This is why I'm getting a new tune

[Ande99SVT]

Not sure if you guys remember but awhile back I began having problems with the car after a new and "improved" tune was put on it.


So after a month or so of losing gas mileage and the car dying after hard WOT pulls, I finally took it in to get it dyno'd by another shop.

Check out the A/F, just one of the problems they explained to me about the tune.

So this Friday she is going down to get cleaned up. Also need a new belt as I can finally see that she is slipping up top.

 

[TVS VERT]

very surprised u didnt melt a piston.....actually surprised u didnt melt all 8....im very surprised the dyno operator/tuner allowed car to do a full run with it that lean

 

[cj428mach]

very surprised u didnt melt a piston.....actually surprised u didnt melt all 8....im very surprised the dyno operator/tuner allowed car to do a full run with it that lean

Ditto, how your motor isn't toast is unbelievable.

 

[JRS03]

DAMN!!!! they should have let off as soon as they seen it go lean.. You sir are very lucky.

 

[JRS03]

Who are you going to have tune it?

 

[Chosyn1]

Holy ****ing shit man.

This post was edited by moderator. Do not bypass the profanity filter!

 

[Cobra03SC]

That person on the dyno probably did some serious damage to those pistons. There is no excuse for continuing a pull to 6k+ when its that lean the entire way. I would check those pistons out before i even went in for a new tune.

 

[TVS VERT]

if this car has had this tune for any amount of time and hasnt melted anything yet im thinking they dyno's wideband or tail pipe siffer is off by a good amount, as there no way that car should still be rotating, theres times its close to 13-1 A/F and 21 psi from a 2.2 KB is a very healthy dose of boost.

Best of Luck my friend, get it dialed in.

 

[jetmech]

Yeah I wouldn't say you made it out of the woods after that run. I would have you engine checked out. The guy operating the dyno has no idea what he's doing if he saw how lean your car was during the run, he should have let off immeadiatly. I'd say he owes you a motor.

 

[50q's]

You need to get that motor looked over.

 

[Ande99SVT]

The shop I took the car to to get dyno'd at is a very reputable one and the tuner there has tuned just about everything. While I was there they had a twin turbo Cobra build, single turbo Cobra build, LS1 swapped 66 corvette, an Aston Martin, and two GTR's. I have faith in their tuner and the rest of the shop to tell me if the car needs to sit or can be driven. The car is only on 15 pounds and compression check is good. The boost spike was due to a slipping belt. I'm going to have this car cleaned up this Friday and it should be.

 

[Ande99SVT]

And in no way am I trying to bad mouth you guys I honestly appreciate it when you guys take the time to rely. what should my A/F be at?

 

[cj428mach]

And in no way am I trying to bad mouth you guys I honestly appreciate it when you guys take the time to rely. what should my A/F be at?

About lower to mid 11's. As it goes into higher 11's you get nervous then anything over 12 = blown motor. Thats why people assume yours is junk.

 

[itSSlow98]

Looks like the tuner thought he was tuning a naturally aspirated car. I still can't believe a shop would make a full pull that lean on a boosted car. Compression check is only 1/4 of the test. You should do a leak down.

 

[Ande99SVT]

About lower to mid 11's. As it goes into higher 11's you get nervous then anything over 12 = blown motor. Thats why people assume yours is junk.

So although the car itself has been running fine and the power is still there, the car could essentially be shot?

 

[joel3431]

It's possible you have done some damage (I hate so tell you that) Best thing to do it is drive as little as possible. None if you can until it goes on the dyno again, give them that chart so they know they need to increase fuel across the board if the tune on it now can be adjusted. If it's locked or they go with whatever their base is, you should be good to go. I would run a compression test just to be safe. (It could be perfect with not a scratch really depends on how much you've got on it, and your luck.)

Not to ruin your day with a bad story but I had my old 98 cobra tuned (Novi 2000 and some stuff) guy tuned it around 12.5-13.0 had no idea what he was doing. I took back 3-4 weeks later to another guy with a dyno to get it checked, first pull not much into it at all reading real real lean. I drove it enough to start eating a whole in the piston, after I got the tune fixed (correct A/F) it lasted 3 days until the hole made it through the piston and I started it up, fuel filled the pan and the spark made one big boom. Bam blew out all my seals and blew my entire valve cover apart, like 20 pieces. I pooped my pants a little. Lol

 

[Ande99SVT]

Does it matter where the A/F was read?

 

[vladSVT]

I hope you didn't do alot of pulls on this tune, as its a shitty one at that.

I doubt that the tuner hurt the motor since the air fuel is not THAT lean (yes around 12.5-13.0 is lean but its not enough to cause immediate damage IMO). However anything is possible and there might be damage and you might not even know it.
But I do agree that there is no need for ANY tuner to pull it up to 6K if the car is going lean. You see it going lean, let out right away don't stay in it.

Change the plugs asap and get a wideband

 

[Cobra03SC]

Does it matter where the A/F was read?

The wide band they put into your exhaust reads the A/F during a pull. Anything over 12 is way too lean for a boosted car. You want to see a nice smooth line between low and high 11s. What potentially could happen, and may have happened is your piston and rings will slowly get melted away and a hole will form. Really the only way to check will be a comp test and leek down like suggested. I had 1 of my pumps go bad during a pull and still had a 12.5 a/f and it still did this:

Hopefully the wide band they were using is off, if not there's and pretty high chance you have at least some damage.

 

[Ande99SVT]

Thanks guys, I'll be throwing the tune back on the car that it had when I first got it. It was running 10.8 A/F through the entire pull but that seems a hell of a lot safer than this one. Friday she will be getting a fresh one. I'll also look into getting a leakdown and compression check also.