Engine Management eCtune , Crome , AFC , FMU , Zdyne , Hondata , EMS , TE , Uberdata Anything to control your fuel, spark needs!

lurching on and off throttle with vafc / 440s

Old 10-15-2003, 05:51 PM
  #1  
1.0 BAR
Thread Starter
 
Join Date: Sep 2003
Posts: 453
Default lurching on and off throttle with vafc / 440s

Know what happens in a manual when you are rolling at 15mph in 1st and you let off the car? Then what happens when you get right back on it? The car lurches forward, then back. I just installed a set of RC440 injectors (had the VAFC installed for about a week) and set it at -40 across the board and my car started doing that whenever I let on or off the gas. If the throttle goes all the way down to zero, and the pressure goes to a full vacuum it lurches a little bit, then when I press the gas, no matter how gently, from around 0%throttle and approx -12.0 psi it lurches the other way. This is not affected by speed or rpm, altho when the engine isn't producing much torque it isn't as noticeable. I didn't have this problem before I installed the injectors. Has anyone else experienced this? Know a fix? It is annoying!
d16tuner is offline  
Old 10-15-2003, 07:02 PM
  #2  
3.0 BAR
 
Join Date: Mar 2003
Posts: 21,494
Default Re:hesitation from -12psi / 0%throttle

Check the injectors? Are you sure they are good?
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
Dr.Boost is offline  
Old 10-15-2003, 08:07 PM
  #3  
1.0 BAR
Thread Starter
 
Join Date: Sep 2003
Posts: 453
Default Re:hesitation from -12psi / 0%throttle

I'm not sure how to tell - check them how? They seem fine. If they weren't putting out enough fuel, it seems like I'd have problems at higher rpms as well and not just when first pressing the throttle pedal. I've thought about running injector cleaner thru it, this just feels like an electronics problem more than anything, but I really can't rule anything out. That is why I was wondering if anyone else running an afc experienced anything similar.
d16tuner is offline  
Old 10-15-2003, 08:26 PM
  #4  
3.0 BAR
 
Join Date: Feb 2003
Posts: 9,089
Default Re:hesitation from -12psi / 0%throttle

sounds like you've got too much fuel..

non turbo I'm assuming?

450cc - 46% = 243cc
440cc - 40% = 264cc

440cc - 44% = 246cc
440cc - 45% = 242cc


try -44 or -45 ?
88crxSi is offline  
Old 10-15-2003, 11:11 PM
  #5  
1.0 BAR
Thread Starter
 
Join Date: Sep 2003
Posts: 453
Default Re:hesitation from -12psi / 0%throttle

I tried it for awhile at -45 and it didn't seem to make a difference. I didn't keep it there long since I haven't messed with the timing any, and it was making some uncomfortable noises. I'll try it again tomorrow when I have time to mess with it some more.
d16tuner is offline  
Old 10-16-2003, 12:32 AM
  #6  
0.5 BAR
 
Join Date: May 2003
Posts: 193
Default Re:hesitation from -12psi / 0%throttle

mine did the same thing with 450cc, vafc and -46 accros the board.
rextec is offline  
Old 10-16-2003, 01:14 AM
  #7  
1.0 BAR
 
Join Date: Jan 2003
Posts: 438
Default Re:hesitation from -12psi / 0%throttle

no dude everybody is steering you wrong. It's only real bad when you lean it out TOO much.

set your crossover to 70%/71%, set your low throttle settings a -36 across the board, and set your high throttle to -38 across the board.

It's a great baseline, used it on three different cars. I've fucked around for hours. It's one of the better one's i've come up with. Too much fuel will cause a bog, too little fuel causes the jerk. -36 is jusssst right!
Johnyquest is offline  
Old 10-16-2003, 05:51 PM
  #8  
1.5 BAR
 
Join Date: Jun 2003
Posts: 1,145
Default Re:hesitation from -12psi / 0%throttle

no dude everybody is steering you wrong. It's only real bad when you lean it out TOO much.

set your crossover to 70%/71%, set your low throttle settings a -36 across the board, and set your high throttle to -38 across the board.

It's a great baseline, used it on three different cars. I've fucked around for hours. It's one of the better one's i've come up with. Too much fuel will cause a bog, too little fuel causes the jerk. -36 is jusssst right!



Is this for N/A? or Boosted?
civicvtecb16a is offline  
Old 10-17-2003, 12:27 AM
  #9  
1.0 BAR
Thread Starter
 
Join Date: Sep 2003
Posts: 453
Default Re:hesitation from -12psi / 0%throttle

NA for now. I haven't got my piping, and I'm not totally comfortable installing the turbo until I've got the kinks worked out anyway.

So you are saying to set the low throttle to 70% and high to 71% (right now they are at factory 10 and 50%) and set the fuel subtract to 36 and 38? I should be rich already, that seems REALLY rich NA, but I guess it is worth a try. Unless of course you were assuming I was boosted already... I'll still try it since it would always occur off boost and so it shouldn't matter.

BTW, I was messing around today and discovered that the throttle doesn't have to go all the way down to 0% and the pressure doesn't have to go all the way down to -12psi. About -11psi and 3-5% will do it to if there is no load on the engine whatsoever. I sure hope I can figure out for sure what is causing it!
d16tuner is offline  
Old 10-17-2003, 08:05 AM
  #10  
3.0 BAR
 
Join Date: Feb 2003
Posts: 9,089
Default Re:lurching on and off throttle with vafc / 440s

im guessing its because of your throttle settings. Try changing them to 70/71 and leave everything else the same.
88crxSi is offline  

Thread Tools
Search this Thread
Quick Reply: lurching on and off throttle with vafc / 440s


Contact Us - Sitemap - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.