Warm start issue
Thread Starter
Instructor
Joined: Jan 2006
Posts: 114
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From: Sachse Texas
Warm start issue
I have an 04 C5 with dte 3.73's, lg long tubes, borla stingers, halltech, G5X3 and thermostat. Car has 2k miles on it and is a daily driver.
These were all installed by a very reputable tuner.
I have noticed that my car is hard to start on a warm start but has no problems at all starting from cold. I noticed this after the cam install about a month ago. I have been back to the tuner a couple of times to no avail. The tuner added more air which makes the car immediately rev to about 3k rpm for a couple of seconds when started so now it doesn't die on warm start. I am not comfortable with this fix and the tuner says the computer will learn some and it should get better.
Anyone else experience this issue.
These were all installed by a very reputable tuner.
I have noticed that my car is hard to start on a warm start but has no problems at all starting from cold. I noticed this after the cam install about a month ago. I have been back to the tuner a couple of times to no avail. The tuner added more air which makes the car immediately rev to about 3k rpm for a couple of seconds when started so now it doesn't die on warm start. I am not comfortable with this fix and the tuner says the computer will learn some and it should get better.
Anyone else experience this issue.
Pro
Joined: Sep 2005
Posts: 538
Likes: 9
From: Geneva, IL Bring back the Chief!
St. Jude Donor '06-'07-'08-'09-'10,'13-'14,'19-'20-'21-'22
How about that? I just got thru this problem. Look at my sig and you might see a parallel.
I just did the H/C mod with AFR205 and g5x3.
I had two things off which, when corrected, took care of the problem.
1. My LTFT's were quite a ways off. So I had to retune my VE table, particularly in the low rpm ranges.
2. ThenI found that my MAF table was off by about 15%. So I adjusted that too.
Now I've done several other things, but I think it was the MAF recalibration that solved this issue.
Good luck.
Dick
I just did the H/C mod with AFR205 and g5x3.
I had two things off which, when corrected, took care of the problem.
1. My LTFT's were quite a ways off. So I had to retune my VE table, particularly in the low rpm ranges.
2. ThenI found that my MAF table was off by about 15%. So I adjusted that too.
Now I've done several other things, but I think it was the MAF recalibration that solved this issue.
Good luck.
Dick
Instructor
Joined: Dec 2006
Posts: 226
Likes: 0
From: Newburgh NY
One thing to consider is that when the car starts, whether cold or warm, is that for at least a few seconds it is in Open Loop until the O2 sensors catch up and it goes from Open to Closed loop. During this open loop operation Air/Fuel is derived from the Fuel/Open Loop/Eq ratio table (simple divisor from Stoich A/F ie: 14.7/1.139 = startup A/F ratio of 12.9).
Depending on the cam, initial timing (you may want ot back this off slightly in the process also just for startup), MAF settings etc., both the startup Air/Fuel ration as well as the RAF (Running Air Flow which is based on Engine Coolant Tempt) are going to help in the startup and initial idle. Assuming there are no vacuum leaks or other mechanical issues, this is where I'd start looking. I'd hook a scanner up to it and log for Adaptive IDLE (STIT's), Open/Closed Loop, engine temp, etc.
Again, this is only a starting point and there may be other things going on here. But I've run into this situation a number of times. Just a suggestion and somethign to consider.
Depending on the cam, initial timing (you may want ot back this off slightly in the process also just for startup), MAF settings etc., both the startup Air/Fuel ration as well as the RAF (Running Air Flow which is based on Engine Coolant Tempt) are going to help in the startup and initial idle. Assuming there are no vacuum leaks or other mechanical issues, this is where I'd start looking. I'd hook a scanner up to it and log for Adaptive IDLE (STIT's), Open/Closed Loop, engine temp, etc.
Again, this is only a starting point and there may be other things going on here. But I've run into this situation a number of times. Just a suggestion and somethign to consider.
Team Owner
Joined: May 2004
Posts: 26,345
Likes: 231
From: SoCal
I had the same problem. Cold starts good. Warm starts (some times) would die. Tuner had to work on it ....... but finally got it fixed. 
BTW: no problem with warm starts on new engine.....so you can always fix it that way
DH
BTW: no problem with warm starts on new engine.....so you can always fix it that way
DH
