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Thread: No power under WOT

  1. #1

    Default No power under WOT

    I have got my car running and it idles great and drives nice and smooth. The issue I have is under full throttle it just flat falls on its face. Its a basically stock 2002 5.3 with a cam and valve springs. Cam specs

    Lift .613 .617

    Duration @ .006 277 281

    valave timing @.050 INT 4 42 EXH 52 1-

    109 centerline

    Duration @ .050 227 231

    Lobe lift .361 .363

    Lobe sep 113

    Rocker arms 1.70

    This was a custom speced cam for my future turbo setup. The injectors are factory for now, all sensors are factory. At idle I'm running 21* timing and under part throttle is runs clear up to 38*timing under full I havnt been able to look at it I don't want to hurt the engine.

  2. #2

    Default No power under WOT

    Just curious as to what it takes to get a reply from MSD. I have emailed and posted on here with no answer from either. Is there somewhere else I need to be posting my questions?

  3. #3

    Default No power under WOT

    SSounds like a possible fuel supply issue. Need details on fuel system and settings.

  4. #4

    Default No power under WOT

    Fuel system is a speedmaster pump the larger pump that looks like a A1000. Goes through the fuel rails and into an aeromotive bypass regulator. Runs at 58psi idle and goes up to 60ish during part and alittle above that during full throttle. I did check timing and its running at up to 36 to 38 at part throttle and backs all the way to 16 under full throttle. Basically stock truck engine besides the cam and springs. 12.0 full throttle AFR idle is around 14.9.

  5. #5

    Default No power under WOT

    AFR looks good. What cam setting did you use? Stock,mild,performance?

  6. #6

    Default No power under WOT

    Had to reregister for some reason. Right now I have it set to mild, I wasn't sure which to set it at cause it is right on the edge of the performance setting.

  7. #7

    Default No power under WOT

    Try stock to see if that helps,our cams are very close and mine falls more in the mild range as well but drivability and performance was waaay better on stock. The cam settings change the VE tables they have programmed in the ecu. Remember, these engines are VERY efficient for a pushrod V8, thats why they make the power they do over a traditional sbc. Try stock, let it get to operating temp so it can relearn and let me know how it is.

    BTW, what temp is it getting to? Make sure you don't overcool it either or it will never learn and run correctly.

  8. #8

    Default No power under WOT

    I have the fan coming on at 195 and it stays around the 200 to 190 range.

  9. #9

    Default No power under WOT

    Thats close to OE temp settings, which is fine.

    What about cam settings? Make any changes?

  10. #10

    Default No power under WOT

    I have not made any changes yet, the weather has turned bad and we had ice on the roads. What should total timing be under wide open throttle? I will get it out later this week and run it alittle. It was running at 16 WOT without any advance added to it cam setting mild. I did get a chance to add timing under WOT by 7 degrees but didn't seem to help at all. I did not get a chance yet to try it with the stock cam setting yet. It also seemed to have fall on its face around 5k rpm.

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