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Discussion Starter · #61 ·
I think this is one of those things you just have to be methodical with resolving. So, things like the tune need to be eliminated. I've seen people chase issues like yours a long way. Hopefully, you'll find the cause soon.
Alright, as far as the misfire for now(not throwing any DTCs) I’m relatively okay to continue driving/racing?
 

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Methodical is definitely the correct approach to pursue by only changing one thing at a time to see if it makes a difference and corrects the problem. Changing more than one thing at a time will make it impossible to actually determine what the root cause is of the problem.

Just as a test try unplugging your IAT connector at the airbox to see if the PCM sets a DTC for it so you know the computer is responding correctly by starting the car and letting it run for a few minutes until the CEL comes on.. If it does not set the DTC for an IAT then you may have a PCM issue, but if it does set a DTC then yuu know it is operating properly.

BD
 

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Discussion Starter · #63 ·
Methodical is definitely the correct approach to pursue by only changing one thing at a time to see if it makes a difference and corrects the problem. Changing more than one thing at a time will make it impossible to actually determine what the root cause is of the problem.

Just as a test try unplugging your IAT connector at the airbox to see if the PCM sets a DTC for it so you know the computer is responding correctly by starting the car and letting it run for a few minutes until the CEL comes on.. If it does not set the DTC for an IAT then you may have a PCM issue, but if it does set a DTC then yuu know it is operating properly.

BD
Okay, so correct me if I’m wrong
1st: Disconnect IAT and check for DTC
2nd: Switch to stock tune and check for misfire
3rd: Replace spark plugs and check for misfire
4th: Replace Coil Packs and check for misfire

I would also like to note when I removed the coil on cylinder 1 I did notice a bit of white dust/powder/corrosion on the boot.
 

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That would be my approach after I was 100% sure there is no issues from the IC install.

The white dust/powder on #1 boot could be indication of oxidation from moisture getting past the top of coil pack seal to valve cover which could lead to misfires.

BD
 

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Discussion Starter · #65 ·
That would be my approach after I was 100% sure there is no issues from the IC install.

The white dust/powder on #1 boot could be indication of oxidation from moisture getting past the top of coil pack seal to valve cover which could lead to misfires.

BD
I disconnected IAT and it did show a DTC! So next I placed new plugs gapped to .028 and immediately noticed the car ran smoother. So I went for a drive, misfire count went to 4 then until I got on the highway and WOT which it shot up to 55 with -3 ign correction so I pulled over, reset the ECU learning and then did a few WOT runs with the misfire count only going up to 6 which is normal to me. What wasn't normal was the constant negative ignition correction on all cylinders between -1 and -4. So I flashed cobb stage 1 instead of stage 2 and have since noticed zero ign correction and a max misfire count of 6. I will also attached a datalog of a pull I did on Stage 1 with my new spark plugs after the ECU reset.

Here are a few different ways to access the datalog in case anyone doesn't use google or such.

Google DATALOG
Dropbox DATALOG
Filebin DATALOG
Icloud DATALOG
 

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Discussion Starter · #66 ·
That would be my approach after I was 100% sure there is no issues from the IC install.

The white dust/powder on #1 boot could be indication of oxidation from moisture getting past the top of coil pack seal to valve cover which could lead to misfires.

BD
The boots don’t look too awful and I didn’t end up cleaning them as I was going to save that as a later step due to the step by step approach I was taking.

Automotive tire Motor vehicle Automotive lighting Bumper Automotive design
 

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All the coil boots look the same, so I don't think it's a moisture issue. I believe it's just the interaction between the rubber and the aluminum of the head from heat cycles causing some migration of aluminum oxide dust to accumulate on the ends of the boots.

Nor sure what the actual difference between stage 1 and 2 is on the cobb tuner but it seems that stage 2 is not happy in your car.

