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Discussion Starter · #1 · (Edited)
I have an 02 GT which is experiencing sputtering during acceleration. It's worth noting that I recently installed a ProCharger and had the car tuned by a well-respected professional. All of the aforementioned problems began after installing the ProCharger. I am certain that the tuner is not to blame. In short, the car falls on it's face if you don't feather the gas carefully. When cold, the car often stalls, unless you, again, feather the gas pedal.

Here's what I know: The person who tuned the car told me that material from the catalytic converters was found behind my car after the dyno work. He told me to drop the H-Pipe and inspect the cat's. Inside, I discovered that the passenger-side converter was completely empty, and the driver-side cat had a large chunk of material lodged sideways. After removing the material, I ran a plumbing fish back thru the mufflers and tailpipes. To the extent I could tell if there were any obstructions, all I can tell is that the fish went thru to the tailpipe. So, I put it all back together, and still no change. While running the plumbing fish into the tailpipes, I noticed a significant carbon build up on only the driver-side exhaust tip.

Since then, I've replace both upstream and downstream O2 sensors. I've replaced the NGK 3951 TR55 V-Power spark plugs with colder version NGK 4177 TR6 V-Power. As I'm writing this, I am thinking about the NGK heat-range numbering scheme, and I think I only went .5 colder (55 vs. 6). In case you're not aware, heat range for NGK plugs is reverse (i.e. "5" is hotter than "6"). Regardless, It's worth noting that the plugs I removed showed no sign of fouling; rather, they were a lovely/healthy tan color. Replacing the spark plugs had no effect on the sputtering issue. Not sure if it's valuable, but according to the markings on the coil packs, they appear to be OEM Ford. I probably should have replaced them with aftermarket coils. My tuner instructed me to: 1.) Install an Innovative Wideband AFR gauge, and 2.) Perform a pressure check on the ProCharger system to see if there are any obvious leaks. If this produces anything valuable, I'll report back.

FYI... NGK Heat Range Reference: https://www.ngk.com/how-do-i-find-a-colder-or-hotter-plug-3

Any assistance would be appreciated. Thank you in advance.
 

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Have you checked for stored codes in the ECM?

I wouldn’t trust your exhaust system at all. Material can continue to dislodge and restrict the flow, regardless of snaking it out. I’d drop the cats and run straight pipes for testing. Eliminate the exhaust from the equation temporarily. I suspect you have more debris.

I don’t recommend aftermarket coils, they’re not really improvement over stock. Aftermarket coils are generally of lesser quality than OEM and have a poor reputation AFAIK.

Don’t just throw parts at the problem. Diagnose and repair. Maybe our Tech-Expert can give you some sound advice.
 

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Discussion Starter · #3 ·
Welcome and thank you for joining MustangEvolution!
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Have you checked for stored codes in the ECM?

I wouldn’t trust your exhaust system at all. Material can continue to dislodge and restrict the flow, regardless of snaking it out. I’d drop the cats and run straight pipes for testing. Eliminate the exhaust from the equation temporarily. I suspect you have more debris.

I don’t recommend aftermarket coils, they’re not really improvement over stock. Aftermarket coils are generally of lesser quality than OEM and have a poor reputation AFAIK.

Don’t just throw parts at the problem. Diagnose and repair. Maybe our Tech-Expert can give you some sound advice.
Thanks for the response and advice. I am certain that the H-Pipe and cats are free of obstruction. However, I agree with you that there's still high potential and probability for some cat material lodged in the mufflers. I also agree that throwing parts at the problem is no solution either.

Over the weekend, I consulted with some of my local SME's who weren't awfully helpful. One suggested performing a forced induction pressure-test. Meaning, force 5-6 psi into the system to see if there are leaks. He goes son to say, "...any leak behind MAF will cause a major rich condition under load, as that metered air might be escaping but still being counted as fuel.

My tuner also tells me that plug gap is critical. My current gap is .039; whereas, he suggests that plug gap should be ~.025. Although not desirable, I need to remove spark plugs again and set the gap to his specs.

Again, thanks for your guidance and advice.

regards,
John Barnes
 

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My car is supercharged as well, but it’s a Coyote engine. My plugs are gapped at .032 . I think you may have an air leak, as well. Did you install this yourself, or is it a shop install?
 

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Discussion Starter · #5 ·
Thanks for the response.

I installed the ProCharger kit myself. Sorry... when you say, "you may have an air leak," what does that mean? Are you suggesting that there's a leak in the forced induction system?
 

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I’m suggesting you may have unmetered air entering the engine. It’s common unfortunately. If you want to be sure, I’d do a smoke test and see what happens.
 

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Discussion Starter · #7 ·
I've pressure tested the system and found no obvious leaks. Does anyone else have any ideas? This was my first post on a forum like this. I was hopeful that there would be more feedback.
 

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I can’t help that more responses haven’t materialized. Sorry about that. It seems you are in the New York area and unless I’m mistaken, there are some quality Mustang performance shops. Also, you didn’t mention if you did any datalogging to capture a readout of parameters while the engine was faltering. I would expect that a good tuner could read your data log, and get clues as to the failure. I’ll see if I can get a response from someone that has experience with centrifugal superchargers. I do know a Tech-Expert who my have something to add.
 

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Discussion Starter · #9 ·
Yes, I am located just outside of Rochester, NY. I do have a reputable tuner working on the car. However, I have not yet done any datalogging to capture any valuable parameters. Today, I installed an Innovative wideband AFR gauge to get some visibility into the AFR when the engine is faltering. Thanks again... I do appreciate your swift response.
 

