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Thread: Sanity Check: AFR Issue & General Tune Review

  1. #11


    I assume you mean the left side is going leaner. This can be because of an exhaust leak in that side or you have an ignition misfire on that side. Check your spark plug wires on that side and make sure none of the wires are touching the headers, resulting in some arching. Andrew

  2. #12


    I pulled the plugs and they look good. I rechecked for leaks and nothing I can see. I repainted the exhaust because if a leak I'll see it on the paint and so far nothing. I picked up a new WBO2 sensor and I'll try it.

  3. #13


    #1 Cylinder is not firing. Ugh!!! Maybe bad injector since I replaced them or bad plug. I'll replace with another plug I got.

    BTW, it freaking hurts. I have the MSD HVC II Coil and testing distributor leads, one got sideways on me and now my arm twitches. OW!

  4. #14


    Guys need a little more guidance, I'm leaning to either bad configuration or a leaky set of injectors. I do not believe the recommendation for bigger injectors is incorrect as I can see that 600 HP engines need them and I'm 560-580 HP.

    Here's my compression ratio (before & after so no loss and after the heads have seated in they got mostly better):

    Here are my plugs (42.5 lb/hr Injectors):

    Here are my plugs (36 lb/hr Injectors):

    The car was down on performance and backfiring on runs. I've used AFIS injectors before, my 36 lb/hr ones were from them. 45 lb/hr part# is 8774201 and they are High Impedance and EV1.

    Before I the upgraded the injectors I enabled Injector Phasing, everything was running after the upgrade just chasing after the left bank issue and now it went all the way wrong.
    Last edited by czizza; 10-19-2020 at 06:25 AM.

  5. #15


    Did you change the Fuel Injector Information in the System ICF when you installed bigger injectors? Andrew

  6. #16
    Join Date
    Dec 2009


    Yeah, in Engine Parameters (System ICF).
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 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, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 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 M/T Street Comp tires.

  7. #17


    I appreciate all this help. Yes, I've made all of the changes and recommendations including the 1 msec minimum, the fixing the bottom two rows and the settings for the Injectors. I removed all of the injectors and will bring to someone to check them because I don't want to break anything or having anyone of them off. Here are my screenshots and a copy of my config "79Camaro409-254Cam-42LBsVE+IA-20201019"
    Here is the Engine Parameters:

    Here is the clearing of the two bottom rows and smoothing the graph:

    Here's the Injector Phasing:
    Attached Files Attached Files

  8. #18


    The VE% Table is still not great, but mostly in the rarely used areas. Whenever I see a big difference between banks, my "go to" is an exhaust leak. Andrew

  9. #19


    I rechecked with the car on the lift and a spray bottle, very light tissue and nothing I can find. It was not jumping that bad until the injectors change. They were just out of sync meaning my right bank was 13.2 and my left was 14 AFR. On deceleration the left side would hit 20 AFR.

  10. #20


    Quote Originally Posted by czizza View Post
    ...On deceleration the left side would hit 20 AFR.
    My money is still on an exhaust leak. Andrew

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