BD
 

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Discussion Starter · #68 ·
All the coil boots look the same, so I don't think it's a moisture issue. I believe it's just the interaction between the rubber and the aluminum of the head from heat cycles causing some migration of aluminum oxide dust to accumulate on the ends of the boots.

Nor sure what the actual difference between stage 1 and 2 is on the cobb tuner but it seems that stage 2 is not happy in your car.

BD
Yeah seems so, how about the data log? Anything look wrong? Thank you for all your help as well!!
 

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Other than the negative IGN corrections it all looks pretty good. Not sure on why so much negative corrections other than possible poor quality tank of fuel. Did you just get fuel before this issue started and it was just a coincidence that you installed the IC after filling up.

Do you use top tier fuels or just 93 fuel from cheapest places. One tip is never get fuel from a station if you see the tanker dumping fuel into the stations tanks. It stirs up all the dirt/crud from the bottom of the big tanks which takes 24 hours to settle back to the bottom of the tank.

BD.
 

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Discussion Starter · #70 ·
Other than the negative IGN corrections it all looks pretty good. Not sure on why so much negative corrections other than possible poor quality tank of fuel. Did you just get fuel before this issue started and it was just a coincidence that you installed the IC after filling up.

Do you use top tier fuels or just 93 fuel from cheapest places. One tip is never get fuel from a station if you see the tanker dumping fuel into the stations tanks. It stirs up all the dirt/crud from the bottom of the big tanks which takes 24 hours to settle back to the bottom of the tank.

BD.
I use the best gas I can find, I believe this tank is from shell and of course 93! However I have noticed that this specific QuickTrip gas station reacts extremely well with my tune and is usually a few cents cheaper than shell. In fact this station reacts better than any other gas I’ve ever had in the vehicle, I think I’ll fill up with that and go from there. Are there any other factors that could cause negative ignition correction? Also thanks for the tip! Never thought about that but makes perfect sense. Also I’ve filled up multiple times since the intercooler install…I tend to drive allot.
 

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Quicktrip is a top tier station so if your car likes it then keep using it, feed her what she likes best.


I did notice that when it was in negative corrections the AFR was a bit rich so it may have been just the PCM doing its job of managing timing based on fueling and air flow/temps.

I would just keep an eye on the misfire and corrections to see if over time the adaptive learning of the PCM strategy will sort things out on its own.

BD
 

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Discussion Starter · #72 ·
Quicktrip is a top tier station so if your car likes it then keep using it, feed her what she likes best.


I did notice that when it was in negative corrections the AFR was a bit rich so it may have been just the PCM doing its job of managing timing based on fueling and air flow/temps.

I would just keep an eye on the misfire and corrections to see if over time the adaptive learning of the PCM strategy will sort things out on its own.

BD
Alrighty, Thank you again for all your help!! I’ll give you an update in about a day or two on how she’s running.
 

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I’m having a misfire issue after installing cvfab race intercooler. I was on stage 1 Cobb tune before the intercooler and at max had a misfire count of 3 on cold start occasionally and never any negative ignition correction. Immediately after the install I started it up and misfire count went high as well as negative correction so I reset the ecu thinking it needed to relearn or such. Which of course after it ran quite a bit better but now I get misfire count up to about 50 to a 100 depending on how many pulls I do. This is within a 30 min drive. However I rarely see negative ignition correction and when I do it’s max -2. I would also note that I never feel or notice the misfires either. I will post a data-log of a run after work.
Check your spark plugs. Make sure you have the right gap. Also, try one step colder plugs like the NGK most of us use.
If you are running a stage 1 93 octane map, use the stage 1 91 octane map with only 93 octane in the tank. It may be possible that the local stations have poor gas. I would suggest having the gauge: Knock Octane Modifier on your accessport so you can easy if it is bad fuel. Most of us have gone through the same issues, so we all help each other diagnosing the source of issues.
 

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Been creeping here just to learn. But an FYI all the QT's in central Texas have removed their Top Tier stickers.
The last time I got a bad tank of gas was at a QT station...
 
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