RPM's drop during shift

[240-porkchop-sx]

Hey peeps
I dunno if this is normal, but i noticed that b/w shifts my rpms don't stay up...say i'm shifting at 2500, shouldn't the rpm's hang there for abit so i can put the next gear in. At least thats what my supra did.
Mine just drop as soon as the clutch is engaged.

Please let me know if this is a problem .

thanks

[Brian]

thats how it works man.
learn to deal with it.


so on your supra, the RPM stayed the same when you clutched in to shift?
what about when you are really driving and shifting at let's say 5000. would you shift and it stayed at 5000?
i don't think so.

[Kid Zelda]

Originally Posted by 240-porkchop-sx

Hey peeps
I dunno if this is normal, but i noticed that b/w shifts my rpms don't stay up...say i'm shifting at 2500, shouldn't the rpm's hang there for abit so i can put the next gear in. At least thats what my supra did.
Mine just drop as soon as the clutch is engaged.

Please let me know if this is a problem .

thanks

REV MATCH IT !@!#

[240-porkchop-sx]

So your telling me theres no rpm hang on this car? and your car does the same thing?....hmm, pretty shitty engineering on nissan's 1/2.

On most the standards i've driven...(i cant remember my ka24e) the rpms will hang for a breif moment when you shift.

[skatanic28]

its not an electronic throttle...so theres no bullshit like that on our cars.
if you want to revs to fall slower, help yourself to a heavy ass flywheel.

[Yoshi]

Originally Posted by 240-porkchop-sx

So your telling me theres no rpm hang on this car? and your car does the same thing?....hmm, pretty shitty engineering on nissan's 1/2.

On most the standards i've driven...(i cant remember my ka24e) the rpms will hang for a breif moment when you shift.

wtf, I'm driven lots of stick cars, this is the first I've ever heard of this... why would u want the revs to stay up? That might be fine if you want a luxary type ride that simulates an auto tranny (why?!), every performance car I've heard of has lightened flywheels and quick rev/wind-down... quick response that does EXACTLY what you tell it; it's called Driver Control... The only car I can think of that sort of does that is some ferarris with all their automated silliness.

[240-porkchop-sx]

electronic throttle? a supra doesn't have electronic throttle.
I'm not sure you guys know what i'm aking about, it's almost like theres no vacuum and the idle drops to like 400, then back up to normal idle.

I'm know DJ_sunrise was having a similiar prob, ecu gave him a 34 - knock sensor, but this was with turning the steering wheel.

I kinda find it hard to believe that this is normal for a ka24de...dropping to 400 b/w shifts or coming to a stop sign!?!

Just try it out....drive nomal, then at 2500 push the clutch, and on most cars i've driven the rpm will hang for like 1/2 a second, then drop. I'm not talking about racing through all my gears here...just daily driving.

anways, thanx for your input

[skatanic28]

i didnt think they had e-thottles, im just sayin there is no place for slop in a closed mech system. you get off the throttle and the throttle plate closes. push in the clutch and the motor and driveline are disconnected. with most of the rotational intertia now gone, and little air coming in, the motor revs down.
sounds like you want a car with a sticking throttle?

anyways dropping to 400 does seem pretty strange. how slow are you shifting that itll fall that far so fast? i probably drop like 1k or so between shifts, pretty much right where it should be to match the next gear.

[Bbandit]

all of the manual cars I've driven, the RPM always drop between shifts.
Thats not engineering, thats how it works.

[kingsol]

Originally Posted by 240-porkchop-sx

Hey peeps
I dunno if this is normal, but i noticed that b/w shifts my rpms don't stay up...say i'm shifting at 2500, shouldn't the rpm's hang there for abit so i can put the next gear in. At least thats what my supra did.
Mine just drop as soon as the clutch is engaged.

Please let me know if this is a problem .

thanks

do you think that you were still on the gas a bit when you steped on the clutch? how long have you been driving stick, because this sounds like a stupid question...

[aznpoopy]

Originally Posted by 240-porkchop-sx

I kinda find it hard to believe that this is normal for a ka24de...dropping to 400 b/w shifts or coming to a stop sign!?!

