DBW Lag, Kickdown Delay, or the VTEC?

[rustam54]

Dear All,
This is more of a knowledge share request rather than actual troubleshooting as I have neither the tools nor the skills to fix this one on my own. Maybe some day, some ECU upgrade comes along that would fix this issue.

The car in Question: Honda City 5th Gen. (L13Z)
Variant : Automatic

The issue:

Most of the City 09 onward users (and may be some of 8th Gen Civic as well) feel that the vehicle despite having improved engine control, lacks the old school response in everyday drive. We are not talking about the occational adrenaline strokes of acting all sporty. Just the usual normal paced everyday commute.

Its like the car has a mind of its own. And instead of playing active, the engine + transmission response is rather dumb.
Let me explain the scenarios.

Case1: You start from standstill. The torque is pretty good. And on same lines, one expects it to go linear. But then, in the second and 3rd gears, the 1200 to 2500 rpm is always sluggish. Everytime the engine goes beyond 2600 rpm, the engine starts breathing, the roar starts coming in. And you wish, may be it could do this in the lower rpm range but never. 2600 rpm fix everytime. The logical explanation is I-VTEC (as I have mostly said in earlier threads) but where is the Intelligent part??? It should vary the VTEC point based on load.

Maybe honda called it I-VTEC that after the desired highway crusing speed is reached, the VTEC disengaes, closing 4 intake valves and the same time throttle can go to near WOT and thus avoid intake pumping loss. How this all works, and how thats supposed to be intelligent is beyond my understanding.

Case2: You are cruising in lets say gear 4, you need to overtake and therefore push the accelrator. Turns out, the car is thinking........and thinking........and thinking.............. And if you press a little more, there we have it, the kickdown, the high revs and due to delayed realization that the user needs more input, an increasing speed that requires sudden modulation that no..no...my dear IVTEC...I dont need that much.....Please relax yourself.......and there is the 4rth gear again. And as if it only wants to cruise with that RPM.....Dont ask her to do that overtaking stuff for you again....

And by the way, as it kicks down, it always is beyond 2600 rpm.

What i fail to understand that, is it truely the blessing of a DBW. or the Trany shift map is not timed perfectly. This irregular, non-linear response actually hinders driving confidance. Some aftermarket add-ons and maybe placebo claim to decrease this as shown below. (0:50 - 1:20 relavant)

//youtu.be/0yrBpL45u-k

I'ld really appreciate if you guys can shed some light on this....preferably the members who own this variant and the ones who actually change/program ECU VTEC point and Transmission shift logic.

Thanks

[rustam54]

And i am comparing it with the L15A iVTEC from Steermatic. That one despite having a same decreased power band between 1.2-2.5k rpm has an impressively fast kick down. Indeed thats a CVT but the kickdown response time is way better.

[waleed80]

very very valid observation. i have noticed the same in my city as well. just engine to engine comparison, Swift is much more responsive in lower RPMs. this lag phenomenon is further valid during hikes. like u expect to be having a 100 hp car with a fairly reasonable power to weight ratio, cruising lets say in 4th gear on murree expressway as if everything is perfect, and suddenly there is a little bit of increase in incline, u push the accelerator, and it seems as if engine has slept enjoying the wonderful weather, until it crosses the approx 2.4k rpm and bang....yes sir...its back. in swift, this is not the case, at least its my experience

[irfansiddique]

common problem in DBW as it requires some thinking before processing your request. . . same problem in my 8Gen.

[salik990]

common problem in DBW as it requires some thinking before processing your request. . . same problem in my 8Gen.

u can get E-throttle to make it better response.....m using it on my civic reborn

[spectra]

Honda engine are always torquey at comparatively higher revs and are performance oriented. maybe because of the bike engine legacy and history

DBW further complicates the problem and you end up with a thirsty engine with a moody power delivery.

[spectra]

I have a swift and it is marginaly better at lower rpms compared to hondas, otherwise there are better examples by other mainstream manufacturers.

very very valid observation. i have noticed the same in my city as well. just engine to engine comparison, Swift is much more responsive in lower RPMs. this lag phenomenon is further valid during hikes. like u expect to be having a 100 hp car with a fairly reasonable power to weight ratio, cruising lets say in 4th gear on murree expressway as if everything is perfect, and suddenly there is a little bit of increase in incline, u push the accelerator, and it seems as if engine has slept enjoying the wonderful weather, until it crosses the approx 2.4k rpm and bang....yes sir...its back. in swift, this is not the case, at least its my experience

[syncview]

how many kilometers on your car?

