RPM won't exceed 4,000 in park or neutral...

uss_essess · Post by **uss_essess** » Mon Jul 11, 2005 10:36 am

Not sure if this is a transmission problem or not, but I will post here anyways. (Nice forum, btw.)

I was pulling out of the parking lot at work this morning, and was halfway into the road when I noticed some guy hauling ass decided to change lanes on me. Rather than slowing him down with my rear bumper, I decided to floor it and get the hell out of his way. Unfortunately, my 2000 Nubira automatic had other plans. When I hit 4,000 RPM the car quit spooling up, dropped back down to 3,500 RPMs, and then kicked back in, until it hit 4,000 RPMs again, and repeated the process. I pulled over before I could go hood surfing on the car behind me, the car exploded, or I got a concussion from all the lurching. (If it had gone on any longer I would have needed a pair of sh*t kickers, chaps, and one hand tied to the steering wheel. Yeehaawwww, Baby!) I waited about a minute for an opening in traffic, and pulled out slowly and passed the 4,000 rpm mark with no problems. I decided to see if I could recreate the problem, so when I got the next red light, I popped it in neutral and floored it. Same thing happened, it hits 4,000 rpms, then sounds like its going to stall, and kicks back up at 3,500 rpm. Tried it in Park, and got the same results. I couldn't get it to happen in gear though. I tried starting out in 1st, 2nd, 3rd, D, with and without the power button on, and it was fine. Anyone else had this problem, or have an idea what I broke? :P

MMamdouh · Post by **MMamdouh** » Mon Jul 11, 2005 11:07 am

you broke nothing... Engine managment system on an auto tranny Daewoo won't let you rev the engine past 4000 RPM in neutral or park.

if you wanna rev past 4000 RPM get a manual tranny

MMamdouh

tango · Post by **tango** » Mon Jul 11, 2005 2:23 pm

<scratching chin> Very strange indeed. Is your car turbocharged or does it have any other mods? It sounds like a problem I used to have with a bad MAP sensor. I am not sure which auto cars Mmamdouh is talking about, but my Cielo automatic revs clean to the rev-limiter in neutral and park. I have the 3-speed TH-125C.

MMamdouh · Post by **MMamdouh** » Tue Jul 12, 2005 11:00 pm

i don't have an auto or even tested one before but Peter Blaise from the daewootech yahoo group mentioned that a couple of times on the forum.

Peter got an auto so i am sure he knows what he is talking about... also maybe your car got different managment system than the current Lanoses and Nubes.

MMamdouh

AcingTeam · Post by **AcingTeam** » Wed Jul 13, 2005 1:23 am

mmamdouh wrote:i don't have an auto or even tested one before but Peter Blaise from the daewootech yahoo group mentioned that a couple of times on the forum.

Peter got an auto so i am sure he knows what he is talking about... also maybe your car got different managment system than the current Lanoses and Nubes.

MMamdouh

I'm with MMamdouh on this one. I definately heard somewhere (here or daewootech yahoo group) that neutral revs are limited to 4k rpm.

kinkyllama · Post by **kinkyllama** » Wed Jul 13, 2005 4:57 am

I also heard they wont exceed 4k

tango · Post by **tango** » Wed Jul 13, 2005 6:13 am

You folks have HEARD this. I am TELLING you...my car hits the limiter in neutral and in park. In any event, neutral or park revving to 4000 or 40,000 doesn't help USS...his car was IN GEAR when it first happened. The man's got other issues that need sorting out and here we are bitching about neutral gear rev limiters.

TheGreatAndPowerfulOz · Wed Jul 13, 2005 6:26 am

My automatic Lanos WILL NOT exceed 4K RPMS in neutral.
Even with the car in park, you can open the hood and turn the throttle with your hand and make it go to 4K RPMS and it will suddenly stutter and act like it will quit, but picks right back up.

It is the ECU reve limiter on the cars with an automatic transmission.

