Aveo rpm delay

dw · Post by dw » Fri Jun 03, 2005 1:17 pm

I have the Aveo 1.6ltr 5spd, I'm looking for a solution to an rpm delay that occurs generally on shifting gears above 3000 rpm....(usually 3500-4500) there is a delay of about 3 seconds before the rpm start to drop off. does anyone have insight on what is causing this and what the fix might be, the car has about 700 miles on it,I have reset the ECU,and done the 15 minute relearn as posted on another thread.my local dealer does not know,chevrolet/gm has refered me to another dealer,their service guy says they haven't sold enough Aveo's to know much about them. Thanks in advance to anyone who has an idea how to fix.

dw · Post by dw » Fri Jun 03, 2005 2:11 pm

Note: this condition is only upper rpm as stated,or at least is more pronounced in upper rpm shifts, just annoying,I am hoping its not a part of the ECU design.

MMamdouh · Post by **MMamdouh** » Fri Jun 03, 2005 2:17 pm

do you mean it keeps on 3500 or 4000 RPM when you take your foot off the throttle to shift gears?
do you take 3 seconds to shift?
can you replicate the problem with the car at a halt and not in gear?
have you cheked the throttle control cable?
do you have a CEL?

MMamdouh

dw · Post by dw » Fri Jun 03, 2005 3:05 pm

no CEL,haha no I dont take 3 seconds to shift but this delay does affect how I am accustomed to shifting,in other words when shifting normally your objective in a split second is to match engine rpm with road speed,downshifting or up shifting....with this delay it interferes with the ability to do that

dw · Post by dw » Fri Jun 03, 2005 3:15 pm

only while driving,not when parked,throttle cable fine....I noticed be cause I dont have this type of throttle responce on any vehicle I have ever owned

dw · Post by dw » Fri Jun 03, 2005 4:40 pm

Is it possible that the ECU is set up with a "bias" toward the use of an automatic trans rather than a manual shift,because you wouldn't notice this in an automatic and may even coincide with certain shift parameters for the automatic application?

Daniel · Post by **Daniel** » Sat Jun 04, 2005 8:55 am

I think this is relative to emission control by ECU. Also my Nubira takes some time between gears to revs down but in less than 3 seconds. I guess the only way to avoid this is to modify the ECU software.

Daniel

DJ Kos · Post by **DJ Kos** » Thu Jun 23, 2005 12:52 am

I have a 05 Aveo and I have noticed this too. You let off the gas to shift and it takes a while to rev down. My Suzuki Swift Gt's I had in the past never did this neither did any other cars I had either. I would like to know about this problem too.

tango · Post by **tango** » Thu Jun 23, 2005 11:55 am

I've heard about this situation on Lanos', BMW M5's, Mini Coopers, Ford Focus', Subaru Impreza WRX's....you name it. And every single time I've heard it mentioned there is some reference made to emissions. I've been trying to find out how it is that holding the revs on lift-off reduces emissions, but I haven't found it yet. I wouldn't discount a sticky throttle linkage spring though. Have a look at that and open and close it by hand a few times and see if it sticks.

MMamdouh · Post by **MMamdouh** » Thu Jun 23, 2005 1:33 pm

could be the engine managment keeping too much air coming to the engine when throttle is fully closed and engine is revving at 3000 or so just to keep the mixture from riching out and making too much carbon monoxide or so...

i am not 100% sure of this but i heard that lift off on some cars can cause a flame in the exhaust cause the air is suddenly cut off due to closed throttle but the fuel is still too much for the current running condition so the mixture rich out and the unburned fuel gets burned in the hot exhaust and cause the flames.

maybe this is a close explanation to why cars take long to rev down or maybe it has nothing to do with it... i am not really sure.

MMamdouh

tango · Post by **tango** » Thu Jun 23, 2005 10:16 pm

Okay, that makes sense.

scorpionaveo · Post by **scorpionaveo** » Fri Sep 30, 2005 1:18 am

Has anyone ever thought of a heavy flywheel???? My Honda Civic Sir held the rpms a little between high rpm shifts with the stock flywheel, and after i changed it for a lightned one the engine reved up quicker and dropped rpms quicker

MMamdouh · Post by **MMamdouh** » Fri Sep 30, 2005 1:27 pm

could be that too... try fitting a lighter fly wheel then give us feedback after your test drive.

MMamdouh

derost · Post by **derost** » Sat Oct 01, 2005 12:07 am

I was going to suggest the flywheel also. I have been trying to find out if any other cars out there had the same sized flywheel as the Aveo, but no luck yet. If a honda flywheel could fit, then Unorthodox makes some super lightweight flywheels.

Not trying to jack the thread here, but on an auto tranny, the torque converter bolts to the flywheel, right? Could you not then remove alot of material from the flywheel to make it lighter, making sure you retain the strength and bolt holes of course?

Brian5475E · Post by **Brian5475E** » Sat Oct 01, 2005 2:41 am

The one off the 1.5L will fit and it is lighter. but good luck finding one