[Pure Lude]

what could cause my rpms to rise after i left off the throttle and push in the clutch?

if i let off the throttle wait a second, and then push in the clutch things are ok. If i want to shift fast, then i see the rpms jump then fall. In low rpm high gear pulls, i can get the rpms to jump a good 500rpms then fall.

I tried shifting fast (not at redline) and i saw the rpms jump up about 300rpms...

dunno whats wrong...something in the transmission no doubt.

Tim

 

[88lude]

sounds like you are doing it a little too fast and the throttle is still pressed in a tad bit when you hit the clutch which would make the RPMs rev just a little. at least that is IMO

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Benson

 

[Pure Lude]

it can't be that......this happened recently after the turbo install...i've been driving this car for two years now, and i've been redlining it long ago with no such problems.

i was thinking that maybe my throttle cable is funky, but i can rev the engine in neutral fine, it goes up and comes down normally...



[This message has been edited by Pure Lude (edited March 30, 2001).]

 

[Guest]

<font face="Verdana, Arial" size="2">Originally posted by 88lude:
sounds like you are doing it a little too fast and the throttle is still pressed in a tad bit when you hit the clutch which would make the RPMs rev just a little. at least that is IMO
</font>

I agree with that idea.

How could it be the transmission?

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Billy
North Texas Prelude Owners Group
www.ntpog.org

 

[pter]

<font face="Verdana, Arial" size="2">Originally posted by Pure Lude:
this happened recently after the turbo install...
</font>

This may be waayyyy off the mark, but maybe it's a result of the turbo?

 

[floundericiousFL]

my thoughts:

It sounds like what you've got is a very slight lag-response on your fuel system....

What I mean is this: When you lift throttle and hit the clutch, there's still a certain fuel charge in your intake passages....that will usually, when you lift throttle, keep the rpms up for a second and THEN let the engine begin to slow down (yes, this happens on my BONE STOCK 2000)....

SO....while the amount of air going in has decreased there's still a certain amount of fuel going into the engine for a few tenths of a second, still generating extra power and causing the rpms to jump a little before engine braking takes over...

possible cause:
Your TB is shutting while you're still getting a large amount of fuel in...this would make the engine run richer for a second and could cause it to rev a little more (don't know if that's true or not, just throwing an idea out)

That sounds like one possibility to me...hope this helps!

The idea mentioned farther up the post, where it was suggested that maybe you're not totally off the gas by the time you disengage the transmission, sounds very reasonable too!

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2000 Ficus Green Prelude - Powered by WAAAAAAAAH PPPSSSHSHHHH

What stands between a Prelude Driver and an ear to ear grin? About 5500 RPMs!

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[This message has been edited by floundericiousFL (edited March 30, 2001).]

 

[Pure Lude]

i know i'm off the gas...

 

[ImSLeEpY]

i think it's the turbo, cuz its prolly still pushing in air a lil after you let off yer gas. you got a blow off valve/does it let off immediately after you let off gas or there is a lil lag. if ther is a lag, thats prolly it

 

[Darth Luder]

Yeah, your throttle body definately will not just instantaneously stop and your rpms will not just instantaneously stop going as fast when you let off. You have all this stored energy in the system, not to mention some cylinders still firing. Then you push in the clutch, taking a large load off of the engine, so of course your rpms are going to go up and then fall back down. Hope this helps.

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If you only knew the power of the Lude...
'98 Red Base Prelude
"Straights are for fast cars. Turns are for fast drivers." - SCCA Solo2
AEM CAI, APEX-i VAFC, Neuspeed Ft Up Strut Bar, 28 mm Neuspeed RR Sway Bar, Neuspeed Sport Springs, Koni Yellows, and SH RR Deck installed. Shock knock cure done. Installing Quaife ATB Differential.

 

[Pure Lude]

ok, say when you are drag racing, you have to shift fast. Let off the throttle, shift, etc...if you shift at redline, then all you guys are saying that you have hit the redline because of the load? never happened to me before...

Tim