The Fred Posted October 2, 2006 Report Share Posted October 2, 2006 Some times I like to floor down the gas pedal up to around 40ish and then let go all at once and the car sort of says brrrrrrrr like all of my 89-91 Cads always have, What is that, engine braking because I let off before it can shift? See I have to let go around 40 in order to avoid a huge speeding ticket. I just wonder if it hurts anything getting off the gas all at once that way.. I figure it is just engine braking and that ought to be fine but I aint sure MerryChristmas Be a Capitalist or work for one. Work for a Capitalist or be one. MerryChristmas Link to comment Share on other sites More sharing options...
Cadillac Jim Posted October 3, 2006 Report Share Posted October 3, 2006 It's hard to tell definitively but it soulnds like the tranny is disengaging until the engine revs down to engage 3rd or even 4th. If you are at 40 in low (like I occasionally am after doing just what you say), it's near redline when you shut it off. If so, the "brrr... <fade to silence>" could be a mild crankshaft rate shake, which is normal for production engines. My original engine did that from birth and I never thought a thing of it. I've had other cars do that for years with no problems. My new Jasper doesn't do that. I have no idea whether It's better balance through luck of the draw or whether Jasper does a crank assembly balance. They tell me the the engine isn't blueprinted or balanced, just remanufactured to GM-supplied SAE specifications. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
JasonA Posted October 3, 2006 Report Share Posted October 3, 2006 I'm inclined to agree with Jim's first point. You're essentially closing the throttle when the engine has its most momentum, and the transmission is ready to bang into 2nd and continue pulling. I'm sure it doesn't harm anything, but I can't see it helping anything either, to break that momentum at the very point the transmission is trying to shift. For that reason, I never let off full throttle like that abruptly at redline. I either quickly but smoothly roll out so it'll shift, or keep it down until after the 1-2 shift. Mostly the first, though, because on an LD8 car, the 1-2 shift is somewhere around 50 mph, at redline! Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Cadillac Jim Posted October 3, 2006 Report Share Posted October 3, 2006 Yeah, I agree with JasonA. All the sudden shutoff does is quiet everything down so that you can tell the engine crankshaft balance is OK, then let it freewheel down to usable RPM for the speed and throttle setting. It's better to keep the tranny engaged. The torque converter is the best damper for crankshaft vibration modes; the front damper is just a backup for when the torque converter is disengaged and it's a poor substitute. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 3, 2006 Report Share Posted October 3, 2006 Well I figured I would comment on my experience with taking my foot off the gas fast. Last year a raced an Audi S4, and when I hit 90, I quickly took my foot off the gas (as I scared myself ) and a code set immediately. I got this code > P1108 - BARO to MAP Sensor Comparison Too High See this thread. http://caddyinfo.ipbhost.com/index.php?sho...458&hl=audi Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.