10-18-2006, 07:59 AM
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#1
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Registered User
Join Date: Aug 2006
Location: Kenner, LA
Posts: 23
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knocking or popping sound at start up
Every so often I get a popping sound from the exhaust when I start the car and accelerate. Almost like a hesitation. What I have to do is accelerate hard a couple of time and it goes away. Any ideas???
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10-18-2006, 09:22 AM
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#2
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Guest
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Jteixidor, please list your:
Year
Mileage
Engine/Model
And any codes if you have them
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10-18-2006, 12:29 PM
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#3
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Registered User
Join Date: Aug 2006
Location: Kenner, LA
Posts: 23
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Car
2001 Porsche Boxster
31K
just recently did the 30K service with Porsche
2.7 engine and I dont get any lights on the dash (if that is what you mean by codes)
Joshua
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10-23-2006, 09:59 AM
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#4
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Registered User
Join Date: Aug 2006
Location: Kenner, LA
Posts: 23
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Anyone have this happen????
__________________
Joshua
2001 Boxster
2.7 , 30K miles
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10-23-2006, 10:39 AM
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#5
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Registered User
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
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Hi,
Is it Knocking or Popping? Two completely different things.
Knocking would indicate something mechanical, such as an engine internal or even a loose exhaust component.
Popping would seem to indicate a problem with the A/F Mixture causing unburnt fuel to ignite in the exhaust, this could be either a Rich or Lean condition caused by anything from a bad MAF to an Air or Vacuum leak. No Codes?...
Happy Motoring!... Jim'99
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10-23-2006, 11:13 AM
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#6
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Registered User
Join Date: Aug 2006
Location: Kenner, LA
Posts: 23
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Not sure
Quote:
Originally Posted by MNBoxster
Hi,
Is it Knocking or Popping? Two completely different things.
Knocking would indicate something mechanical, such as an engine internal or even a loose exhaust component.
Popping would seem to indicate a problem with the A/F Mixture causing unburnt fuel to ignite in the exhaust, this could be either a Rich or Lean condition caused by anything from a bad MAF to an Air or Vacuum leak. No Codes?...
Happy Motoring!... Jim'99
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Not really sure, Sounds more like a pop in the exhaust. If you mean lights on the dash by codes, I dont have any lights coming on. Any ideas?
Joshua
__________________
Joshua
2001 Boxster
2.7 , 30K miles
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07-24-2007, 07:09 AM
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#7
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Registered User
Join Date: Jun 2005
Location: Rosemead, CA
Posts: 216
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Quote:
Originally Posted by jteixidor
Not really sure, Sounds more like a pop in the exhaust. If you mean lights on the dash by codes, I dont have any lights coming on. Any ideas?
Joshua
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Did you ever find out what the problem was or is?
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07-25-2007, 10:42 AM
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#8
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Registered User
Join Date: Jun 2006
Location: Huntington Beach CA
Posts: 21
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I think I know what you mean and mine does this from time to time. (2001 S, 6 speed.)
I'd say it's more like an air "burping" or "gulping" sound, which could be described as a muted/muffled/soft popping or knocking.
I've always assumed it was just some normal intake noise -- never noticed any problem.
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10-29-2007, 08:26 PM
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#9
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Registered User
Join Date: Mar 2007
Location: Redmond Washington
Posts: 6
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popping and hesitation
Mostly when cold, if I have to stop in traffic right after starting, then tremendous hesitation. Sometimes 1-2 seconds before engine speeds up. Then hesitation at 2800 RPM and it lasts for a day. Overnight, restart and drive and about 5-10 miles later all is okay again until the next time. No codes and no pending codes. 2001 5 speed. New MAP, new air oil separator and rubber boot.
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10-30-2007, 03:14 AM
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#10
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Registered User
Join Date: Jul 2006
Location: Virginia
Posts: 916
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"Every so often I get a popping sound from the exhaust when I start the car and accelerate. Almost like a hesitation. What I have to do is accelerate hard a couple of time and it goes away."
