SD2/Powerlogger Pro general discussion

[TurboDave]

Let me know when to pull the trigger. You know what I mean about the AFR Correction graph, right? That funny sawtooth my disconcert a few at first.

 

[TurboBob]

I will. The correction-factor in narrowband mode looks virtually identical to the integrator when running a stock style chip. Most guys aren't used to seeing it though..

Bob

 

[huntsg]

Looking for some help yet again. I'm not sure if I did something to the tune, but I can't imagine what. This has been going on for awhile now and happens fairly consistently. When I get on it and the engine is going up the RPM curve all of a sudden the RPMs drop about 800- 1000 and the car bucks. You can see it in frame 4274 in the attached log. Any ideas what could be happening?

 

[TurboTdr3.8]

I'm not sure if I did something to the tune, but I can't imagine what.

What did you do to get to this point ?

 

[huntsg]

Just worked the VE and AFR tables.

 

[TurboTdr3.8]

I noticed you have your car tuned to the leaner side as the correction has to add fuel , I tuned my car the other way as to take fuel out instead of adding , you may be crossing over the line too far from what your car likes or needs

 

[huntsg]

Where in the tune are you looking?

 

[TurboDave]

Leaner? Maybe during cruise, but look at his WOT pull!! It's showing 10.0:1 and then some even though the target AFR is set to 10.4 in that area (why so rich???).
Cell 8 is set to 134, and late in that WOT pull the AfC is truggling to pull fuel to get to the target.

But I don't see what's causing that rpm drop. Could it possibly be so rich as to be rich mis fire? AFR graph only goes as low as 10, which is that wideband's lower limit. It very well could be even significantly richer than that!

 

[TurboTdr3.8]

This is a area I was referring to on that given frame , I was just giving you my OP .

 

[TT/Ameasap]

I am having an off idle stumble problem while in park. I set the fuel composition to 180 from the 166 and my AFR at idle is 13.0-13.5 vs 15.0-15.5
So that was fixed rather nicely, but ever since swapping to this chip, I have had an off idle stumble. If I jab the throttle in park, car hesitates really bad for a second and then catches. During this, I notice the WB going to 17 or more for that same time. I dont have any logs...sorry. Just thought I could add fuel and correct it.
The last 4 TT chips including SD chips never had this problem.

Any ideas, lemme know

 

[TurboBob]

try increasing the injector offset, what is it set to at the moment?

B

 

["Reaper"]

I am having an off idle stumble problem while in park. I set the fuel composition to 180 from the 166 and my AFR at idle is 13.0-13.5 vs 15.0-15.5
So that was fixed rather nicely, but ever since swapping to this chip, I have had an off idle stumble. If I jab the throttle in park, car hesitates really bad for a second and then catches. During this, I notice the WB going to 17 or more for that same time. I dont have any logs...sorry. Just thought I could add fuel and correct it.
The last 4 TT chips including SD chips never had this problem.

Any ideas, lemme know

Parameter 12 is the tip in fuel parameter for off Idle response. Try adding fuel there. Mine is set to 205. Has a lot to do with how big of cam your running. Don't get hung up on the #'s yours May take more or lees to fix it. Remember it's what the car likes and wants not what you want.

 

[TurboTdr3.8]

Parameter 12 - Acceleration Enrichment Fuel
This number is a fuel trim with 128 being “the middle” or 0%. Higher than 128 adds fuel.
The adjustment modifies the AE fuel. AE fuel is only applied during “tip in”, while the throttle is
moving. So if you have a tip-in stumble right when you move the throttle, you can try adjusting this
to improve response. I would go at least 10 numbers at a time to see a difference. Don’t be afraid to
go very high (255) or very low to see the results. This can be adjusted by sitting in the driveway, car
idling, and stab the throttle a little bit to hear any stumbles. Do not place too much emphasis on the
A/F reading as it’s typically to see a small lean spike, then a rich dip afterwards. Just make sure it
responds well and sounds smooth. Sometimes it helps to not stab and release, but to stab and let
the motor accelerate up a bit, then let off, to avoid false rich readings.

 

[TT/Ameasap]

Bob do you reccomend that I change back to 166 in the fuel comp. and try the injector offset?

Reaper, I just found my SD2 book and you are correct. I will adjust param 12 for the off idle stumble. Thanks!

 

["Reaper"]

Bob do you reccomend that I change back to 166 in the fuel comp. and try the injector offset?

Reaper, I just found my SD2 book and you are correct. I will adjust param 12 for the off idle stumble. Thanks!

NP hope that helps.

 

[TurboDave]

Ya, give parameter 12 a bump. I have mine pushed up to 230.

 

[TT/Ameasap]

Like a top fuel dragster at 250. Thanks guys!

 

[TurboTdr3.8]

Like a top fuel dragster at 250. Thanks guys!

That is nice to have adjustment when you need it with the SD2 , life is good .

 

[TurboBob]

the tip in enrichment interacts with the injector offset. if you adjust one, you may need to adjust the other.

Bob

 

[TurboDave]

I wish I understood the injector offset better.

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