Rev-hang revisited - fix may be available soon

[stevenj]

the holycow wrote: "In fact, the consequences would be less than the proposed fuel injector control box (which would wreak havoc almost as bad as the throttle cable idea)."

It is a harsh conclusion based on so little info you know so far about my intended device. I definitely do not share your pessimism, or I would have not even started with this project. Only time will tell.
Residents in US have big advantage of not having to pay overseas shipping that doubles cost of any part, like injector connectors, I buy online from there; not to speak about the wait for parts.

[daleadbull]

Revs can hang even if you don't have electronic throttle control. The idle speed hasn't been controlled by the throttle plate position for a number of beers now.

Beer on your brain or in your system when you typed this?

[Shadow]

It is a harsh conclusion based on so little info you know so far about my intended device. I definitely do not share your pessimism, or I would have not even started with this project. Only time will tell.
Residents in US have big advantage of not having to pay overseas shipping that doubles cost of any part, like injector connectors, I buy online from there; not to speak about the wait for parts.

Good luck with your endeavor, but I honestly don't think you're going to find a market for it. Maybe a tiny niche market if you're lucky, but even that's doubtful, IMO. The fact that canned tunes rid cars of rev hang and offer other advantages, for basically the same price range means that you have a rough road ahead of you.

[stevenj]

Agreed. I am primarily developing this for my own use out of interest, deep personal hate of rev hang and as a technical challenge. Should anybody else want it, fine. I did not agree with what was written about the device not likely to work without major dramas. I briefly considered tapping into the accelerator pedal position (APP) sensor wires but rejected the idea because of fear of possible interference. Just as well, yesterday I studied the NHTSA study of unintended acceleration in Toyota vehicles (http://www.nhtsa.gov/UA) and was struck by comments like “certain aftermarket devices (e.g. cruise control systems, remote start devices) that connect directly to APP power or output signals may provide pathway for EMI (electromagnetic interference) into the APM (accelerator pedal module) circuitry.” And yet, some aftermarket devices do just that!

[Shadow]

Agreed. I am primarily developing this for my own use out of interest, deep personal hate of rev hang and as a technical challenge. Should anybody else want it, fine. I did not agree with what was written about the device not likely to work without major dramas. I briefly considered tapping into the accelerator pedal position (APP) sensor wires but rejected the idea because of fear of possible interference. Just as well, yesterday I studied the NHTSA study of unintended acceleration in Toyota vehicles (http://www.nhtsa.gov/UA) and was struck by comments like “certain aftermarket devices (e.g. cruise control systems, remote start devices) that connect directly to APP power or output signals may provide pathway for EMI (electromagnetic interference) into the APM (accelerator pedal module) circuitry.” And yet, some aftermarket devices do just that!

What kind of car do you have? If you tell me, I can point you to a canned tune that will rid your car of rev hang. It won't even cost much money.

BTW, my Audi has no rev hang whatsoever. I guess I'm just lucky. I hear that VW has quite the problem with rev hang, so I'm not sure why Audi managed to figure out how to avoid it.

[stevenj]

I appreciate your kind offer. Thankfully, presently I do not own a car with manual gearbox displaying a severe degree of throttle hang. However, I am shopping for a new car and I tried a 6-speed manual Honda CR-Z (yes, kind of a hybrid) at the dealer’s that I found difficult to drive because of it. That brought back bad memories of me buying a new 2009 Suzuki Grand Vitara 4WD (2.4 litre, manual). I did not realize it at the time but I probably drove a cold-started demonstrator and the throttle hang was not there. On my way home in the new car I found out how bad it was. I just could not bring myself to live with it as a daily drive and sold the new car back to the dealer in 6 days, losing about 23% of the purchase price. I then tried suing them for the loss but did not succeed because I sold it back to them so quickly and did not give them any chance to fix it (I knew this was not possible). Had I kept the car longer and sued them then, I would have probably won with all the expert evidence I accumulated to support my case. I also shopped for a new manual car for my 22-yr old daughter and was appalled by the 3 second throttle hang in Subaru Forester. Toyota Yaris was not as bad but I found the least amount of it in a 2010 Mazda 2. I note that driver does not feel the same problem in automatics because of the torque converter smoothing out gear changes.
In this respect the best car I have is a 1991 Suzuki Swift carburetted 1.3 litre 5-speed with cable operated clutch and throttle. It has 190000 km on the clock but is still a delight to drive. I drive it more often than my 2009 Toyota RAV4 auto or heavy Landcruiser 4.2 diesel manual. When I mentioned the Honda CR-Z earlier, I found on the Net (http://www.crzforum.com/forum/transmiss ... ve-12.html) posts about that car having a Clutch Delay Valve built in the clutch master cylinder. It has 2 small holes inside and a diaphragm that does not allow the driver to release the clutch faster than Honda specified. I did not like that either but there is a person in the States supplying modification by welding the holes shut and bypassing the diaphragm.
I want to have my device to fix the throttle hang ready for my new car, whatever make and model it eventually will be, so I am making it universal to fit anything with engine and 4 wheels .
I never heard about canned tunes. We do not have them in Australia and I would not probably be shipping ECU from a new car to the USA to have it done there.

