Fix for Throttle Lag

[JCUZ]

One way I improved the throttle response on the '04+ 4.0L V6 was to remove the plastic throttle body spacer. It has some little "teeth" moulded into it that allow a smoother transition from closed to tip-in throttle. Thing is, these vehicles don't need a smoother more gradual transition to tip-in...They need an improvement in such.
By eliminating this little spacer and replacing it with a standard fibre gasket, there's no more restriction at light throttle openings, which equates to a somewhat more responsive feel in the throttle response. It's getting more air quicker when the throttle is opened.

The mod is simple, and should take all of 10 minutes. It's only for the 4.0L V6, not the 4.6L V8...The V8 doen't have the same design.

First, remove the throttle body from the intake plenum, then remove the spacer/gasket. Install (1) Fel-Pro #61050 throttle body gasket* in place of the spacer. Installing the throttle body with the original bolts will require a couple washers on them to make up that difference that the spacer took up. Otherwise, it's possible to bottom out the bolts in the plenum and possibly split it. On mine, I got some new bolts that were about 1/4" (~4mm) shorter to give it a more finished look, but two or three washers on each bolt will accomplish the same thing.


The difference is quite noticeable, especially when rounding a corner and getting back into the throttle, the response is much better. These trannies still don't have the quickest downshifts and sometimes seem to get a bit confused as to what gear to be in, but aside from that, I feel it's a worthwhile mod. I also like the extra little "swoosh" noise when the throttle is just tipped in. It's very noticeable with an aftermarket intake or even a K&N drop-in filter in the stock airbox. With a standard paper filter, it's there, but much more muffled.

Considering you'll have less than $2.00 USD invested in this mod, it's definitely worth a try.

*Order the throttle body gasket for a '99 F150 4.6L if you can't get this exact brand or your parts store requests a vehicle application.

If you like your mod - try mine. You'll love it. No throttle lag at all, if you use a softish torsion spring (say from the middle of a pair of BBQ tongs). I used an actual accelerator pedal spring off a locally manufactured car, thinking it would be better than than softer spring from the tongs, but it wasn't - it was actually worse, though still not as bad as having a fixed pedal.

 

[jluv]

Weird. I have an '04 and I've never noticed any kind of throttle lag or "dead spot".

 

[Curtis]

Weird. I have an '04 and I've never noticed any kind of throttle lag or "dead spot".

I notice it most when turning on to my street. Slow down, make the corner and when I press the pedal, there is a lag of about a full second... then the 4.6 kicks in and breaks your neck!

 

[JCUZ]

I notice it most when turning on to my street. Slow down, make the corner and when I press the pedal, there is a lag of about a full second... then the 4.6 kicks in and breaks your neck!

You nailed it! That's the best description I've seen of the problem, and is EXACTLY what happens with mine - but not any more!!!

 

[blueoval9erlifer]

i know this is an older thread but im going to try it this weekend just got a donor part from the junk yard and going to get it set up then swap the original with it, looks like ill have about 7.50 usd in it.

Thanks for all the advice and help with his and the bwm jcuz and ktford

 

[briwayjones]

Let us know how it works.

 

[Definca]

Have an 05 Ex and it does have an annoying trait in the accelerator pedal. I drive pretty easy anyway, but, it seems that when you start from a dead stop you need to feed, and feed, the pedal, and THEN it finally gets going, and usually is MORE than you wanted. I was thinking it was in the rheostat in the electronic pedal, like the fine graduations at the bottom are worn and then it grabs at a higher position finally and as others stated kicks in hard.

 

[4WDriver]

Just wanted to add what info I could, and clarify a bit of what seems like missunderstanding...
I believe when BrooklynBay was asking if you'd had your PCM flashed, he was not referring to having the most updated and bug-corrected factory tune. He was most likely referring to having the factory setting modified by the dealership to delete the delay that is purposely put into the throttle response of most modern drive by wire throttle controls. That delay is put there to allow the average driver to realize better fuel economy so the manufacturer doesn't get complaints of the vehicle not getting its EPA rated MPG. You see, most people don't ease into the gas pedal and also don't realize jackrabbit starts lead to horrible fuel economy.There was a demonstration of this programmed delay on the Goss' Garage segment of MotorWeek. You can have the dealer reprogram the PCM to delete the delay (for a charge of course) but don't be mistaken, this is not a problem with the vehicle, so they do not "fix" it for free. It is the way it is intended to be. Does it suit everyone, no. Does it suit the majority, yup!
In regards to your mod, it doesn't really do anything to the system itself or effect an kind of change in the way it works, but if it allows you more feel, or to more easily, gently apply the gas pedal, AWESOME! I myself don't like non pivoting accelerator pedals either, it's just not the feel I expect. The key with a drive by wire with delay is to not get frustrated by the delay, wait for it to respond, and you'll get the gentle acceleration you want. Also, I've found if your even gentler with the pedal and apply it smoothly and evenly, the delay is actually less noticeable.

