$50 Amazon gift card to the first person that figures this "misfire" issue out

Tomlouns

Well-Known Member
Joined
Sep 16, 2017
Messages
156
Reaction score
32
Location
NY
Vehicle(s)
2015 Mustang GT Convertible
I NEED HELP - there is no CEL... I am not sure what to do next... Please let me know your thoughts.

This issue started / I first noticed it after WOT second gear pull to about 7400 RPM... I have not gone WOT with the car in about 3 weeks... The last time I did was for testing with PBD... about three weeks ago.

The car idles fine but if you put your foot on the gas in gear... it has a misfire then after a 1 second will kick in hard and then run fine... If I role into the gas "very" slow... just barley toughing the peddle it will not have the hesitation and a knock and then I can accelerate normally... I have attached 3 logs for review... It always had long hot starts... now the hot starts are 2x as long and sometimes it even "times out" and I have to press the start button again, it then will start the second time... Cold starts are about the same as they were before, maybe a little longer...

You can see the car now runs lean on idle... it didn't before. Why would this change?

Thoughts I have:
1. Mass air flow sensor?( I have cleaned it... but don't know how to test this)
2. Bad gas? I ran it down to 1/2 a tank and filled it up with Mobile 93 this made it run better but I am still having the issue listed above... I am now down to 3/4 tank and will top it off again today...
3. Spark plugs.. nope... but I put new ones in just in case... I have attached a pic. of the old ones they were all the same
4. Bad Coil? don't know how to test this -
5. Bad knock sensor? I don't know how to test this...
6. Bad fuel pump? It is new an the fuel pump and voltage booster. and if I am reading the fuel trims right... they look like they are in the normal range.
7. A issue with the tune? I am checking with PBD...

Setup:
2015 Mustang GT 32,000 miles and only about 800 with the whipple on it...
whipple stage 2 gen 3
132mm TB
Whipple intake
DW 95LB injectors
DW 400LPH fuel pump with a voltage booster
long tube headers with green flow cats
NGK 6510 LTR7IX-11 gap .028"
Magnaflow 3 in cat back
Auto trans
Oil pump gears
spark plug 1.jpg





Advertisement

 

Attachments

Last edited:
OP

Tomlouns

Well-Known Member
Joined
Sep 16, 2017
Messages
156
Reaction score
32
Location
NY
Vehicle(s)
2015 Mustang GT Convertible
  • Thread starter
  • Thread Starter
  • #2
Oh... one other thing... maybe the TB isn't working right... but I don't know how to test that either or read the logs and tell...
 

Stang 19

Well-Known Member
Joined
Sep 5, 2018
Messages
575
Reaction score
157
Location
Ca
First Name
Mike
Vehicle(s)
2020 GT500 Ford Performance Blue
I NEED HELP - there is no CEL... I am not sure what to do next... Please let me know your thoughts.

This issue started / I first noticed it after WOT second gear pull to about 7400 RPM... I have not gone WOT with the car in about 3 weeks... The last time I did was for testing with PBD... about three weeks ago.

The car idles fine but if you put your foot on the gas in gear... it has a misfire then after a 1 second will kick in hard and then run fine... If I role into the gas "very" slow... just barley toughing the peddle it will not have the hesitation and a knock and then I can accelerate normally... I have attached 3 logs for review... It always had long hot starts... now the hot starts are 2x as long and sometimes it even "times out" and I have to press the start button again, it then will start the second time... Cold starts are about the same as they were before, maybe a little longer...

You can see the car now runs lean on idle... it didn't before. Why would this change?

Thoughts I have:
1. Mass air flow sensor?( I have cleaned it... but don't know how to test this)
2. Bad gas? I ran it down to 1/2 a tank and filled it up with Mobile 93 this made it run better but I am still having the issue listed above... I am now down to 3/4 tank and will top it off again today...
3. Spark plugs.. nope... but I put new ones in just in case... I have attached a pic. of the old ones they were all the same
4. Bad Coil? don't know how to test this -
5. Bad knock sensor? I don't know how to test this...
6. Bad fuel pump? It is new an the fuel pump and voltage booster. and if I am reading the fuel trims right... they look like they are in the normal range.

Setup:
2015 Mustang GT 32,000 miles and only about 800 with the whipple on it...
whipple stage 2 gen 3
132mm TB
Whipple intake
DW 95LB injectors
DW 400LPH fuel pump with a voltage booster
long tube headers with green flow cats
NGK 6510 LTR7IX-11 gap .028"
Magnaflow 3 in cat back
Auto trans
Oil pump gears
spark plug 1.jpg
Oh... one other thing... maybe the TB isn't working right... but I don't know how to test that either or read the logs and tell...
1. did you try disconnecting the battery for a few minutes? Then start her up and see if working now?
2. Call Whipple ...chances are they ha e seen this before.
 

