I was just at my mechanic who's worked on my Hondas and Acuras for years, so I trust what he says.

I was explaining that although my RDX runs like a scalded cat at higher RPMs, off the line is rather disappointing, and recently sort of scary. I had to jump out into traffic the other day in the RDX, and there seemed to be more than the normal turbo lag.

My mechanic told me there is an adjustment that can be made on the throttle cable, taking out about 1.5 mm of slack. Apparently Honda has a full throttle delay, or something. Maybe a conservative built-in safety factor to protect the transmission.

Does anyone know about this?

If it's accurate, how easy is it to adjust the throttle cable to take out the slack? And what's the danger of taking out too much slack?

 

Drive by wire..... I thought there was no throttle cable. ??

 

The RDX are drive by wire throttle. It has no throttle cable or linkage going to the throttle body! Basically the computer controls the throttle.

 

Instead of a mechanical linkage from the accelerator to the fuel-injection throttle, Acura uses Drive-by-Wire technology. The system uses an electronic position sensor connected to the accelerator pedal that sends an electronic signal to the Powertrain Control Module. You would take up that 1.5 mm in an instant, even if there was a cable so I don't think it would make much difference.

 

Thanks.

My other car (Jag XJR) has drive by wire, but I don't think it, and probably the RDX, has any adjustment. And it's programmed to increase the initial launch off the line.

I got to test drive a Maserati Quattroporte a few months ago, which also has drive by wire. It has a de-tuned Ferrari engine in it, and it REALLY jumps off the line. The salesman (again he was a salesman) said they could adjust/re-program the initail throttle response.

Other than going to the expense of the Hondata reflash, can any adjustment be made to the RDX?

 

No point in comparing a Maseratti to an Acura SUV...come on....You can take it to the dealer and show them the problem...my dealer has been very receptive to warranty things, this sounds like it could be one of those. Plus, if you have an '07 is a first gen car, prone to have issues...

 

I think it may be called turbo lag.

 

Back late in the last century Toyota (or Toyota's supplier..??) came up with a new, more fuel efficient, transaxle design that allowed them to significantly reduce the line pressure level in most instances. The pressure holding/sustaining accumulator has been eliminated and now line pressure is "regulated"/modulated in "real time" according to the situation of the moment.

That has resulted in many of their FWD and F/AWD models not having the ability to accomplish two gear shifts, gear changes, in quick succession. Lift the throttle slightly, the transaxle upshifts, now quickly depress the gas pedal again for acceleration and the DBW system is used to delay the engine torque rise until the transaxle has enough line pressure built up to accomplish, fully seat the downshift clutches, for the newly required downshift.

Sound familiar..??

I wouldn't be at all surprised if many asian marques are now following Toyota's "lead".

 

In this case, I don't think so. I can feel the turbo lag, and it's about the same or slightly better than my last turbo. I think what we're talking about here is really throttle lag - the time it takes the car to realize you actually pressed down the accelerator and actually do something...anything. For me it's not really an acceleration issue - it's a 0-5mph issue. There is a slight, but noticeable hesitation when I hit the gas pedal, and it catches me off guard sometimes. After it starts moving, THEN I notice the turbo lag during acceleration.

I'm wondering if there's something to the transmission theory in the previous post...

Mike

 

It's in the "problems and fixes" section and what I described, along with three others, are what the original poster described. It's a stutter or delayed response when under moderate throttle - but not a turbo lag. Once you hits 3500 RPM or so, it takes off and with smooth power. Mine's going to the dealer for the fourth time to try to figure this out. Replacing the injectors did nothing.

 

I've driven four RDXs, and they all have this hesitation. It is scary to have it occur when you're trying to make a left turn in an intersection ahead of oncoming traffic.

I still attribute it to the turbo lag. Remember, off boost, you've got a low-compression 2.3L engine trying to move almost 4,000 pounds of vehicle from rest. Until the boost hits, not much is going to happen.

 

All turbos have lag of some sort. Honda/Acura has done a good job with the RDX. but it is not perfect, nor will there ever be a perfect turbo, IHMO.

 

To elaborate a bit.

The old ATF pump/pressure system maintained a constant line pressure using a spring loaded pressure relief valve and an accumulator. That's representated a CONSTANT load on the engine just as does a power stearing pump constructed in much the same manner.

The new system, in essence, allows the ECU to control the "strength" of the relief spring holding the pressure relief valve shut.

Since there is no need for any substantial level of line pressure when setting idling, say at a traffic light, the engine/transaxle ECU is able to "command" that the relief spring release fluid flow at a very LOW pressure level.

So now when you apply pressure to the gas pedal the ECU commands enough line pressure to hold the clutches more firmly seated while the DBW "holds" off on engine torque rise for a few hundred milliseconds until the ATF pressure has risen accordingly.

All toward improved FE.

 

may sound stupid but I have noticed a reduction in the throttle lag just by switching gasoline. I used to be an advid Shell Vplus user but one day decided to switch to Chevron since it was a few cents cheaper. tank was on E so there was only a lil Shell left in it so after a few dozen miles I noticed the throttle lag was almost nonapparent. it was always very noticable with the AC on but i really don't feel it anymore. when I had my evo I was an avid Chevron user and my car ran strong and reliable. swithed to shell when I got the rdx cuz of all the Shell commercials.

car has 18K miles and now on my 3rd tank of Chevron and haven't notice the lag for a few hundred mile now. just a shot in the dark but doesnt hurt to try.

