Computer Diagnostics and Tuning Technical discussion on diagnostics and programming of the F-body computers

Datamaster File inside, help me plz

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Old Sep 10, 2003 | 02:17 AM
  #1  
mycarisfasterthanyours's Avatar
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From: Prescott Valley, AZ
Datamaster File inside, help me plz

http://www.public.asu.edu/~rglennan/race%20car.uni

There it is. The car is the Camaro in the sig. It has been missing up higher in RPMs, but when I was logging this, it pulled pretty well to about 6000rpm. I have a feeling it has too much timing, but you guys probably know more than I do. Any help would be appreciated. Here is also a copy of my tunercat file.

http://www.public.asu.edu/~rglennan/pcmforless383.bin
Old Sep 10, 2003 | 09:51 AM
  #2  
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Here's a couple things I see right away... The injector size seems to be way off. Your long term fuel trim is always between +15 and +25%. This is also causing your engine to run pretty lean (look at the histogram while playing back).

You are getting quite a bit of spark retard, but that is most likely an effect of the lean condition.
Old Sep 10, 2003 | 02:39 PM
  #3  
mycarisfasterthanyours's Avatar
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I looked at my tunercat file, and the injector size seems to be right. It says it is 35.99 lbs/hr, and I have accel 36s. Anything else do you think I need to change or look at? Thanks for the help, I am really new to the tuning game.
Old Sep 10, 2003 | 07:41 PM
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From: so close I can taste it...
I think you can disable codes 83 and 84. Should shut your SES off.
And you do need to do something about you injector constant. Do you have an adjustable regulator, or still using the stock one? In either case, what fuel pressure are you running (at idle with the vacuum line disconnected from the regulator). Let me know and I'll recommend an injector constant that should work better.
You need to get your IAC counts up at idle. Shoot for something between 10 and 40. Not 0.
Timing map doesn't look too bad. Seems like quite a bit of timing at low rpm/low map though?
BLM cell boundaries need setup for your car too. Those values aren't going to get you hitting all of the fuel trim cells.
And I suspect that the miss you're feeling is knock retard, not a miss. You're maxing out the retard table at 5* so the PCM isn't able to pull anymore timing, and I'm sure it wants to.
Looks like you've got quite a bit of work to do.
Old Sep 10, 2003 | 08:27 PM
  #5  
mycarisfasterthanyours's Avatar
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I currently am running the stock regulator/fuel pump. I do not have a guage to verify the fuel pressure, but it should be close to whatever stock is. As far as adjusting the IAC, BLM Cell boundaries, and the max retard, what values do you recommend? Like I said I am really new at this stuff and trying to learn, Thanks for all the help.
Old Sep 11, 2003 | 07:10 PM
  #6  
Dan K's Avatar
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From: so close I can taste it...
Originally posted by mycarisfasterthanyours
I currently am running the stock regulator/fuel pump. I do not have a guage to verify the fuel pressure, but it should be close to whatever stock is. As far as adjusting the IAC, BLM Cell boundaries, and the max retard, what values do you recommend? Like I said I am really new at this stuff and trying to learn, Thanks for all the help.
Try an injector constant around 38. You might have to bump it up though. But that should be a good starting point.

Try and get the IAC counts to somewhere between 10 and 40 at a warm closed loop idle.

As far as the blm cells...it's really something you have to play with. Start with 1200, 1800, and 2400 for the blm rpm cell boundaries. And try 45, 60, 80 for the blm map cell boundaries.

I wouldn't recommend that anyone mess with any of the retard tables. They should be left to stock. On a correctly tuned car there should be no knock at all. Put them back to stock.

Try that to see what happens.
Old Sep 11, 2003 | 08:39 PM
  #7  
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Do you have an aftermarket TB or maybe you modified the IAC bypass in a stock TB like many guys have done to improve their idle quality? if not then you might have a possible vacuum leak... even if you did one of those things you might ahve a vacuum leak. my reasoning is that you have a lot of cubes with ported heads and a decent sized cam.. the IAC should be MAXING OUT at 160 counts or whatever it is, not 0! what this tells me is that air is finding its way in somewhere else other than past the IAC motor in your TB. This would also explain why your BLMs are so high.. unmetered air or air that doesnt pass thru the MAF sensor will increase BLMs like you are experiencing. raising your injector constant will raise your BLMs even higher which is the exact opposite of what you want so dont do that! i suggest doing a search for a possible vacuum leak and if none is found then lower your injector constant to around 30 to see where that gets ya.

Last edited by turbo_Z; Sep 11, 2003 at 08:44 PM.
Old Sep 11, 2003 | 09:05 PM
  #8  
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I have the closed throttle set screw turned out quite a bit. It is the only way that I could get it to idle without dying. Do I need to turn this back in and do some tuning work to get this thing to idle or what? Thanks for the help, I am going to mess around with it some tonight and see what I can do.
Old Sep 11, 2003 | 10:08 PM
  #9  
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From: so close I can taste it...
Originally posted by mycarisfasterthanyours
I have the closed throttle set screw turned out quite a bit. It is the only way that I could get it to idle without dying. Do I need to turn this back in and do some tuning work to get this thing to idle or what?
Yep. Unless you have a huge air leak somewhere like turbo_Z mentioned. Those high idle blm's should come down as you close off the throttle blades. That's a ton of air that's coming into the motor.
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