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Sputtering at beginning of WOT

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convertix

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I wanted to follow up with the fix to this issue. In short, the plugs weren't gapped properly causing spark plug blowout under high boost. The plugs needed to be .030 and they were about .045. Way too much gap for a boosted car. Sometimes I would get lucky and a good pull might sneak in there from time to time which was making it harder to diagnose the problem.
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hossman

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I’m having similar issues and changing out the plugs tomorrow. I hope it fixes it for me too. I suspect there is a plug or plugs not gapped properly.
 

hossman

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Plugs didn’t fix the hesitation issue and it’s getting frustrating. I was able to get a log where it hesitated twice so hopefully the tuner can see something.
 
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convertix

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Plugs didn’t fix the hesitation issue and it’s getting frustrating. I was able to get a log where it hesitated twice so hopefully the tuner can see something.
I can certainly understand your frustration. I now have an issue with positive knock appearing in 3rd gear only and it doesnt happen all the time. It's probably a loose exhaust bolt or O2 sensors going out.

What kind of specs do you have and I'll try to help? Are you on E85, etc?
 

hossman

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17 Mustang GT
- 6spd Manual
- Roush 2300 TVS
- 79mm Pulley
- FIC1000 Injectors
- VMP Twin 67 Throttle Body
- Pmas 120 Intake
- 170 Degree Reische Thermostat
- VMP Triple Pass Heat Exchanger
- Fuel Pump Booster
- NGK 6510 Plugs
- VMP Tune For 93 & 100 Octane

I notice the hesitation most in 3rd or 4th gear around 2500-3500 rpm if I’m just leisurely going along and go WOT it will pull normal briefly then get a hesitation and pull normal, but sometimes it will hesitate a 2nd time in the same pull. You can really notice the hesitation. I made sure I shut traction control completely off to rule out the Ford nannies. Heck it’s even done this in 5th gear a few times.
 
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convertix

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17 Mustang GT
- 6spd Manual
- Roush 2300 TVS
- 79mm Pulley
- FIC1000 Injectors
- VMP Twin 67 Throttle Body
- Pmas 120 Intake
- 170 Degree Reische Thermostat
- VMP Triple Pass Heat Exchanger
- NGK 6510 Plugs
- VMP Tune For 93 & 100 Octane

I notice the hesitation most in 3rd or 4th gear around 2500-3500 rpm if I’m just leisurely going along and go WOT it will pull normal briefly then get a hesitation and pull normal, but sometimes it will hesitate a 2nd time in the same pull. You can really notice the hesitation. I made sure I shut traction control completely off to rule out the Ford nannies. Heck it’s even done this in 5th gear a few times.
Are you able to look at the datalogs in LiveLink? Check the fuel trims if they are less than .97 during WOT or greater than 1.05.
 

hossman

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No I’m not able to look at the logs.
 

hossman

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My tuner got back to me with a tune revision saying the Tip In Torque Control was way off so he shut it off with some other minor tweaks so I will see how it goes once the rain stops.
 

hossman

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My tuner sent me a revision today turning off tip in torque control and making a few small adjustments. Let’s hope that was the culprit.
 

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hossman

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It was raining all day so I didn’t get to go any pulls
 

hossman

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Still a bit damp but I took it out for a short spin and seems like the tune revision fixed the issue. I’ll get some good pulls the next few days and see for sure.
 
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convertix

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Still a bit damp but I took it out for a short spin and seems like the tune revision fixed the issue. I’ll get some good pulls the next few days and see for sure.
Awesome, hope that works out for you. These cars are beyond sensitive. Tune has to be perfect.
 

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Looking st the log, actual WOT is in the low 90s throughout. Still rich imho. It takes a long time for the tuner to get back. Sometimes can take 1.5 weeks! One thing is for sure is the car is running better than yesterday, but still not good enough. The only thing I changed was readjust the baseline on the regulator. Appreciate your help.
I would change tuners Lund would get back to me on average in less than 2 hours during work hours... and got my car dialed in.., in just 3 tunes over 3 days... and I could also now pass emissions in NYS running LT headers. I used two different tuners before Lund and spent countless hours data logging, researching, testing, changing out parts, drive cycles etc... Lund were great to work with. They also give you a conservative tune that is safe... I would rather have a few less hp and a safe tune on a street car... the issue is these remote tuners quickly lose interests if they/you run into trouble... if everything is mechanically correct on the car their canned tunes can be dialed in quickly... if you have any mechanical issues sometimes they can give you good advice and sometimes they can’t...
 

hossman

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Ran both the revised 93 & 100 octane tune and the car is running flawlessly. I’m thankful the tune revision did the trick!
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