 

Conversely that could be the result of you now using a poorer grade of gas. Engine tends to ping with the poorer grade, ECU enriches the mixture to prevent ping, more "residual" POWER in the exhaust stack/manifold.

 

even tho this has nothing to do with throttle, i switched from V Power (the ONLY gas I had been putting in, since the delivery tank went) to Mobil. My MPG went up 2-4 mpg across the board. go figure.

 

The only time I can sense a throttle delay is with the A/C on. It is significant enough that when I know I need to make a turn without stopping and there is on-coming traffic, I turn off the A/C to avoid the delay.

For those of you who also notice the turbo delay, can any of you say if it occurs with the same sensation with A/C on as it does when off?

 

I've noticed this with the Two test drives of the RDX including mine !
From a complete stop if you floor the throttle nothing happens for a split second then the car takes off.
However if you gradually hit the accelerator it takes off.
It seems that if you want to accelerate fast you should give the throttle a squeeze instead of flooring it!!!

 

The remedy for a Mercedes with the same problem (caused by "Drive-By-Wire" technology) is a Sprint Booster. Sprint Booster dot com only has it available for the Civic & S2000 models (for Honda products).

 

I have noticed the same issue and have a slight workaround, or at least it seems to be for me. On another thread: https://acurazine.com/forums/showthr...?t=2777&page=4 , they were discussing racing and I mentioned that if you DON'T MASH the gas pedal down, rather ease it down until you hit about 2K you will find some of that hesitation disappears.

 

Would have been nice if I read your post first before posting mine! LOL

 

Yes, with the new line pressure control technique if you "floor the throttle" virtually instantly the ECU "knows" that the clutches will QUICKLY need to be fully and firmly seated. So it uses DBW to "wait", hold off on engine RPM/torque rise, until the line pressure can be brought up to "snuff".

Whereas if you "ease" into the throttle the line pressure will be "allowed" to rise with RPM/Torque.

 

?? I always used 93 supreme here in TX. so you're saying chevron petro isn't as good? either way, I think the RDX runs rich from the factory anyways.

 

After driving a 2006 Si for a year and now my RDX, I have got used to DBW and find myself compensating by pushing the accelerator a split second before I need to move if I need to get out fast. This almost caused an accident when I drove my friends CL-Type S and had instant acceleration. Yoiks!

 

Both Shell and Chevron are "top tier" gasoline.

 

So is this basically a Torque Management Program written in the Computer to prevent shock loads on the Transmission, rear and front Differentials?
Basically if the customer beats the *.* out of the car it will hold up OK!

 

Took my wife's RDX to work today, to compare to mine. The lag is Turbo lag.

 

Relative to "top tier" gasolines. Shell and Chevron are indeed "top tier", but they use different gasoline detergents.

 

The delay I feel is definitely not turbo lag. I've had other turbos and I know what lag feels like. This ain't it.

Mike

 

In my honest opinion, what you're experiencing is Honda's lack of cajones. I don't mean this in a negative way because I have owned many Hondas and will continue to... but they have a nasty habit of assuming the worst case scenario when designing and programming the drivetrain. I have an '05 RL and experience these same delays... and from the previous posts, it sounds like the RL may have even more safeguards in the system. I consistently experience a 3-4 second delay in power delivery in my car that feels like the ignition timing is being retarded. Also, there are times when the car accelerates like a bat out of hell... and other times when it feels like the engine is producing about 150hp and can't get out of its own way.
The "new" '09 RL claims to have "re-programmed" SH-AWD software but I doubt they completely removed the restrictions. I can't wait to see the new SH-AWD 6-speed TL. It will be the first manual transmission SH-AWD vehicle and the lack of one of Honda's POS automatic transmissions should make things interesting!

 

ya im along those same lines..... Most of the time my RDX screws but then there are those times where you scratch ur head and say wtf is going on with this thing. Its the nature of the beast. It is what it is. I dont think there is anything wrong, and not sure a solution exists other than training ur foot and learning how the car behaves and its relationship to the gas pedal. A dead stop pedal mash just does not work, and with safe guards built in, and especially since its a honda/acura, I wouldnt expect the tires to screach off and to get extreme power delivery, just not gonna happen.

best case scenario, get a little roll going before you know or expect that you wana take off. and by roll, even a few mph elicits better response than a pedal mash from a stop. And on the higheway, if u have to make a high power pass or merge, ease into the accelerator, ive just found better engine response that way...but everyone is different

slight, increasing pedal pressure seems to work better for me and the RDX responds better, rather than large increments in pedal compression. just my 2

 

There is a Toyota TSB that was issued in August '03(??) for the '03 Camry that explains, in good detail, at least three circumstances wherein the DBW system will not allow the engine torque to rise quickly, supposedly to protect the drive train.

Looks as if it might be a good read for Honda/Acura owners.

 

Torque is what gets a car going. Horsepower makes it go fast. Since the RDX only has 260 ft-lbs of torque and specific gearing you can't expect neck snapping, put you back in the seat, acceleration in a 3900+# CUV. Acura could gear the RDX to get 5.0 second 0-60, but the gas mileage would be like 10 mpg overall. I am happy with the RDX as it is.