Page 2 of 5 FirstFirst 1234 ... LastLast
Results 11 to 20 of 47

Thread: Exhaust pops under acceleration.

  1. #11
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,568

    Default

    Quote Originally Posted by another69 View Post
    Did a datalog today, and nothing really stands out, except maybe the ignition timing which may not be right on for an LS3. Both banks have very similar AFR readings, low 12s when the exhaust is backfiring under load. Only on the passenger side. Can an exhaust change really do this?
    Ah, now it's a "backfire" under load, not just a pop. The engine must be misfiring intermittently, and unburnt fuel in the offending cylinder becomes the backfire in the exhaust. Gary
    Regards, Gary

  2. #12

    Default

    Sorry if I don't have the terminology correct. It's popping through the passenger bank exhaust that I'm calling a backfire. No noticeable drop in power or anything, and pretty consistent. Could ignition timing cause this on just 1 bank? Maybe I'll swap ignition components from 1 side to the other.

  3. #13
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,568

    Default

    Do you have side pipes on this? With no crossover, the exhaust will sound different from one side to the other because of the firing order. For me, a backfire is loud, where a popping sound would be not as loud, agree? Gary
    Regards, Gary

  4. #14

    Default

    Agree, in that case it's more of a popping. Never in 1st gear, but every time in 2nd under hard acceleration. No side pipes, just full 2-1/2" exhaust leaves the 1-7/8" headers separately.

  5. #15
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,568

    Default

    OK, how do you know it's the passenger side? Why not add an X-pipe in the middle? It will make more power, and not have as much "crackle"? Gary
    Regards, Gary

  6. #16

    Default

    I have a torque arm suspension, so there's very little room for any kind of exhaust crossover. You can clearly tell that it's coming from the passenger side if you're in the car. Passengers can hear it too, sounds like something is wrong, makes me back off the throttle.

  7. #17
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,903

    Default

    If the Base Fuel Table is well tuned, have you tried running it in Open Loop? Also, do you have a copy of a "known to be good" Global File? I wonder if the Learn Table indicates a significant change in that area:
    http://forums.holley.com/showthread....1842#post61842 (Learn Table - Diagnostic/Troubleshooting Tool)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  8. #18

    Default

    That's a good point Danny. I'll try the last known to be known good Global File. I save them every now & then. I'll also check the Learn Table again.

  9. #19
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,903

    Default

    Yeah, the tune might reveal a clue to the issue (like maybe an exhaust leak upstream of the WBO2 sensor).
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  10. #20
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,568

    Default

    I can't see an exhaust system change causing this issue. But also, why would a tuning issue cause this? Have you had the spark plugs out for inspection?
    Regards, Gary

Page 2 of 5 FirstFirst 1234 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us