Nagare

Well-Known Member
Joined
Feb 1, 2017
Messages
3,836
Reaction score
2,019
Location
Ft Lauderdale
Vehicle(s)
2017 Lightning Blue V6
Vehicle Showcase
1
I can't check the logs right now, but have you checked the clearance on your headers? Any sign of your exhaust hitting the trans mount at all? Any signs of your exhaust hitting the chassis anywhere? How's clearance above the engine if you have a strut tower brace?

Just naming a few issues I have seen, everything but the first happened to me on my V6 and were causing high knock readings. Wasn't a noticeable cut in power, but with the Whipple I can see it being exaggerated (misfire though I would say is more likely fuel or tune related). If you run an octane booster, how do things work out? If it is still similar, I'd say false knock and maybe they can tone down the sensitivity of the knock sensors.

From the first spreadsheet (looking in Excel only at knock and RPMs), all of your positive knock comes in below 2500rpms. Makes me thing when you go WOT something is hitting somewhere.

edit » how long have the green cats been on? Can you test without them? Decent chance you've burned those out too, non-OEM cats seem to only cause issues from what I've seen. Do you have the O2 sensors plugged into the proper banks (ie right sensor on right bank)? Have you tried putting a spacer on the O2 sensors? Should be throwing a code if it really is an issue, but who knows.
 
OP

Tomlouns

Well-Known Member
Joined
Sep 16, 2017
Messages
156
Reaction score
32
Location
NY
Vehicle(s)
2015 Mustang GT Convertible
  • Thread starter
  • Thread Starter
  • #5
I can't check the logs right now, but have you checked the clearance on your headers? Any sign of your exhaust hitting the trans mount at all? Any signs of your exhaust hitting the chassis anywhere? How's clearance above the engine if you have a strut tower brace?

Just naming a few issues I have seen, everything but the first happened to me on my V6 and were causing high knock readings. Wasn't a noticeable cut in power, but with the Whipple I can see it being exaggerated (misfire though I would say is more likely fuel or tune related). If you run an octane booster, how do things work out? If it is still similar, I'd say false knock and maybe they can tone down the sensitivity of the knock sensors.

From the first spreadsheet (looking in Excel only at knock and RPMs), all of your positive knock comes in below 2500rpms. Makes me thing when you go WOT something is hitting somewhere.

edit » how long have the green cats been on? Can you test without them? Decent chance you've burned those out too, non-OEM cats seem to only cause issues from what I've seen. Do you have the O2 sensors plugged into the proper banks (ie right sensor on right bank)? Have you tried putting a spacer on the O2 sensors? Should be throwing a code if it really is an issue, but who knows.
1. I didn't see or hear any leaks on the cooks LT
2. Car seems to run well once you get past first touching the gas... so once I am into WOT I am not feeling or hearing any issues.
3. I have had this whole setup on for less than 800 miles... including the green flow cats
4. yes, the O2 sensors are plugged in correctly, this issue just started... and there codes....
5. I will add some octane booster today... but I an not hearing any knock other than when I first press the gas... and if I very slowly press the gas I can avoid the hesitation and knock ..
 

Nagare

Well-Known Member
Joined
Feb 1, 2017
Messages
3,836
Reaction score
2,019
Location
Ft Lauderdale
Vehicle(s)
2017 Lightning Blue V6
Vehicle Showcase
1
1. I didn't see or hear any leaks on the cooks LT
2. Car seems to run well once you get past first touching the gas... so once I am into WOT I am not feeling or hearing any issues.
3. I have had this whole setup on for less than 800 miles... including the green flow cats
4. yes, the O2 sensors are plugged in correctly, this issue just started... and there codes....
5. I will add some octane booster today... but I an not hearing any knock other than when I first press the gas... and if I very slowly press the gas I can avoid the hesitation and knock ..
1) Not leaks, just wear/hit marks on them or chassis pieces nearby to them
3) if you can test without the cats, could be worth a shot but they definitely shouldn't be burned out that soon
4) P0420 and P0430 or more beyond that? If it's those, the defouler/spacer would get rid of them. Those cause CELs though.

Only other idea I could mention is maybe your battery is on its way out? I know something like that happened to @ahl395 but I think that was also tied to his meth kit.
 
