords?)
 
#4 ·
By the time you were done, you what have worse MPG, probably lose some power, would fail any emissions testing, etc.... just not worth it...
besides drive by wire isn't that bad... I only complain about it while I am diving my jeep...
besides drive by wire isn't that bad... I only complain about it every day...
besides drive by wire isn't that bad... damn, I just cant seem to properly complete this sentence....

wonder if the hemi or LS swaps use a real throttle, or is everything DBW these days?
 
#10 ·
The others on this thread commented about two ways to address this: a reflash tool like a Flashpaq or Diablo, or using the so-called "Sprint Booster". The idea of these is to just move the curve to the left, so to speak, so the throttle opens sooner or quicker as you depress the pedal.

My own personal plan is to find some time to cram my head up under the foot well and see if I can actually move the hall sensors. Also I plan to investigate how the actuator works on the throttle body and see if there's any slack to be taken up there. Might as well start with the mechanical things you can do before adding on non-factory tuning options IMHO.

But, to answer your question, no I haven't yet investigated this. It's just one thing to look into. Might even get into it this weekend.
 
#11 ·
You can try to recalibrate the throttle and see if it helps.

1: Turn the Jeep to the “on” position but not the engine running position.
2: Wait for all of the dash lights to turn off (check engine light will stay on).
3: Depress the accelerator REAL SLOW all the way to the floor.
4: Release the accelerator at the same slow rate.
5: Turn the Jeep off.
6: Start the engine.
7: Take it for a test drive.
 
#13 ·
You can try to recalibrate the throttle and see if it helps.
Sure, it's quick and easy, and free. It won't fix the problem. There's a designed-in dead spot at the front of the travel and a 1/4-second or more delay at off-idle that pretty much are endemic to the design. You can't get around that with a factory-approved "calibration".

I don't think the delay can ever be tuned out without reprogramming the ECU. You might be able to get rid of the dead spot in the travel by modifying the pedal/sensor relationship.
 
#19 ·
The easiest way to do this would be a complete engine conversion to an engine/transmission and ECU combination that doesn't use DBW.

If you have a manual transmission, it may be technically possible to do the physical modifications for a cable-actuated throttle, then use an aftermarket ECU (like MegaSquirt) to control the engine. But that would be a massive project to get the custom ECU configured correctly. You'll also have tons of fun trying to figure to how to integrate it with the stock electronics system so that the dashboard, etc, all still works. In this aspect, it would be similar to an LS V8 conversion.

If you have an automatic transmission, it's probably nearly impossible.

The stock powertrain control system is "torque-based". The position of the pedal is not simply converted electronically to a throttle blade position. It is interpreted as a desired amount of acceleration or torque at the axle, taking into consideration the current speed and likely other things. Then a crap-ton of calculations are done to finally decide what the throttle position, ignition timing, fuel ratio, etc., all need to be to produce the desired amount of acceleration. All those calculations depend on various properly-calibrated lookup tables so the computer can make accurate assumptions about how much torque the engine is producing right now, and what combination of throttle/fuel/spark/variable-valve-timing would produce the desired amount of torque.

During these calculations, multiple sub-systems (traction control, speed limiter, rev limiter, torque management for auto transmission shifting behavior, etc) all have the opportunity to "deny" the torque requested by the driver, and limit it in multiple ways. This all involves another metric crap ton of lookup tables that must be properly calibrated.

With the auto transmission, the transmission controller is integrated into this system also in terms of desired output torque at the axle and current road speed to decide what transmission gear is best right now.

So, no... you can't just slap a cable-actuated throttle body on the engine and expect anything to work.

This is what makes it so difficult for forced induction kit manufacturers to create custom tunes. Plus, Chrysler doesn't openly share details of how the system works, what lookup tables are involved, how the lookup tables affect things, etc.

Here's an intro to how a torque-based ECU works (specifically for the Dodge Viper, but generally relevant in concept for any torque-based DBY engine system): https://www.hptuners.com/help/vcm_editor_tuning_how_to_advanced_e78.htm
 
#21 ·
Conversion would be a nightmare. You'd lose cruise control, stability/traction control, you'd need to sort out a way to keep the electronics happy without the stepper motor being there (and the throttle body not responding to the pedal position sensor) and probably a dozen other issues. Probably not impossible, but given the technical knowledge needed I'd say unless you got someone at Jeep to assist on this, it isn't happening.
 
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