Cliff

tango · Post by **tango** » Wed Jul 13, 2005 7:12 am

What we have here is a situation of different programming of the ECUs. My car has a 3-speed TH-125C/3T-40 and you guys have the 4-speed TH-440-T4/4T-60, so that should account for the difference. However...nobody's answering the question that USS is asking!

DomWoo · Post by **DomWoo** » Wed Jul 13, 2005 7:33 am

my lanos also will not exceed 4k in N or P or at all... dammit i have to get that bastard back together

MMamdouh · Post by **MMamdouh** » Wed Jul 13, 2005 8:50 am

tango wrote:What we have here is a situation of different programming of the ECUs. My car has a 3-speed TH-125C/3T-40 and you guys have the 4-speed TH-440-T4/4T-60, so that should account for the difference. However...nobody's answering the question that USS is asking!

thats what i said when you mentioned you got 3 speed tranny... a different managment system is a must and that explains why you can rev up to the rev limiter in neutral.

as for USS: this issue reminds me with the problem of not beeing able to start an auto tranny daewoo when in park or something... it was due to a brakes light switch or so. maybe their is a switch or something that tells the ECU that the car is in neutral or park and that switch was miss behaving and told the ecu that the car is in neutral or park so the ECU set the rev limiter to 4000 RPM.

again i am not an auto tranny expert but this is the most logical explanation i could get... we need someone to tell us if such manual/park indecator switch does exist and where?

BTW: what is the point of restricting auto daewoos from revving past 4000 RPM in neutra/park positions??

MMamdouh

scarr · Post by **scarr** » Wed Jul 13, 2005 10:13 am

I'm not too sure what could be the cause of this. I've never experienced it in my Lanos. But I do remember driving my mom's old Taurus a few times and while turning the car seemed to jump in and out of gear (into neutral and out of neutral) because it would go, then jerk like it was in neutral and then jerk again as the tranny went back into gear. We never could figure out why the car did that. It only did it while turning.

If thats the case, why would a tranny change gears like that while turning?

MMamdouh · Post by **MMamdouh** » Wed Jul 13, 2005 10:17 am

turning means g force... you might have low tranny fluid and during turns it accumilates at one side causing some shortage and thus jerking... not really sure.

also could be the steering mechanism caugh some wires related to the tranny control harness and when turning some wires miss behave and cause disrupted ginals to the tranny... again this is all guessing.

MMamdouh

MMamdouh · Post by **MMamdouh** » Wed Jul 13, 2005 10:20 am

mmamdouh wrote:
maybe their is a switch or something that tells the ECU that the car is in neutral or park and that switch was miss behaving and told the ecu that the car is in neutral or park so the ECU set the rev limiter to 4000 RPM.

MMamdouh

OK if that is the case then why did the ECU keep the tranny in gear while it is receiving a signal saying "the car is in neutral"??... this is really confusing

MMamdouh

tango · Post by **tango** » Wed Jul 13, 2005 12:11 pm

mmamdouh wrote:...as for USS: this issue reminds me with the problem of not beeing able to start an auto tranny daewoo when in park or something... it was due to a brakes light switch or so. maybe their is a switch or something that tells the ECU that the car is in neutral or park and that switch was miss behaving and told the ecu that the car is in neutral or park so the ECU set the rev limiter to 4000 RPM.

again i am not an auto tranny expert but this is the most logical explanation i could get... we need someone to tell us if such manual/park indecator switch does exist and where?

The brake lamp switch you're talking about has to do with the shift lock. The brake lamp switch disengages the shift lock on the Leganza's tranny and allows the lever to come out of Park. When the switch is bad, the manual release has to be used. I think a truly educated guess can't be had until we find out what sort of mods have been done to this car.

BTW: what is the point of restricting auto daewoos from revving past 4000 RPM in neutra/park positions??

It would seem logical to me to assume that the manufacturers have programmed this to protect the mechanicals. In park or neutral the engine is under no load and redlining an engine under zero load is worse than doing so when the car is actually moving.