OP

Tomlouns

Well-Known Member
Joined
Sep 16, 2017
Messages
156
Reaction score
32
Location
NY
Vehicle(s)
2015 Mustang GT Convertible
  • Thread starter
  • Thread Starter
  • #7
1. did you try disconnecting the battery for a few minutes? Then start her up and see if working now?
2. Call Whipple ...chances are they ha e seen this before.
yes, I did tried this after I cleaned the air flow sensor...
 
OP

Tomlouns

Well-Known Member
Joined
Sep 16, 2017
Messages
156
Reaction score
32
Location
NY
Vehicle(s)
2015 Mustang GT Convertible
  • Thread starter
  • Thread Starter
  • #8
1) Not leaks, just wear/hit marks on them or chassis pieces nearby to them
3) if you can test without the cats, could be worth a shot but they definitely shouldn't be burned out that soon
4) P0420 and P0430 or more beyond that? If it's those, the defouler/spacer would get rid of them. Those cause CELs though.

Only other idea I could mention is maybe your battery is on its way out? I know something like that happened to @ahl395 but I think that was also tied to his meth kit.
1. I will take a second look... but didn't notice anything
2. New battery 800 miles ago...
3. no codes are coming up...
 

helloWorld

Active Member
Joined
Oct 20, 2018
Messages
36
Reaction score
18
Location
Lincoln, NE
Vehicle(s)
2004 Nissan Maxima SE
All I can tell you is my previous experience and my own logic that led to a successful diagnosing of a misfire on my NA 2013 Mustang GT that I used to have.

Let's not get complex here, the explosion in one cylinder needs three things: air, fuel, and spark. If any of those three are missing, then you will have a misfire.

Air going in is probably never going to be an issue, which leaves fuel and spark. For me, I was having a misfire in cylinder number three. So, I decided to start with spark troubleshooting.

I swapped the spark plug from cylinder eight into cylinder three, thus placing the "suspect" spark plug into cylinder eight. I cleared the code and drove the car around for awhile. I was still having a misfire in cylinder three, which meant that the spark plug was not the problem. I did the same thing with the coil, but this time swapping the coils between cylinder 6 and cylinder 3. Cleared the code, drove around, still had a misfire in cylinder 3. To me, that cleared air and spark being suspect, because the only other thing I could possibly troubleshoot was the actual wiring harness that fed the coils and I didn't have a spare laying around to swap out. You could get more complex and say that maybe there was a blockage in the intake manifold in the runner that fed air into cylinder 3, but let's be honest, how often does that happen?

Moving onto fuel, the easiest and only thing I could really troubleshoot with was swapping around injectors. I swapped the injector from cylinder 3 out with the injector from cylinder 5, cleared the code and drove around. Guess what, the misfire moved from cylinder 3 to cylinder 5. Turned out, I had a bad fuel injector.

Yes, I agree that your issue could be more complex than just the simple air, fuel and spark. You could have an issue with your engine internals. You could have an issue with the ECU. There could be an issue in one of the harnesses. However, I would suggest troubleshooting the easy things before pulling your hair out dwelling on the more complex potentials.
 
OP

Tomlouns

Well-Known Member
Joined
Sep 16, 2017
Messages
156
Reaction score
32
Location
NY
Vehicle(s)
2015 Mustang GT Convertible
  • Thread starter
  • Thread Starter
  • #10
All I can tell you is my previous experience and my own logic that led to a successful diagnosing of a misfire on my NA 2013 Mustang GT that I used to have.

Let's not get complex here, the explosion in one cylinder needs three things: air, fuel, and spark. If any of those three are missing, then you will have a misfire.

Air going in is probably never going to be an issue, which leaves fuel and spark. For me, I was having a misfire in cylinder number three. So, I decided to start with spark troubleshooting.

I swapped the spark plug from cylinder eight into cylinder three, thus placing the "suspect" spark plug into cylinder eight. I cleared the code and drove the car around for awhile. I was still having a misfire in cylinder three, which meant that the spark plug was not the problem. I did the same thing with the coil, but this time swapping the coils between cylinder 6 and cylinder 3. Cleared the code, drove around, still had a misfire in cylinder 3. To me, that cleared air and spark being suspect, because the only other thing I could possibly troubleshoot was the actual wiring harness that fed the coils and I didn't have a spare laying around to swap out. You could get more complex and say that maybe there was a blockage in the intake manifold in the runner that fed air into cylinder 3, but let's be honest, how often does that happen?

Moving onto fuel, the easiest and only thing I could really troubleshoot with was swapping around injectors. I swapped the injector from cylinder 3 out with the injector from cylinder 5, cleared the code and drove around. Guess what, the misfire moved from cylinder 3 to cylinder 5. Turned out, I had a bad fuel injector.

