2010 gt hot rod cam sputtering issues

[Gotyoumad757]

As the title states,
I have a 2010 gt and had my hot rod cams installed today. Install went well, professionally done. I have the sct x4 with 2 tunes for my setup (hot rods, off road x pipe, 3.73's and air raid cai), an 87 octane and a 93 octane from bama. I also have 2 tunes for the same octanes from lito, and got the same sputtering while driving under load. Car has 62,400 miles and is well taken care of. I tried all 4 tunes from both bama and lito, although the lito tune did much better the sputtering was still there and made driving the car pretty sketchy. No codes appeared after a 30-40 min ride. Any help is most appreciated. Ideas?

 

[46addict]

Mileage on the engine? Status of spark plugs, plug boots, fuel filter, and has the throttle body been cleaned?

 

[RocketcarX]

MY mutha thumprs sputter below 3k sometimes, its fairly mild but I can hear it in the exhaust, going full throttle makes it go away...may only be so much that can be done to cure it considering the duration of the cams.

 

[Gotyoumad757]

Mileage on the engine? Status of spark plugs, plug boots, fuel filter, and has the throttle body been cleaned?

62,400 and it ran fine before the cam swap, I am gonna get some new plugs tomorrow. And nothing out of the ordinary with the throttle body, I will also verify and clean it in the morning as well.

MY mutha thumprs sputter below 3k sometimes, its fairly mild but I can hear it in the exhaust, going full throttle makes it go away...may only be so much that can be done to cure it considering the duration of the cams.

This sputtering is bad enough to where I wouldn't dare put my foot down.

 

[Dino Dino Bambino]

You could do some data logging and send the file to Lito so he can update the tune.

 

[Gotyoumad757]

You could do some data logging and send the file to Lito so he can update the tune.

If im lucky he will work with me on a sunday

 

[sman247]

if you notice a difference after changing the tunes it most likely a tune issue. I had the same sputtering with your same setup years ago, tried changing every thing and nothing worked. Only fixed the issue once I got it dyno tuned. But as stated above, check all of the usual maintenance suspects just to make sure.

 

[Gotyoumad757]

yeah I agree. Just trying to get any tips/info possible. Im going to the auto parts store to get some new plugs now

 

[702GT]

By sputtering do you mean like small backfire? Or more like misfire? When dealing with tight LSA's, it's possible to have over-fueling at low-rpm. While O2's and wideband's read A/F ratios fairly well, raw fuel not so much. With tight LSA's, the exhaust valve is still open as the intake valve is flowing. This promotes momentum in air velocity, helping to not only draw air in via the piston stroke but also through the exhaust. Often it also drags raw fuel as well as fresh air into the exhaust. The fresh air is more easily read by the sensors than the raw fuel, which can be misleading. Because it reads a lean condition, more fuel is added, which causes over-fueling, and then you start to get minor backfires or even misfires if the cylinder is rich enough to saturate the spark plug. The only time you really want to see fuel in the form of carbon on the plugs is during WOT/load. When idling/cruising, the cylinder should be lean to promote natural carbon cleaning of the plugs. I would say take a fresh set of plugs, or clean the existing thoroughly, and then idle the car up to temp. Pull the plugs and read them. If they're getting fuel buildup, it's likely as I stated, over-fueling. NA cams can be tricky to tune for drivability and efficiency. When I had the 127020's I always had a bit of backfire/misfire at idle and low rpm. Around 2,000-3,000rpm where I cruised, it was fine. There was enough airflow and heat the motor ran more efficiently. WOT was, of course, perfect because it's closed loop. I would say mild backfire/misfire is normal for an imperfect tune of a tight LSA cam. The tune can be perfected, just need a tuner that knows what needs to be done and spend some time with it. If it's more than a mild backfire/misfire, then there could be other issues (I had an injector that was leaky/sticky, and a bitch to trace down. Bought a rebuild kit and followed a youtube video and cleaned/rebuilt all 8 injectors, no issues after that).

Edit: Also important, if there is a consistently rich condition or over-fueling, it's possible to foul the O2 sensors to where they aren't reading accurately. Because they aren't accurate, they can lead to additional inaccuracies in fuel trims. There are methods for de-fouling the sensors, but most are sketchy. It's always handy to have a separate set of good O2's for tuning/datalogging, so these inaccuracies can be eliminated. If the tune is too rich, it'll foul the good O2's as well over time, leading you back to square 1. So if you do get another set, use them strictly for tuning/datalogging purposes.

