Hanging/Surging Rev

uncle_banjo · #1 (**permalink**) 10-20-09, 09:53 AM

Hey guys, im new to this forum! I have a 2006 Mustang GT with Thumper Cams, 4.10 Gears, C&L Racer intake, o/r X pipe, Borla's, and Exhaust cutouts. Ill get a picture up soon and stuff. But this post is about my car problem im having. My car has a surging/ hanging rev. It surges up to like 3k RPM when i shift, even when i shift at like 2k RPMs, it will go up all the way to 3k until i releas the clutch and put load on the engine. Also, I could be going like 3 mph - whereve, and rev it up with the clutch in, and it will stick at 3k-3100 RPMs until I come to a complete stop, then the RPMs will fall to normal. It will also stay at like 3k RPMs when i just let the gas off with no clutch involved, and it will stay there until i slow down with massive break. Its almost liek a cruise control. I have no idea, ive done research, but am unsure what the problem is. Also, I have had it dyno tuned, and when i first load the tune up, it runs great, then after a day or so, or a couple of turning on and off the car, it begins to stick, and progessivley gets worse the more and more I drive it. Is it a tune issue or a mechanical, or a combination of both. Any help is greatly appreciated and am happy to be joining this forum. Thanks in advance guys!

Also, I am not sure if this is the right place for this.

Informant736 · #2 (**permalink**) 10-20-09, 10:50 AM

It does sound like a tuning issue, like the dashpot values need to be adjusted. I would go back to the dyno shop and talk to them since they did the tune and like you said this is an issue that wasn't present initially and has gotten worse over time. So it might not have been present when the tuning was done and why no adjustments were made for it.

uncle_banjo · #3 (**permalink**) 10-20-09, 05:30 PM

Ok! I will definatley ask the tuner about the dashpot values and see if we cant get something! Thanks though man! What are the dashpot values though?

Informant736 · #4 (**permalink**) 10-20-09, 09:12 PM

the dashpot values are what the computer uses to determine how quickly the motor returns to its idle speed. And adjustments come into play when someones motor eithers hangs or flares when shifting in this case the motor needs to return to idle quicker; the other case is when the motor drops to idle to quick and the motor stalls out in this case the return speed needs to be slowed down.

Because of the cam this could be the issue but the tuner should be able to determine what exactly the issue is.

**walter** · #5 (**permalink**) 10-21-09, 01:04 AM

My revs also stuck to 2500-3000 when my first JLT intake broke causing me to run without a filter or proper air metering. Make sure your intake is secured and leak free, computer goes crazy if it can't read air properly and will do things like that.

uncle_banjo · #6 (**permalink**) 10-22-09, 06:22 PM

OK! Awesome! Thanks guys! I will look in to the dash pot values! That sounds like the problem. I will let my tuner know! And I will also check the the intake and see how secure it is! Thanks again! I will get a pic up here in a bit! LOL!