No power under WOT

[frostchevelle]

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.

[frostchevelle]

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?

[lspwrd]

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

[frostchevelle]

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.

[lspwrd]

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

[frostchevelle1]

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.

[lspwrd]

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.

[frostchevelle1]

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

[lspwrd]

Thats close to OE temp settings, which is fine.

What about cam settings? Make any changes?

[frostchevelle1]

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.