[theholycow]

You wouldn't have to ship the ECU. You just order the tune and they ship it to you in a downloader. Plug the device in, press the button, and your car gets the tune.

Here's a highly regarded one, though it is a bit more expensive than we've been discussing:
http://www.c2motorsports.com/index.php? ... &Itemid=58

When sending an ECU it is popular to acquire a spare ECU from a junkyard and send that one for your tune, that way you always have your original.

[stevenj]

Interesting reading. Thanks. Problem with getting a spare ECU is to find a late model car offered for wrecking. If you do find it, the ECU still costs an arm and a leg. I am getting a bit too old for performance tunes and the like. After 35 years of certifying modified cars I came to believe that OEM often know the best, throttle hang excepted.

[Shadow]

I appreciate your kind offer. Thankfully, presently I do not own a car with manual gearbox displaying a severe degree of throttle hang. However, I am shopping for a new car and I tried a 6-speed manual Honda CR-Z (yes, kind of a hybrid) at the dealer’s that I found difficult to drive because of it. That brought back bad memories of me buying a new 2009 Suzuki Grand Vitara 4WD (2.4 litre, manual). I did not realize it at the time but I probably drove a cold-started demonstrator and the throttle hang was not there. On my way home in the new car I found out how bad it was. I just could not bring myself to live with it as a daily drive and sold the new car back to the dealer in 6 days, losing about 23% of the purchase price. I then tried suing them for the loss but did not succeed because I sold it back to them so quickly and did not give them any chance to fix it (I knew this was not possible). Had I kept the car longer and sued them then, I would have probably won with all the expert evidence I accumulated to support my case. I also shopped for a new manual car for my 22-yr old daughter and was appalled by the 3 second throttle hang in Subaru Forester. Toyota Yaris was not as bad but I found the least amount of it in a 2010 Mazda 2. I note that driver does not feel the same problem in automatics because of the torque converter smoothing out gear changes.
In this respect the best car I have is a 1991 Suzuki Swift carburetted 1.3 litre 5-speed with cable operated clutch and throttle. It has 190000 km on the clock but is still a delight to drive. I drive it more often than my 2009 Toyota RAV4 auto or heavy Landcruiser 4.2 diesel manual. When I mentioned the Honda CR-Z earlier, I found on the Net (http://www.crzforum.com/forum/transmiss ... ve-12.html) posts about that car having a Clutch Delay Valve built in the clutch master cylinder. It has 2 small holes inside and a diaphragm that does not allow the driver to release the clutch faster than Honda specified. I did not like that either but there is a person in the States supplying modification by welding the holes shut and bypassing the diaphragm.
I want to have my device to fix the throttle hang ready for my new car, whatever make and model it eventually will be, so I am making it universal to fit anything with engine and 4 wheels .
I never heard about canned tunes. We do not have them in Australia and I would not probably be shipping ECU from a new car to the USA to have it done there.

A couple of things: First, I'm surprised that you'd be willing to accept a 23% loss on a car that you had for only 6 days. I understand the frustration you must have been dealing with, but if the issue could have been correct with a tune, you probably would have enjoyed the car and not had to take such a ridiculous loss.

Secondly, I did not know that the CR-Z has a clutch delay valve. But I can tell you that clutch delay valves are HUGE in the BMW community and LOTS of guys remove them because they don't like them. On a BMW, it's a relatively simple & easy procedure. I can't imagine it would be too difficult on the CR-Z though... Anyway, if you want more info, just do a search for clutch delay valves on BMWs.

[Shadow]

Interesting reading. Thanks. Problem with getting a spare ECU is to find a late model car offered for wrecking. If you do find it, the ECU still costs an arm and a leg.

I'm not sure if you understand. You don't need a spare ECU. You just need to order the tune and you simply "reflash" the ECU in your car with the tune. It's a really simple procedure and it costs nothing but the original cost of the tune itself.

[tankinbeans]

Interesting reading. Thanks. Problem with getting a spare ECU is to find a late model car offered for wrecking. If you do find it, the ECU still costs an arm and a leg.

