timing help
03-04-2007, 10:42 AM
#1
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timing help we put my car on the dyno yesterday and i only put down 320/337 my afr is 14.4 and its dumping fuel above 5300rpms. i data logged some stuff on the way home with my xcaliber and it only has about 29 degrees of timing over 5200 rpms what would cause it to pull timing up high? im going back this week to get it tuned to fix it but what would cause it?
03-04-2007, 10:55 AM
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Couple of questions: Are you indicating your AFR was 14.4 on the dyno pull? If so, that is a tad lean IMO. You might want to aim for something more along the lines of 12.8:1. I don't think you you'll get too many pulls out of her at 14.4. Was the timing on the dyno 29*? If so, that may be what the engine needs. Is the tune commanding more? Knock would be the first place to look, but then there are numerous other timing offset tables including ECT and IAT adjustments.
03-04-2007, 12:40 PM
#3
Definatly needs more fuel at WOT. Are you using the stock injectors? What is your fuel pressure at wot? 14.4 is definatly too lean.
Maybe your Maf is messed up or dirty also? Did they unplug the Maf and try another run to see if it was the cause of the issue?
As for timing, 27-29 degrees on that engine year is normal.
Did i make the Excalibrator for you?
If so, I would send it back asap to Add in more fuel for the engine.
Maybe your Maf is messed up or dirty also? Did they unplug the Maf and try another run to see if it was the cause of the issue?
As for timing, 27-29 degrees on that engine year is normal.
Did i make the Excalibrator for you?
If so, I would send it back asap to Add in more fuel for the engine.
03-04-2007, 01:54 PM
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yes you made my excaliber. is there any other way for you to get me a tune without having to send it back. and yes the wideband read my fuel at about 14.1 to 14.4. ive been data logging while driving and the sct isnt showing and KR but its pulling the timing. no we didnt try another maf i was the only ls1 unless the lt1s are compadible.
03-04-2007, 02:00 PM
#5
email me the Dyno sheet with that airfuel log please. Ill figure out what is causing it. Could just be a vacuume leak also.
Is all the EGR stuff capped off or just unplugged.
What is KPA at idle? RPMS?
In the tunes i added 12% MORE fuel at wot, You shouldnt have needed that much but im always on the safe side for each set of mods. I would have to say if you ran it again with no maf it would be right on with the airfuel..
That is, Unless your o2 sensors arent getting hot enough and the engine is not going into closed loop to set up all the fueling, Then it would never try to fix itself.
As for the email tuning on that, im not sure if SCT is done with that part of thier software yet for GM, PM Slow on this forum and ask. His name is Ryan.
Is all the EGR stuff capped off or just unplugged.
What is KPA at idle? RPMS?
In the tunes i added 12% MORE fuel at wot, You shouldnt have needed that much but im always on the safe side for each set of mods. I would have to say if you ran it again with no maf it would be right on with the airfuel..
That is, Unless your o2 sensors arent getting hot enough and the engine is not going into closed loop to set up all the fueling, Then it would never try to fix itself.
As for the email tuning on that, im not sure if SCT is done with that part of thier software yet for GM, PM Slow on this forum and ask. His name is Ryan.
03-04-2007, 02:19 PM
#6
Looking at the dyno log, It looks like the maf is the cause. If it was descreened and wasnt put in the list of mods, then i didnt set up the maf table for that curve.
The fuel ratio is EXACTLY 1pt off with a complete flat line at 13.99 so the pcm is thinking that it is applying the 12.99 airfuel i asked for, but the maf is not accurate anymore so it is throwing it off by 1 pt exactly...
It is an easy fix, Just put in a good Maf with a screen in.
The fuel ratio is EXACTLY 1pt off with a complete flat line at 13.99 so the pcm is thinking that it is applying the 12.99 airfuel i asked for, but the maf is not accurate anymore so it is throwing it off by 1 pt exactly...
It is an easy fix, Just put in a good Maf with a screen in.
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04-06-2007, 01:48 AM
#8
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i have a stock screened maf, send me a pm or email at fil131@comcast.net if your interested, give me a price shipped and I'll see if we have a deal.