 

[Definca]

Thanks 4WDriver for that info I will discuss it with my local ford dealership. I will say however that at least on my 05 the response to the pedal is more unusual than you describe.
Example, if in park with the engine running, and you VERY slowly press down starting from not even contact with the pedal so it is at rest, what seems to happen is in the first few degrees of pedal movement the idle will come up ever so slightly, perhaps 200 rpms, THEN as you continue to a few more degrees of pedal movement, the idle will actually DROP below what it was when you had your foot off the gas, as you push through these degrees of movement it will again pick back up and raise the idle fairly sharply.

This "flat spot" does not help with throttle control or easing in the throttle in my opinion, generally when driving I end up feeding in too much to try to compensate for the delay. so in short, I do not see any benefit.

 

[4WDriver]

That sounds like normal operation when free revving the engine (not in gear). The "dead spot" and the accompanying drop in RPM as you feed more pedal are due to the IAC (Idle Air Control) transitioning from controlling the amount of air being let into the engine, to allowing the throttle plate to do so. It really shouldn't be noticeable when moving and in gear as the weight and inertia of the vehicle tend to smooth out the minor fluctuation.

Although, if it is really noticeable and annoying, you could be having issues with the IAC valve not functioning correctly or being gummed up.

My wife has a 2014 Hyundai Elantra which is of course, a drive by wire system. This car is actually kind of unique in that it has that funny little ECO button. This illustrates my point pretty well: drive one of these current Elantras with the ECO button on, you'll notice the MAJOR throttle lag. Turn off the ECO button, and it's still not fully devoid of lag, but man oh MAN, waaaay better! I actually can achieve way better milage with the ECO function off. I don't even drive like a grandma, just smooth and even with the throttle, and I can see 36 MPG CITY with this car! I have gotten 48 on the highway. And these are averages, not instantaneous numbers. I've checked the indicator on the car against fuel receipts and the odometer, and it checks out.

 

[swshawaii]

2004 and newer Explorer's use throttle by wire. No IAC.

http://www.explorerforum.com/forums/showthread.php?t=253445

 

[4WDriver]

Oh duh! LoL. And that's why we have this great forum! Thanks. I was in a mode thinking about my own Explorer when thinking about possible diagnoses. Might want to check for proper operation of all components in the drive-by-wire system, it COULD be the potentiometer in the accelerator pedal itself, or it could be problems with the other parts (wiring harness connectors, wires themselves having resistance-causing corrosion, or the actuator on the throttle body)

Thanks for keeping me on my toes, swshawaii

 

[ProjectAviator]

Is there a way to eliminate the stupid throttle by wire. change to an actual throttle cable. I hate the delay. Was wheeling yesterday and the delay drove me crazy. When I want throttle I want throttle now not ten seconds from now. ( exaggeration)

Tim

 

[96firephoenix]

you'd need to get a pedal assembly w/cable, throttle body and PCM from the older cable setup... you might also need to get injectors. Conceivably, you could tune the DBW out of the PCM by removing the signal for pedal command and the signal out to throttle control.

The fuel/air mix is still set by the throttle position sensor, so you ought to be good to just tune the pcm? Not sure how well that will work.

 

[4WDriver]

There is another option other than my preferred method of simply flashing the PCM to delete the delay... There is a piggyback plug-and-play tuner that plugs into the connector at the top of the pedal assembly that intercepts the signal from the accelerator pedal position sensor, modifies it, then sends it on its way to the throttle actuator. Check out 4Wheel Parts. I don't know if they have the application for the Explorer, but worth a look.

Also, most power programmers should be able to delete the delay as well.

 

[dfw04explorer]

Thanks eb cornburner. I followed your write up to pull the toothed spacer in the TB. It worked well. I seafoamed it at the same time so not shure which made what improvements. Made a video of the process by following your post!

Now i hope to wrap my head around the pedal spring write up that jcuz tackled for us. Hopefully these three things will give me some good measureable improvement on the cheap!

 

[360cid]

Has anyone done this to a telescoping throttle pedal? Those are mounted differently that the fixed position pedals! Wondering about the easiest way to get the pedal assy out without having to remove the telescoping part, as well as the brake pedal since they move together.