I'm not sure if you understand. You don't need a spare ECU. You just need to order the tune and you simply "reflash" the ECU in your car with the tune. It's a really simple procedure and it costs nothing but the original cost of the tune itself.

He's responding to cow.

When sending an ECU it is popular to acquire a spare ECU from a junkyard and send that one for your tune, that way you always have your original.

[potownrob]

sorry i had to

[stevenj]

In 2009 with Suzuki and now with my future new car I would be reluctant to get its original ECU flashed when under warranty. Then I did not know about the availability of tunes and, more importantly, the Vitara also had a problem with incredible drive line free play or snatch. I have a letter from Suzuki confirming it was a "design feature". When stationary and in neutral, one could turn the drive shaft by half inch when measured on its circumference (some 14 degrees of angular movement). I reckoned the dif could be properly shimmed eventually but I could not think of any fix for the throttle hang. Yeah, I got burnt badly with the Suzuki but I did not expect I would lose the law suit. Finally, what times are we living in when a new car has to be modified to be enjoyable? Of course, I could always buy an Audi to avoid the above dramas but they are expensive in Australia.

[Shadow]

In 2009 with Suzuki and now with my future new car I would be reluctant to get its original ECU flashed when under warranty. Then I did not know about the availability of tunes and, more importantly, the Vitara also had a problem with incredible drive line free play or snatch. I have a letter from Suzuki confirming it was a "design feature". When stationary and in neutral, one could turn the drive shaft by half inch when measured on its circumference (some 14 degrees of angular movement). I reckoned the dif could be properly shimmed eventually but I could not think of any fix for the throttle hang. Yeah, I got burnt badly with the Suzuki but I did not expect I would lose the law suit. Finally, what times are we living in when a new car has to be modified to be enjoyable? Of course, I could always buy an Audi to avoid the above dramas but they are expensive in Australia.

Personally, I'd have no worries because a flashed tune is reversible. And as far as modifying cars in this day and age, it's the same old thing I've been doing my entire life. I've yet to find a car that I found 100% perfect, so I always make some changes to my cars to make them perfect for me.

[ClutchDisc]

I appreciate your kind offer. Thankfully, presently I do not own a car with manual gearbox displaying a severe degree of throttle hang. However, I am shopping for a new car and I tried a 6-speed manual Honda CR-Z (yes, kind of a hybrid) at the dealer’s that I found difficult to drive because of it. That brought back bad memories of me buying a new 2009 Suzuki Grand Vitara 4WD (2.4 litre, manual). I did not realize it at the time but I probably drove a cold-started demonstrator and the throttle hang was not there. On my way home in the new car I found out how bad it was. I just could not bring myself to live with it as a daily drive and sold the new car back to the dealer in 6 days, losing about 23% of the purchase price. I then tried suing them for the loss but did not succeed because I sold it back to them so quickly and did not give them any chance to fix it (I knew this was not possible). Had I kept the car longer and sued them then, I would have probably won with all the expert evidence I accumulated to support my case. I also shopped for a new manual car for my 22-yr old daughter and was appalled by the 3 second throttle hang in Subaru Forester. Toyota Yaris was not as bad but I found the least amount of it in a 2010 Mazda 2. I note that driver does not feel the same problem in automatics because of the torque converter smoothing out gear changes.
In this respect the best car I have is a 1991 Suzuki Swift carburetted 1.3 litre 5-speed with cable operated clutch and throttle. It has 190000 km on the clock but is still a delight to drive. I drive it more often than my 2009 Toyota RAV4 auto or heavy Landcruiser 4.2 diesel manual. When I mentioned the Honda CR-Z earlier, I found on the Net (http://www.crzforum.com/forum/transmiss ... ve-12.html) posts about that car having a Clutch Delay Valve built in the clutch master cylinder. It has 2 small holes inside and a diaphragm that does not allow the driver to release the clutch faster than Honda specified. I did not like that either but there is a person in the States supplying modification by welding the holes shut and bypassing the diaphragm.
I want to have my device to fix the throttle hang ready for my new car, whatever make and model it eventually will be, so I am making it universal to fit anything with engine and 4 wheels .
I never heard about canned tunes. We do not have them in Australia and I would not probably be shipping ECU from a new car to the USA to have it done there.

A couple of things: First, I'm surprised that you'd be willing to accept a 23% loss on a car that you had for only 6 days. I understand the frustration you must have been dealing with, but if the issue could have been correct with a tune, you probably would have enjoyed the car and not had to take such a ridiculous loss.

Agreed. I'm also surprised that he didn't notice rev hang that was that bad until the drive home. If the rev hang was that bad wouldn't it have been apparent on the initial test drive?