[rustam54]

very very valid observation. i have noticed the same in my city as well. just engine to engine comparison, Swift is much more responsive in lower RPMs. this lag phenomenon is further valid during hikes. like u expect to be having a 100 hp car with a fairly reasonable power to weight ratio, cruising lets say in 4th gear on murree expressway as if everything is perfect, and suddenly there is a little bit of increase in incline, u push the accelerator, and it seems as if engine has slept enjoying the wonderful weather, until it crosses the approx 2.4k rpm and bang....yes sir...its back. in swift, this is not the case, at least its my experience

Glad to see I am not the only one over-thinking this phenomena. The sleepy attitude at cruising speed is no doubt annoying.

common problem in DBW as it requires some thinking before processing your request. . . same problem in my 8Gen.

Well this common problem might lead to over-take misjudgment in a country like Pakistan especially on a GT road. Same as when some highway driving amateurs face driving a loaded car on CNG.

u can get E-throttle to make it better response.....m using it on my civic reborn

Yes these devices can be the solution provided they dont affect vehicle safety. OBD fault is not an issue. But a stuck controller in one of these devices can lead to disaster. The pedal sensor itself is a variable resistor. Nothing intelligent in it. Plus there are two parallel circuits for ECU to read (redundancy) especially in the Honda's.

Honda engine are always torquey at comparatively higher revs and are performance oriented. maybe because of the bike engine legacy and history

DBW further complicates the problem and you end up with a thirsty engine with a moody power delivery.

Well a compact family sedan ought to be torquey in the lower revs.

how many kilometers on your car?

Good question, it has crossed 10k. Hence its safe to say the engine break-in is almost over.

[rustam54]

Any more inputs by fellow members????

Any suggestions may be......[other than High Octane :)]

[Xulfiqar]

Its an inherent trait of DBW specially on simpler control units, having a small engine makes it worse. Usually only older drivers feel this dead zone - as most new drivers of the world are toaster operators, for them the pedals are binary devices - ON OR OFF. Anything not resulting in pressing the binary switch and they call the manufacturer. Who tells them its normal - so they just carry on. They have not used an analog manual system.

[rustam54]

I was awaiting your reply. Actually the DBW and Auto combo makes this worse. Total lack of driving accuracy and smoothness. However if you switch it to D3, and drive it around 3k rpm, you have much better control.

I was hoping there could be some solution. The self integrating feature by ECU to input signal is of less use. To be honest, I was thinking on the lines that maybe ECU is slow :). But if it can manage all other IOs in the engine, whats up with the downshift and accel attitude??

Its an inherent trait of DBW specially on simpler control units, having a small engine makes it worse. Usually only older drivers feel this dead zone - as most new drivers of the world are toaster operators, for them the pedals are binary devices - ON OR OFF. Anything not resulting in pressing the binary switch and they call the manufacturer. Who tells them its normal - so they just carry on. They have not used an analog manual system.

[RN427]

Guys me too experienced this problem...I purchased one white ASPIRE manual and it had moody performance sometimes the pick was great and sometimes it was worse than ever...Have no idea about the reason for this...Maybe because I used to drive it completely on regular petrol and never used high octane as Honda also recommends High Octane for new City!!!

Don't know why it had moody behaviour but what i noticed was that it had power lag when the weather was hot and whenever the weather got cold the performance was really good!!!

Now by the grace of Almighty Allah, I sold my Aspire Manual and booked a Honda ASPIRE Prosmatec in Alabaster Silver Metallic and have given the delivery time of 3 weeks from Honda Centre Rawalpindi!!!

I am expecting a lot from the car and i hope it won't be having any power lagging issues whatsoever and the PROSMATEC TECHNOLOGY won't let the car change gears earlier and behave in the same way like in CIVIC REBORN!!!

How would you guys rate my upcoming car??? Please give comments!!!

[rustam54]

Okay here is an interesting info on the subject. Please review the below link. Figure 1 is of most importance but the whole article sums it up pretty nicely. Its not about the product, its about how the ECU behaves in stock conditions to pedal input.

http://www.peony888.com/VS/SprintBooster.pdf

So Sprint Booster/ E-throttle/ Blitz Throttle Controller, all do the same thing. Amplify the signal so that you dont have to press hard to get that feel. Couple of Op-amps set to about 1.3 times gain to compensate for "Less Sensative" Throttle Opening around 1/4 pedal depression.