Mine does not really pop, but you can hear the exhaust gurggle, not when I accererate, but when I let off the gas. It does sound like unburnt fuel igniting, but just checked my mixture last week and its right on the money. I suspect it is just my exhaust system allowing you to hear more of what is going on. Anyone else with headers 100-cell cats and a high-flow muffler hear that sort of thing?
Ed
__________________
My Car Webpage
2000 2.7L Boxster 102K; TTP intake, headers, high-flow cats; Dansk high-flow muffler; Autothority ECU chip; TechnoTorque 2; Bilstein coilovers; Racing Dynamics strut brace; stress-bar suspension kit; Aasco lightweight flywheel, B&M short shiftkit; 18" wheels; spare tire delete; OEM GT3 seats; JL audio speakers and subwoofer; Alpine PDX-5/PDX-2 amps; Kenwood DNX8120 CD/DVD/Nav; litronics, deambered
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10-30-2007, 05:09 AM
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#11
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Registered User
Join Date: Nov 2006
Location: In the garage...
Posts: 1,702
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Quote:
Originally Posted by edevlin
Mine does not really pop, but you can hear the exhaust gurggle, not when I accererate, but when I let off the gas. It does sound like unburnt fuel igniting, but just checked my mixture last week and its right on the money.
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Ed-
I have a stock '99 w/ the 2.5 monster but had a similar gurgle sound when I let off . It went away when I replaced my AOS which I had a feeling was going bad. Not sure when/if you last inspected your AOS, but I'd pull the j-tube and also inspect your throttle body for more than a light misting of oil. Otherwise, you could be right and it might just be your headers.
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10-30-2007, 03:51 PM
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#12
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Registered User
Join Date: Aug 2007
Location: New Jersey
Posts: 691
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Quote:
Originally Posted by edevlin
"Every so often I get a popping sound from the exhaust when I start the car and accelerate. Almost like a hesitation. What I have to do is accelerate hard a couple of time and it goes away."
Mine does not really pop, but you can hear the exhaust gurggle, not when I accererate, but when I let off the gas. It does sound like unburnt fuel igniting, but just checked my mixture last week and its right on the money.
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Ed, my '02 S did this too. I checked the AOS, and it was fine. It kept getting worse until I ran a bottle of Techron thru... Amazingly easy fix, car runs like new now. Gas mileage dramatically improved too. My car is stock.
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10-30-2007, 04:46 PM
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#13
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Registered User
Join Date: Apr 2006
Location: Chicago
Posts: 1,518
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Ok guys, what is the deal with Techron ?
Does this stuff really work, or is it snake oil ?
If it is worthwhile, where can I get it ( I don't see any Chevron stations listed in Illinois on their website ) ?
Thanks,
Nick
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10-30-2007, 04:48 PM
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#14
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Guest
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Quote:
Originally Posted by NickCats
Ok guys, what is the deal with Techron ?
Does this stuff really work, or is it snake oil ?
If it is worthwhile, where can I get it ( I don't see any Chevron stations listed in Illinois on their website ) ?
Thanks,
Nick
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Nick, I have used it. About once per year. You can buy at any of the better auto parts stores. It's a black bottle. They have it pre-measured for 12 gallons and 20. I use the big one. Cost about $11.
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11-02-2007, 07:45 AM
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#15
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Registered User
Join Date: Oct 2007
Location: Washington DC
Posts: 88
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Techron is good.. I've seen the results first hand tearing down a 911 motor that I ran Techron through with every oil change.
HOWEVER.. I have seen a more direct improvement in my Jeep and my 951 using the Lucas products. I highly recommend the Lucas fuel additive ( http://lucasoil.hodgsoncorp.com/lucas_fuel_treatment.htm
It solved a bouncing idle issue in my Jeep, and marginally improved throttle response in the Boxster.
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