03 cobra - SCT Tuning questions

[Brewster]

Can we post in this Forum using SCT software ? Working on an 03 cobra, 3.4L whipple, return fuel system, in tank pumps, BA5000 Maf in 123mm crusher intake, 80lb injectors ( customer had them decapped ).

Loaded up some value files to get me close and dialed in the maf using a mix of OL wideband and closed loop trims. Runs and starts good hot, it lights off good when it's cold but floods out within a few seconds of running and stalls the engine, if I pedal it to keep it running its super rich and pegs the wideband rich.

I noticed Adv3 auto scales injector values when loading up the maf value file, with that being said it looks like the low slope is pretty small now, could this be my cold start issue ? I've tried reducing the crank fuel, base fuel cold etc and nothing has changed the start and warm up fueling.

If the maf is big enough such as the ba5000 is it best to scale the file manually and not let it scale the injector data down so far?

Do I leave it where it all is and just raise up the low slope ?

[Brewster]

V12-HPX.mtf

(422.16 KiB) Downloaded 155 times

[decipha]

yep u can post here

Only an idiot would decap injectors. No doubt thats a major problem and not helping anything.

Congratulate him on his stupidity and tell him he needs to buy a new set of injectors.

The only way to dial in the injectors is to set the high slope to 30. Rape the maf and then adjust the low slope offset and breakpoint to dial in the lower range based on how far out it is from the known curve. Thats assuming the top end dials in properly and airflow through the maf is ideal.

No possible way to do that with obd2 logging is far too slow and inaccurate. You will need a quarterhorse.

[Brewster]

Yea seems to be a common trend lately for guys to get suckered into decapping the injectors and ruin the flow characterization from what I know. I do agree he should have new injectors installed but it's not in the budget atm. The injectors seem to be working and responding to changes fairly well but I'm sure it's not optimal by any means and or balanced correctly on all 8.

Do you have to change much when using value files, the auto scaling when I applied the BA5000 maf value file auto scaled all the fuel stuff to stay away from the airflow limits from my understanding. I was told to just leave the applied changes to slopes, break points etc alone and work in base cold tables etc to try and lean out the cold start issues.

Getting a QH these days is not so easy, I heard Core tuning still has some though. Hopefully someone talks Mr Moates into selling them the rights to that thing and keeps the legacy living on!

[decipha]

I dont use value files

the bigger problem is the fuel injector limit not the airmass

since there is no injector data u have to dial it in. again thats near impossible with obd2 logging

you cant dial in startup fuel til after you get the fuel dialed in

rights iasn the problem the chips are simply not available. xilinx is backordered 3 years so its impossible to make a quarterhorse til then. They have also tripled their prices so the cost is going to be prohibitive when that time comes as well.

[Brewster]

Yea I hear ya there on the SCT Stuff and value files. I wouldn't say I know enough yet to manually scale everything on my own and a QH for this guy is not in the budget. I guess I do have my own QH and a few chips left and could go that route cheap enough. Kind of sponsoring this one for him, he has a sick kid and lost his job, I need more training and knowledge on the platform so kind of a win win for both parties.

Stabilized warm fuel is dialed and working well, trims are looking good and wot fueling is pretty much bang on. Although I'm not a fan of these big maps in such a large diameter pipe for idle and low load stuff i think I got it ironed out fairly well so far the way the file is set up besides the rich as shit cold start lol.

I do get it with the chip shortage, we've felt it big time over the past few years especially in the Diesel world working on Ecm replacements with the L5P platforms.

[decipha]

You only need one QH.

Simply toss yours in there and dial it in.

No chip needed. He has the sct just write the final tune to the handheld.

/done

toss the qh in and post back a log ill take a look

[Brewster]

Well that is neat, I never even thought of that. Figured maybe the SCT stuff used some sort of proprietary way to deal with the data. I Def may try this, probably need to figure out how to set up the file but I'm guessing it would be all the usual stuff for fuel and maf. Not sure if you have a patch available for return fuel system or how to deal with those changes.

[decipha]

return fuel is simple just disable pump adaptives, literally change it from 1 to 0

[Brewster]

Ah ok, I'll get this all going and post back here next week. Appreciate ya !