Yes, I agree that your issue could be more complex than just the simple air, fuel and spark. You could have an issue with your engine internals. You could have an issue with the ECU. There could be an issue in one of the harnesses. However, I would suggest troubleshooting the easy things before pulling your hair out dwelling on the more complex potentials.
I like your workflow, the issue is the plugs all looked fine... and I am not getting any codes... so I have no idea what cylinder might be causing a issue.
 

jlstro3

Well-Known Member
Joined
Apr 1, 2016
Messages
130
Reaction score
31
Location
Muscatine, Iowa
First Name
Josh
Vehicle(s)
2016 Mustang GT
Last year i noticed my STFT's were creeping up too high under boost, so i threw in a DW400 pump. When doing logging if i would stab the gas at say, 2700 to try and get a full 3rd gear log it would misfire and then run lean. However if i moved the rpm's up to 3000-3300 to start my pull, it did not happen. It also did not happen when launching in first gear. Switched tuners this season, and first log did the same thing. Tuner suggested a plug swap and re-gap so we're going to start there. Hope to log wednesday after it gets out of the shop (other mods going in too). It's really hard to tell what started it all as last year was a big upgrade year, 6r80 swap, so i was fighting issues w/ that too but in my mind it sure felt like it was after the DW400 upgrade. I'll check back in this thread after i do a couple logs.
 
OP

Tomlouns

Well-Known Member
Joined
Sep 16, 2017
Messages
156
Reaction score
32
Location
NY
Vehicle(s)
2015 Mustang GT Convertible
  • Thread starter
  • Thread Starter
  • #12
My installer wanted me to use the DW400 pump... I really don't think Mustangs like them... but it was not causing this issue for the first 800 miles... unless it failing now...
Please keep me posted on how you progress...
Last year i noticed my STFT's were creeping up too high under boost, so i threw in a DW400 pump. When doing logging if i would stab the gas at say, 2700 to try and get a full 3rd gear log it would misfire and then run lean. However if i moved the rpm's up to 3000-3300 to start my pull, it did not happen. It also did not happen when launching in first gear. Switched tuners this season, and first log did the same thing. Tuner suggested a plug swap and re-gap so we're going to start there. Hope to log wednesday after it gets out of the shop (other mods going in too). It's really hard to tell what started it all as last year was a big upgrade year, 6r80 swap, so i was fighting issues w/ that too but in my mind it sure felt like it was after the DW400 upgrade. I'll check back in this thread after i do a couple logs.
 

Jay-rod427

Well-Known Member
Joined
Jun 8, 2016
Messages
2,423
Reaction score
985
Location
Kansas
Vehicle(s)
2016 GT C/S
Whipple bypass valve. Doesn't close quickly creating the hesitation. Make sure all the vaccum lines are tight and good connections. Also vacuum leak is why lean idle. Have a shop smoke test the intake/vacuum system. But extra scrutiny around the blower bypass valve vacuum reference.

Have you sent the logs to PBD? They should be able to tell if there's a vacuum leak, or advise otherwise.
 

ahl395

Well-Known Member
Joined
Dec 30, 2015
Messages
2,814
Reaction score
1,189
Location
NJ
First Name
Allan
Vehicle(s)
2017 Mustang GT, 2006 Infiniti G35X
You said you have a misfire... but your not getting any codes? If you are not getting codes or a flashing CEL then what you are feeling is not a misfire...

Get what your feeling on a log and send to your tuner,


1) Not leaks, just wear/hit marks on them or chassis pieces nearby to them
3) if you can test without the cats, could be worth a shot but they definitely shouldn't be burned out that soon
4) P0420 and P0430 or more beyond that? If it's those, the defouler/spacer would get rid of them. Those cause CELs though.

Only other idea I could mention is maybe your battery is on its way out? I know something like that happened to @ahl395 but I think that was also tied to his meth kit.
Yep that was my meth kit
 
OP

Tomlouns

Well-Known Member
Joined
Sep 16, 2017
Messages
156
Reaction score
32
Location
NY
Vehicle(s)
2015 Mustang GT Convertible
  • Thread starter
  • Thread Starter
  • #15
Whipple bypass valve. Doesn't close quickly creating the hesitation. Make sure all the vaccum lines are tight and good connections. Also vacuum leak is why lean idle. Have a shop smoke test the intake/vacuum system. But extra scrutiny around the blower bypass valve vacuum reference.

Have you sent the logs to PBD? They should be able to tell if there's a vacuum leak, or advise otherwise.
Yes, I have sent them over... he is trying to figure it out... FYI I did a smoke test after the install and it passed. I have double check the lines everything looks like it should...
 
Last edited:

Advertisement





 
5 SPURS - 1


Advertisement
Top