[kasaas]

sorry to bardge in a very electronic discussion but is this the reason that my city 11 auto accelerator sometimes needs to be almost floored in reverse gear to get a responce??!

[rustam54]

Well sir, probably the same reason. Its rather better to have this delay in reverse to avoid sudden pickup. Some times your reflexes are down (especially after a heavy meal) and one can make serious mistakes while reversing even though you are experienced. Mercedes and BMW claim to have this less sensitivity in the reverse gear.

However, with the city, its not like you have to floor it. For example, reversing on a garage ramp, you might need to press it to 50% for engine to respond.

sorry to bardge in a very electronic discussion but is this the reason that my city 11 auto accelerator sometimes needs to be almost floored in reverse gear to get a responce??!

[syncview]

Good question, it has crossed 10k. Hence its safe to say the engine break-in is almost over.

Nope man, it has just started

You find the same thing in the new corollas, same lag, only difference that most toyota engines are timed so they are torquey in low revs

[accord7362]

Rustam G !!! Sarkar Steermatic Wala kick down or kaheen nahee milay gaa :P;)
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bakeeon koo kick kay saath sotiaan bhee marnee parteen hainn -#

[mustafa8228]

sir , a great thread

the rpm analysis is very very accurate and the 4th gear story is also true if yr speed is less than 60-65

as compared to models in the past:
a friend of mine has city 2000 1300cc hypervalve and has done about 200,000kms (w/o cng) .. its clutch plate has gone bad and adds extra resistance to the drivetrain.. but when i drove it a few days ago for the first time , the first thing i noticed was that IT WAS MORE RESPONSIVE THAN MY NEW CITY IVTEC !!!! HOW HOW HOW echoed in my mind
but in just a few seconds , i got the answer!
WHY???:
his car barely used to give a fuel eco of 8km/l while my ivtec gives 11-13km/l

CONCLUSION:
an international conspiracy of car manufacturers to torture car enthusiasts who want to enjoy torque at low levels using fuel efficiency and low CO2 emission levels and saving the world blah blah blah as an excuse

but now comes the ivtec part , intelligence of vtec
it gives fuel efficency so we can save a few $$$$$$ and at the same time gives HELL lot of power in its power band of rpm
so we shud take the adv of both the extremes...

[rustam54]

Rustam G !!! Sarkar Steermatic Wala kick down or kaheen nahee milay gaa :P;)
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bakeeon koo kick kay saath sotiaan bhee marnee parteen hainn -#

Aamir bhai, bilkul sahi farmaya ap ne. Puranay waqton mn bachay, kabhi kabhar shoq poora krne ke liye apni bike ghar chor kr waalid ki gardi drive pe le jaatay thay.

Zamaana kuch aisa aa gya hai....k mn apni I-VTEC chor k, chotay bhai ki steermatic chori se le jata hn

sir , a great thread

the rpm analysis is very very accurate and the 4th gear story is also true if yr speed is less than 60-65

as compared to models in the past:
a friend of mine has city 2000 1300cc hypervalve and has done about 200,000kms (w/o cng) .. its clutch plate has gone bad and adds extra resistance to the drivetrain.. but when i drove it a few days ago for the first time , the first thing i noticed was that IT WAS MORE RESPONSIVE THAN MY NEW CITY IVTEC !!!! HOW HOW HOW echoed in my mind
but in just a few seconds , i got the answer!
WHY???:
his car barely used to give a fuel eco of 8km/l while my ivtec gives 11-13km/l

CONCLUSION:
an international conspiracy of car manufacturers to torture car enthusiasts who want to enjoy torque at low levels using fuel efficiency and low CO2 emission levels and saving the world blah blah blah as an excuse

but now comes the ivtec part , intelligence of vtec
it gives fuel efficency so we can save a few $$$$$$ and at the same time gives HELL lot of power in its power band of rpm
so we shud take the adv of both the extremes...

Sir, indeed very true.

But not every day is a quarter mile (as per your signature :)). You cant just keep the engine screaming for that push-in-the-seat feel.
Sometimes, a little low end torque makes the day beautiful.