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Yes, I am located just outside of Rochester, NY. I do have a reputable tuner working on the car. However, I have not yet done any datalogging to capture any valuable parameters. Today, I installed an Innovative wideband AFR gauge to get some visibility into the AFR when the engine is faltering. Thanks again... I do appreciate your swift response.
I made a mistake when I first went with Forced Induction. I thought the tuner (who is beyond renowned in this part of the US) could help fix a post-install issue similar to yours. The mistake was that I didn’t realize that just because you are a great calibration expert, doesn’t mean you are a great diagnostician, or mechanic. As hard as he tried, my tuner couldn’t figure out my problem (he had the car for several days trying).

I finally broke down and did some research to find the most performance friendly Ford dealership, with a good reputation for repairing Mustangs. It turned out to be the dealer closest to my house. I drove over to TALK to the service advisor who handled Mustangs. He understood, and set me up with the regional factory trained tech that does all the diagnosis and repairs to the Ford GT cars (GT40’s etc). I had to wait a week to see this tech for diagnosis, but it went like this…

I pulled my Mustang into the service isle. The service writer already had my paperwork in hand. He escorted me to the waiting lounge, where I brewed a cup of coffee. Ten minutes later (TEN), the service writer came into the lounge and told me the diagnosis was completed, and the problem identified. I asked what the problem is, and he said it was a faulty wiring harness connector at the Crankshaft Position Sensor. Just that quick, $150 was spent. He then asked if I wanted it repaired, to which I wanted to say DUH! He told me the repair would cost an additional $150, but it was guaranteed to fix my problem and if it didn’t I would be charged for anything. I told him to fix it, and it took 15 minutes to complete, and pull the car back into the isle for pickup. I was happy to spend the money.

They 100% fixed my problem easily (and took photos of the damaged harness as well as the repair). After that, I realized that for all the hate people assign to dealerships and their technicians, some of them are REALLY good at their jobs. It was money well spent.

The moral of the story is this, tuners are good at tuning cars that don’t have any mechanical or electrical issues. You may need an actual diagnostician to assess the problem, and get this fixed quickly.
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Discussion Starter · #11 ·
I made a mistake when I first went with Forced Induction. I thought the tuner (who is beyond renowned in this part of the US) could help fix a post-install issue similar to yours. The mistake was that I didn’t realize that just because you are a great calibration expert, doesn’t mean you are a great diagnostician, or mechanic. As hard as he tried, my tuner couldn’t figure out my problem (he had the car for several days trying).

I finally broke down and did some research to find the most performance friendly Ford dealership, with a good reputation for repairing Mustangs. It turned out to be the dealer closest to my house. I drove over to TALK to the service advisor who handled Mustangs. He understood, and set me up with the regional factory trained tech that does all the diagnosis and repairs to the Ford GT cars (GT40’s etc). I had to wait a week to see this tech for diagnosis, but it went like this…

I pulled my Mustang into the service isle. The service writer already had my paperwork in hand. He escorted me to the waiting lounge, where I brewed a cup of coffee. Ten minutes later (TEN), the service writer came into the lounge and told me the diagnosis was completed, and the problem identified. I asked what the problem is, and he said it was a faulty wiring harness connector at the Crankshaft Position Sensor. Just that quick, $150 was spent. He then asked if I wanted it repaired, to which I wanted to say DUH! He told me the repair would cost an additional $150, but it was guaranteed to fix my problem and if it didn’t I would be charged for anything. I told him to fix it, and it took 15 minutes to complete, and pull the car back into the isle for pickup. I was happy to spend the money.

They 100% fixed my problem easily (and took photos of the damaged harness as well as the repair). After that, I realized that for all the hate people assign to dealerships and their technicians, some of them are REALLY good at their jobs. It was money well spent.

The moral of the story is this, tuners are good at tuning cars that don’t have any mechanical or electrical issues. You may need an actual diagnostician to assess the problem, and get this fixed quickly.
View attachment 304598
Thanks for taking the time to share this story with me. I work in the information technology field as a solutions architect. Sounds fancy, but my jobs is to design solutions to solve problems. At the heart of the role is identifying a concrete problem statement. Once you know what the problem "IS," and identifying the root cause, then and only then can you develop solutions. Thanks for taking the time to showcase "what" is important. I will do my homework and get it into the hands of someone that can diagnose the problem, for which I don't have root cause.

She's not a Rousch, but she is all mine.
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It's easy to go down the rabbit hole here. Engines need fuel, fire and air in the right time to make power. I concur here that the two basic suggestions of an air leak and gap too wide need to be explored but, you would not be ill-advised to strap the thing to a dyno, even hook up a scope (if you can find someone who knows how to work one these days) and try to map the problem out. Even a dyno alone can reveal tuning problems, spark blowout, lean/rich conditions, timing scatter and other problems. This allows a diag without the risk to life and limb that doing it on the road brings. Datalogging the condition could also really help, if you've got an SCT or similar that can do that. I don't think plug heat range is the issue. You want to run the hottest range it'll stand without melting or causing pre-ignition. Plus you note the problem is present when there isn't much heat in the plug. You can't use tail pipes to gauge anything. Exhaust flows the way it wants, cools how it wants and deposits where it wants. The spark plug tells you the real story. A good old fashioned plug chop isn't a terrible idea either, iow, wail on it and turn the ignition off, then pull the plugs and look.
 
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