 

[07 Boss]

As the title states,
I have a 2010 gt and had my hot rod cams installed today. Install went well, professionally done. I have the sct x4 with 2 tunes for my setup (hot rods, off road x pipe, 3.73's and air raid cai), an 87 octane and a 93 octane from bama. I also have 2 tunes for the same octanes from lito, and got the same sputtering while driving under load. Car has 62,400 miles and is well taken care of. I tried all 4 tunes from both bama and lito, although the lito tune did much better the sputtering was still there and made driving the car pretty sketchy. No codes appeared after a 30-40 min ride. Any help is most appreciated. Ideas?

There is your problem right there. Do some data logging for Lito and don't deal with Bama any more.

It is funny though how everybody wants a shitty idle as long as it's not too shitty. Kinda like tinting headlights and wondering why they can't see at night.

 

[redfirepearlgt]

There is your problem right there. Do some data logging for Lito and don't deal with Bama any more.

It is funny though how everybody wants a shitty idle as long as it's not too shitty. Kinda like tinting headlights and wondering why they can't see at night.

"You're killing me Smalls" -- Sandlot, The movie

 

[46addict]

The best time to read plugs is when you're at the dragstrip. That way you can shut down the engine at the finish line, coast to a stop, pull over to a safe spot, and read them right after a nice 1/8th or 1/4 mile WOT pull. A long amount of idle or crusing time will skew the plug reading. Just throwing this out there.

Lito tuned my car when it had a very similar setup as the OPs and it was spot on in many ways. It even got 22mpg highway with 3.73s. My only complaint is that cold start was a bit rough and it needed a 30 second warm up before driving away.

 

[Heaten m90]

My old hot rod setup Would have mild instability at 3k RPM under 60% percent throttle. I chalked it up to the cams geometry. The issue persisted with various tunes, coils, tb’s and 39&80LBS injectors.

 

[RocketcarX]

The best time to read plugs is when you're at the dragstrip. That way you can shut down the engine at the finish line, coast to a stop, pull over to a safe spot, and read them right after a nice 1/8th or 1/4 mile WOT pull. A long amount of idle or crusing time will skew the plug reading. Just throwing this out there.

Lito tuned my car when it had a very similar setup as the OPs and it was spot on in many ways. It even got 22mpg highway with 3.73s. My only complaint is that cold start was a bit rough and it needed a 30 second warm up before driving away.

God I hope mine improves once he starts getting my revisions done because I'm averaging 12mpg and the car is an absolute dog out of the hole. To be honest I'm a little disappointed in the length of time the tuning process is taking. My tune I built in HP Tuners made a lot more top end power. Patience is a key I suppose, I'm just ready to spray this thing and I'm getting tired of missing races.

 

[46addict]

I know the feeling. He writes tunes for people around the world and not just for us in America. And he may not have reliable internet service like we do. But it will get done.

 

[RocketcarX]

I know the feeling. He writes tunes for people around the world and not just for us in America. And he may not have reliable internet service like we do. But it will get done.

I made some pretty specific datalogs today instead of one long one. I sent them over, hopefully that helps. I got my wideband working again and wired into the SCT X4, added the PID so it could be included in the logs. I think that will help speed things up, I know he’s a busy guy.

 

[Totheboards]

Pretty much the same setup here. Low RPM drivability was sacrificed for a mild improvement at top end. Pretty much anything over 1500 rpm purrs smoothly for me though... All in the tune.

 

[EBABlacknChrome]

I made some pretty specific datalogs today instead of one long one. I sent them over, hopefully that helps. I got my wideband working again and wired into the SCT X4, added the PID so it could be included in the logs. I think that will help speed things up, I know he’s a busy guy.

Lol. I said that to lito 2 nights ago his response was priceless! He's in Spain and theirs fiber connections everywhere internet's fantastic a whole lot cheaper and in America we're getting hosed. Lol.

Sent from my SM-G930V using Tapatalk

 

[lito]

God I hope mine improves once he starts getting my revisions done because I'm averaging 12mpg and the car is an absolute dog out of the hole. To be honest I'm a little disappointed in the length of time the tuning process is taking. My tune I built in HP Tuners made a lot more top end power. Patience is a key I suppose, I'm just ready to spray this thing and I'm getting tired of missing races.

Are you Casey?

 

[RocketcarX]

Are you Casey?

Yessir