Improving WB Tune: Large difference in Min/Max + Suggested Values for TC+TF

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Originally Posted by 2002_z28_six_speed

2004 Yukon Denali.
Stock LQ4 bottom end. 6.0L engine
Precision Heads, 5.3L heads, stage 2.5
Texas Speed 224R cam, this is a 224/224 cam with .581 lift, 114 lsa
Kooks catted 1 3/4 headers with catted connection pipe.
Currently running factory muffler (wife says if it gets louder she will punch me in the face)
FAST LSXtr 102mm intake
stock intake tract and throttle body
LS2 corvette injectors.

At this point it rarely stalls but it chugs. Sometimes the RPMS fall down really low and after 2-3 seconds it will pick back up. This usually happens when slowing down. Sometimes the idle swings around.

I am planning on running through the CALC.VET thread today to see if that changes the fueling any and then try the RAFIG RAFPN again.

Attachment 18684

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Yes, I agree with statesman, I would start from stock again, work on VE and MAF (Calc.VET and Calc.MAFT)...

tell wifie that efficiency may cause louderness.

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Originally Posted by 2002_z28_six_speed

Seems drastic to just fix the hunting idle issue that remains at this point. BUT I am willing to try it. You guys know your s$#it. :)

I got the fuel injector data from a stock tune I got off Holden Crazy for a 2005 Corvette Automatic. I am in the process of comparing those sets of data now but it just takes time and the tables aren't 100% the same.

A torque converter will be installed at a later date. Factory tranny and TC at this time.

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It's not drastic at all. Random changes to your tune can be counter-productive... it can make it harder to find the cause of your problems.

You really should have a higher stall converter installed before tuning. The stock converter will put a bit more load on the engine at idle and cammed engines don't really like that very much.

I don't think that the injector data you found is very good. I've never seen an injector with voltage offset values that low. Bump up the entire voltage offset table by 0.3... that should help you get your MAF dialed in a bit better.

When you get your fueling properly dialed in, then you'll fix whatever hunting remains with your spark and air.

Statesman,

I wanted to let you know that you were right about the injector data. I started looking at it and it didnt make sense. At one point in time I was talking to a tuner (didn't end up helping me much). I actually have FAST 46LB LS2 style injectors. Part number 30462-8. The tuner said he wouldn't tune my vehicle because the FAST injectors sucked and they were just 2005 Corvette injectors. Somehow that stock data got into my tune and was forgotten about. I heard that the 2000 AMA corvette has injectors like this and could be used for the injector data but this hasn't been confirmed.


HMM. This could be a lot of the problem.


The converter will be installed at a later date but is coming. Living in the DC area I don't drive it much so I am taking my time ordering the parts.

statesman, good call on the injectors :cheers:

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Originally Posted by 2002_z28_six_speed

Statesman,

I wanted to let you know that you were right about the injector data. I started looking at it and it didnt make sense. At one point in time I was talking to a tuner (didn't end up helping me much). I actually have FAST 46LB LS2 style injectors. Part number 30462-8. The tuner said he wouldn't tune my vehicle because the FAST injectors sucked and they were just 2005 Corvette injectors. Somehow that stock data got into my tune and was forgotten about. I heard that the 2000 AMA corvette has injectors like this and could be used for the injector data but this hasn't been confirmed.


HMM. This could be a lot of the problem.

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Yeah, you really do need good injector data to get a good tune.

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Originally Posted by joecar

statesman, good call on the injectors :cheers:

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Thanks joecar :cheers:

Well my bike got a flat (and I didn't die!!) so I have been forced into working on this yet again. Reporting in that results are much better with the new (correct) injector data. Practically no stalling. There is some lugging when coming to a stop but not too bad. Hoping to have everything fixed soon.

That's great news. Are your wideband readings a bit tighter now?

Post your current tune and some logs so we can level set.

I would say that I could see .98 to 1.14 BEN in some cells while others are tighter.


One thing I noticed is the AFR will be great for awhile. 14.8. Then I get into traffic for 20+ minutes and the AFR will go to 15.5 or higher.
Still some random stalling in the parking lots.
I did notice that sometimes on restart the RPMs will jump up to over 2000 and creep down. If I put it in gear within 15 seconds of restart that will for sure kill it.
Sometimes when coming to a stop it will chug down to 400 RPM and pop back up. It doesn't seem any work to the Cracker table has helped so I will try to go back to stock cracker table BUT that does seem to make the vehicle cruise control at speeds over 50kph.
If I got WOT off the traffic light it will shudder for 5 seconds and then pick up.

{removed old tune files. see next post for updated files.}