Just try it out....drive nomal, then at 2500 push the clutch, and on most cars i've driven the rpm will hang for like 1/2 a second, then drop. I'm not talking about racing through all my gears here...just daily driving.

ok you gotta clear this up a little. cruising to a stop sign, off the gas, on the clutch and brake from 2500rpms. from what you are saying, it sounds like the rpms drop quickly to 400 rpms, hangs again for a bit, then bumps itself up to the 900ish idle speed.

my 1995 240sx ka24de hangs for a bit when i let off the gas while revving the car in neutral. i think you are confusing a 'feature' of the 240 and a seperate mechanical issue. the revs in a 240sx don't drop super fast but i'm guessings it's just faster then what you are used to.

dropping to 400 is abnormal. you have a problem with your idle... (as do most old 240sxs). while stopped and turning the wheel with the power steering u suck alot of power from the engine. thats why dj sunrise's idle gets erratic. for your car, it sounds like the system can't adjust from open and going to closed throttle idle fast enough. start by checking the idle air control valve and cleaning it out.

[aa87]

Even my buddies Rx8 drops rpms, and that has throttle by wire.

[AKADriver]

Yeah... GOOD throttle by wire setups (for performance) will act just like a throttle cable, only doing their own thing when working as part of the traction control/stability control systems. There are some DBW setups that will hold revs high during shifts, and it's intrusive. I've heard the Subaru Forester Turbo is like this, I hope the Legacy GT doesn't do it too.

Dropping revs quickly to 400 means you've got a problem with your idle circuit, or a vacuum leak.

[240-porkchop-sx]

Ok i'll try to be more specific.
And all my vehicles have been stick for the 7 yrs i've legal to drive... so i know how to drive.
I realize that obviously when u engage the clutch the rpms will drop! Thats not what i am trying to ask about.
Usually there will be some latency from when the clutch engages and the rpms drop, it could even be 0.5 of a second. BUT on my car there is no latency, it just drops like a bad habbit. Thats not such a big deal when i'm shifting up. Now when downshifting the engine rpm drops soon, so rather then engine sync'ing up a 1000-2000rpm, it drops lower then it should....again not really a big issue, i can live with it. BUT when coming to a stop sign, so i enage the clucth at about 1200-1500rpm to take the car out of gear, the rpms drop to like 300-400, then kick back up to 750ish the normal idle.
Now i've cleaned the AIV, as was recommended, and let me tell you that was dirty as hell, but that did clear up some acceleration hesitation, but not the rpm dropping. I was thinking it may be a vacuum leak somewhere or a sensor, but i check all normal visable hoses, and their fine.

And now hear i am i come to Zilvia to search and ask, so hopefully i've cleared this up alot better. So if you have an idea and want to give me some advice, then that would be greatly appreciated.
If your gunna sit there and tell me that i don't know how to drive standard or even a car for that matter, then i'd like you to stfu, cuz i was out driving when some of you were in elementary school running away from girls!

thanks

[91rusty240sx]

if you wanna simulate that rpm feeling, just keep your foot on the gas a lil longer... i know what your talking about cause my friends prelude does the same thing.

[240-porkchop-sx]

Originally Posted by 91rusty240sx

if you wanna simulate that rpm feeling, just keep your foot on the gas a lil longer... i know what your talking about cause my friends prelude does the same thing.

ok that will 'simulate' the feeling but solves nothing, i don't care about the feel...i know there is something wrong, the last thing i want to do is ride the clutch just to make this car feel like others.

Is there some kinda of idle sensor that is known to be faulty on s13's? I've already checked the injector resistance and maf sensor.

[DMCS14]

seems to me the supra has a heavier flywheel and the 240 has a light one heavy=more momentum(longer to slow down) lighter=less momentum(doesnt maintain speed for long)

[sykikchimp]

He just didn't explain his problem well in his first post.. NOT a stupid thread.. so stfu. :P

Check the IACV.. and your grounds. The IACV is located under the intake manifold near the back..
this hose:

leads to it.. spray a bunch of carb cleaner, or maybe seafoam in there to clean it out while the car is idling.

Bad grounds are very common on old 240's and cause the same kind of problem.

[hurleyboi514]

supra could have had a sticky throttle cable??

[240-porkchop-sx]

riteon chimp, i'll look at that tonite.
thanks a bunch for some useful info!

[Jhay]

Let me know if that works..porkchop..I dont have that problem right now but it would be nice to see if your problem gets fixed

[Yoshi]

ahhhh yes. Explained much better now, the initial post was very misleading.

After doing chimp's idea, it may also be good to reset the ecu... have you checked for it throwing any codes as it is right now?

[F3600]

My CA does that some time .. but only when i run it hard. Check for carbon buildup in all the litlle valve for idling.. goodluck

[idlafie]

[QUOTE=240-porkchop-sx]Ok i'll try to be more specific.
And all my vehicles have been stick for the 7 yrs i've legal to drive... so i know how to drive.

