SCT PRP Support

Wicked46

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It's been a little challenging these days to get any support from the SCT pro racer forums. I was hoping to reach out to the SVT community and see if anyone with the SCT Pro Racer Package can give me some advice.

Short story on the car:

2003 Cobra AMZ2 processor, 10.5:1 Teksid engine, Bullet cams, 1 7/8 exhaust, e85, TVS, TH400 transmission


1st issue Im having is with the car HOT starting. Do I add fuel during cranking or take away?

2nd issue is with the idle. Car is set up to idle at 800 RPM which it will do just fine. When I “blip” the throttle, as the RPM’s come down, it will usually fall below 800 RPM and want to stall. This also happens when I put the car in gear to drive. It will sometimes stall when doing this. I’ve played around with dashpot and idle spark gain and got it a little better but I’m still not there yet. Any tips to get this thing to idle better?


I’ve attached some datalogs. Feel free to critique them and offer some advice. Also ***note*** I tune in closed loop with adaptive off and monitor the STFT’s. I know I’ll get a ton of opinions on this as some people say the best way to tune the car is in open loop. I’ve just always done it this way.
 

01yellercobra

AKA slo984now
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I had a hot start issue with my old set up. If you hold the throttle on the floor will it start quicker? Mine would, so I took fuel away. I basically divided the old injectors by the new injectors and took that much out of crank fuel. I had to tweak it a little after that, but it got rid of my hot start issue.

I've never dealt with an auto. What about the idle integrator? How close to 0 is it?
 

cj428mach

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My car needs extra iac cranking duty cycle to start well on E85. I say add an extra 10% and see what happens.

As for the idle, I'd suggest looking through the tune, there are actually several different scalars that are based on your idle settings so make sure they're adjusted besides just increasing idle rpm. Rather than deal with it I just left my car set to idle at stock RPM so I wouldn't have to worry about needing to tweak anything else.

You might try going over to www.efidynotuning.com and see if decipha can give you some info on setting up "mechanical" idle in the tune. I know he has instructions for doing this on older ecms.
 

Wicked46

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I figured it out. For those experiencing similar issues, logging your isc duty cycle helps a lot. I was in the 60 percent DC with the car up to temperature and at a steady idle. I had to adjust the throttle body blade quite a bit and play around with the Isc neutral idle air scalar in the tune.

I'm now in the high 20% isc duty cycle and the car idles like a dream. It no longer stalls when I "blip" the throttle, timing at idle is WAY more stable and the car hot starts way easier.
 

ctgreddy

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I figured it out. For those experiencing similar issues, logging your isc duty cycle helps a lot. I was in the 60 percent DC with the car up to temperature and at a steady idle. I had to adjust the throttle body blade quite a bit and play around with the Isc neutral idle air scalar in the tune.

I'm now in the high 20% isc duty cycle and the car idles like a dream. It no longer stalls when I "blip" the throttle, timing at idle is WAY more stable and the car hot starts way easier.

At that point did you have to adjust the blade open? I'm assuming so to take away duty cycle from the isc.

Some good info in this thread!
 

Wicked46

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At that point did you have to adjust the blade open? I'm assuming so to take away duty cycle from the isc.

Some good info in this thread!

Yes, I brought the duty cycle down to a reasonable range 1st. Then made changes to the ISC Neutral Idle table. I'm glad I fixed both of my issues. I wasn't sure what to do about the hot start issue I was having. This took care of both!
 

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