Stutter during acceleration

[PWinter]

Hey everyone, been watching the forum for a while but just registered hoping I might get some insight. I've had my ktuner for a little over 2 months and it has been awesome however almost over night my car started to stutter when under acceleration. And my knock control went from a pretty consistent .84 to now .97-1.03. all I have is the prl cobra street intake and was running the ktuner 19.5/23. I since have switched to a stock flash with the same issues. Any thoughts? Thanks

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[gtman]

First off, post a datalog (.kdlg in a zip file) with about 15-20 minutes of driving (after warmup) including a couple pulls if possible.

.84 is not a normal or expected knock control number and certainly anything above 1 is bad. What octane are you running?

 

[PWinter]

First off, post a datalog (.kdlg in a zip file) with about 15-20 minutes of driving (after warmup) including a couple pulls if possible.

.84 is not a normal or expected knock control number and certainly anything above 1 is bad. What octane are you running?

I only have 91 available to me unfortunately. I'll try to get a log after work

 

[zspeed]

@PWinter how’s your spark plugs?

 

[PWinter]

I haven't been able to check them yet this all started yesterday. I can pull them tomorrow morning. I'm also going to try and get a log this evening.

 

[gtman]

I only have 91 available to me unfortunately. I'll try to get a log after work

OK. On 91 with that tune you would expect to see something in the low to high .5 range. Bad batch of gas potentially? Were you hitting your boost targets? How many miles on your car?

 

[EP3R-T]

Sounds like bad gas or possibly an injector issue to me. What are your fuel trims looking like?

 

[PWinter]

29k miles I'm higher elevation so I've been hitting within 3psi of the targets. And stft and lyft have been around -3 to -6

 

[PWinter]

i home i did this right

 

[PWinter]

View on ktuner

 

[CivicSiAgain]

K.Con at 1.00 is very high....I’ll be curious to know what people say about the log.

 

[PWinter]

Me too. I reflashed back to stock and got fresh gas with the same issue so I'm not sure.

 

[gtman]

Ok, so here goes. First of all a bit of a comparison. I'm at about 670 feet above sea level. On 93 octane, I'm usually close to .49 and I'll sometime see it climb to maybe the low .6 range after some high rpm pulls. But, I have a non-Si...

Si's generally don't have the large spike in knock control after a high rpm pull. And yet, yours spiked quite a bit. You were at nearly .90 in cruise mode and jumped to 1.05 after the pulls. those numbers are very high. And I see you were hitting your boost targets but the targets were very low at full throttle... 10-12 psi.

But here's the thing. I'm not an expert on how much altitude plays a part of this. What's your elevation? You clearly are running rich. Also on the gas you used, did you refill at the same station or a different one?

You may want to ask KTuner to take a look at this log.

 

[PWinter]

Ok, so here goes. First of all a bit of a comparison. I'm at about 670 feet above sea level. On 93 octane, I'm usually close to .49 and I'll sometime see it climb to maybe the low .6 range after some high rpm pulls. But, I have a non-Si...

Si's generally don't have the large spike in knock control after a high rpm pull. And yet, yours spiked quite a bit. You were at nearly .90 in cruise mode and jump to 1.05 after the pulls. those numbers are very high. And I see you were hitting your boost targets but the targets were very low at full throttle... 10-12 psi.

But here's the thing. I'm not an expert on how much altitude plays a part of this. What's your elevation? You clearly are running rich. Also on the gas you used, did you refill at the same station or a different one?

You may want to ask KTuner to take a look at this log.

I'm about 6k feet, yes I got gas from a different station. The gas I was using when this first started was what I had been using for several days prior with no issues. @KTuner any input on what to check or possible causes?

 

[KTuner]

It sounds like it's not tune related. That would make it mechanical.

For a look at the maximum achieved relative pressure take your maximum boost (@gtman mentioned 10-12PSI) and add the absolute value of the TC Pressure PSI reading when you're at idle or not on the throttle. If TC Pressure reads -10PSI it's 10. 12+10 is 22 etc.

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