***HAHAHAHAHA.....EVERYBODY says that!!!.....subject to your OWN personal opinion!!!***

Thats not what i am trying to ask about.
Usually there will be some latency from when the clutch engages and the rpms drop, it could even be 0.5 of a second. BUT on my car there is no latency, it just drops like a bad habbit. Thats not such a big deal when i'm shifting up. Now when downshifting the engine rpm drops soon, so rather then engine sync'ing up a 1000-2000rpm, it drops lower then it should....again not really a big issue, i can live with it. BUT when coming to a stop sign, so i enage the clucth at about 1200-1500rpm to take the car out of gear, the rpms drop to like 300-400, then kick back up to 750ish the normal idle.

***Have you checked your EGR system??? EGR system engages during PARTIAL throttle operation, - You may have some carbon buildup in the EGR system which causes your EGR valve to stay open a little longer than normal causing the RPM to drop to the low 400's. ***

Now i've cleaned the AIV, as was recommended, and let me tell you that was dirty as hell, but that did clear up some acceleration hesitation, but not the rpm dropping. I was thinking it may be a vacuum leak somewhere or a sensor, but i check all normal visable hoses, and their fine.

***Yep...check your sensors, wiring, connectors AND your ground points....when it comes to RAPID RPM drop the AIV and EGR system usually play a role in this...it's all that damn carbon buildup. ***

And now hear i am i come to Zilvia to search and ask, so hopefully i've cleared this up alot better. So if you have an idea and want to give me some advice, then that would be greatly appreciated.

***See above.....for things to check....***

If your gunna sit there and tell me that i don't know how to drive standard or even a car for that matter, then i'd like you to stfu, cuz i was out driving when some of you were in elementary school running away from girls!

***HAHAAHAHAH....you 've ONLY been licensed to drive for 7 YEARS?? And you have an attitude that you are SUPERIOR?? HAHAHAHA....I was driving WAYYY THE HELL BEFORE YOU WERE EVEN A GLEEM IN YOUR FATHER"S EYE!!!...HAHAHAHA... ***

ID
...grampa mode!!!

PS:....you only set yourself up for the last one!!!...hahahaha...

[240-porkchop-sx]

LOL thanks for the input gramps, you speak with such wisdom! ...hehe

Well it's been awhile but i finally got the sea foam. I put some into my gas, oil, and sprayed some into my throttle body. From what i searched it's supposed to smoke like crazy! Well it didn't, i couldn't find the hose you labeled for me chimp, is it attached to the air intake hose? Alot of people recommend to suck it up the vacumm of the pcv valve. Know i know it's a PITA to get at, but is the vacumm line easiler accessible?
I haven't really noticed a difference yet. Is there any other vacumm line i can use instead?

thanks

[SHIFTrl240]

my car hangs at 2k when i shift it.. but thats cause i have an auto ecu

[Wei240]

so much reading, i just skimmed it,
basically try to clean bunch o crap as mentioned,
and see if you can drive someone elses 240 and compare...

[idlafie]

Originally Posted by 240-porkchop-sx

LOL thanks for the input gramps, you speak with such wisdom! ...hehe

Well it's been awhile but i finally got the sea foam. I put some into my gas, oil, and sprayed some into my throttle body. From what i searched it's supposed to smoke like crazy! Well it didn't, i couldn't find the hose you labeled for me chimp, is it attached to the air intake hose? Alot of people recommend to suck it up the vacumm of the pcv valve. Know i know it's a PITA to get at, but is the vacumm line easiler accessible?
I haven't really noticed a difference yet. Is there any other vacumm line i can use instead?

thanks

If you're trying to clean out the IAV valve, then just use the vacuum line that goes directly from the IAV to the brake booster. Disconnect it at the one way valve halfway between the IAV valve & the brake booster. Using that hose is a lot easier as you don't have to disconnect the intake to spray carb cleaner in the throttle body. Although spraying the interior of the throttle body with carb cleaner is always a good idea. One of the benefits about using the brake booster vacuum line is if you have a small funnel you can tip the vacuum line up & pour the sea foam directly into the line. Less mess.

Anyhow, FYI...ran across this seafoam instruction site...justs gives you a bit more info...

http://members.nuvox.net/~on.roz/cars/z28/seafoam.html

Good luck with everything....hope it fixes your idle drop.

ID

[kandyflip445]

The hose chimp pointed out is the bigger hose attached to the intake tube, I believe.