What will running A/F to lean do to the motor?

[2k05gt]

This weekend our local Mustang Club had a Dyno Day, for 50 bucks you get two pulls and they would adjust the A/F.

I had a JLT II CAI installed a month ago and I got a Canned tune from V-8 Power (where I purchased my SCT II Tuner From). Anyway, It was my turn on the Dyno and they strapped my car down like it was a crazed horse, put probs in a few orifices and fired her up, the 27 inch flat plasma screen sparked to life with numbers and dials, every mash of the gas pedal the numbers surged, then the tuner yelled out, "Shut Her Down!!" un strap this car. I was amaized that I did not get my dyno readings. the tuner walked over to me and said, " she's running too lean your over 18 A/F ratio, I would not drive this car home" I was dumfounded, I said that V-8 Power.com gave me the tune for the JLT and I have not had any Check engine lights or codes show up. He turned and looked straight in to my eyes like a crazed trainer who values each horse as his own and said, If I can make one thing clear, You can not Tune a Car Over the Internet" he turned and walked away.
So I walk into the office to talk to the owner and he wants to make an appointment for a Dyno Tune in three weeks. He stated that
"The Air fuel was checked after the cats through the exhaust pipe and reading after the cats is always leaner, but 18 can severly damage your engine" so he recommended that I put a stock Intake back on and flash the PCM back to stock to drive home.

So I go back to V-8 Power to find out why they messed up my tune. the
The only items I have on the car are as follows:
JLT II CAI
62mm Throttle Body by Granatelli Motor Sports
Steeda Underdrive Pullies
MAC Axle-Back Exhaust.

V-8 Power sends me a new file, do I trust it, and run next week at the track?
or cancel until the Dyno Tune before Drag Racing

The one question still remains un-answered, What damage could I have done driving the car for a month that lean????????

 

[2k05gt]

Well I guess it either a tough question or a stupid one,

Here is what I do know about running lean...
Running lean will burn plugs up.
Can burn valves.

But my question What Damage if any could I have done in a months time.
(about 600 miles)

 

[Steves06GT]

Honestly, I would take it in to another dyno for a second opinion. An 18 a/f ration is lean enough to blow your motor inside of 50 miles, let alone 600. Take it somewhere else and explain the situation and have them check it. I bet the first place had something wrong or incorrectly set in there equipment.

 

[2k05gt]

could I get just the air fuel reading done at an emissions station, I do not know of any other Dyno shops in the area.

is there a Wideband A/F guages that will work in the same hole as the stock O2 sensor or do I need to have a new hole welded on before the cats

why would A/F ratio @ 18 blow the motor in 50 miles?

I had V-8 Power redo my file compleatly should I trust it?

 

[Steves06GT]

an a/f ratio of 18:1 is CRAZY lean. Try and google 'DYNO' in your local area, I did it and found quite a few I had no idea where near me.

 

[TGJ]

What tuning software does this dyno use? I am willing to bet your car is not that lean and they are trying to sell you a tune.

Is your engine pinging and knocking? Do you have CEL( Check Engine Light )? Your car will have both of those issues present if your car is truly that lean. You would have lost your motor by now. My cousin got the wrong Diablosport Predator for his Steeda CAI and was that lean, he didn't last as long as you did before he lost a piston.

 

[2k05gt]

What tuning software does this dyno use? I am willing to bet your car is not that lean and they are trying to sell you a tune.

Is your engine pinging and knocking? Do you have CEL( Check Engine Light )? Your car will have both of those issues present if your car is truly that lean. You would have lost your motor by now. My cousin got the wrong Diablosport Predator for his Steeda CAI and was that lean, he didn't last as long as you did before he lost a piston.

I do not know what dyno they use, Can you tell by the Dyno sheet? I had this dyno tune done when I got my K&N CAI and 62mm Throttle Body in December.

http://home.comcast.net/~swieduwilt01/Cars/dynorunc.jpg

I do trust these guys, I had a tune done there already, Plus I was there looking at the screen, in big numbers @ idle A/F 17.9-18.1 when he revved the engine it dropped to 17.1 and there was about 10 people there waiting for the same thing, It was a Dyno Day for our club

I had no engine knock or CEL, I did get a CEL when I first installed the JLT II but I asked V8Power for a new tune and since then no problems

 

[SP_51-F1]

Pull a spark plug and look at it. If you have been driving with that tune for 600 miles, it will show what is going on inside your engine.

 

[cleveland]

yeah... There is no way in hell your motor could be running that lean without a Check Engine OBDII Code showing up in your gauge cluster. Hell, you'd probably get a Fail Safe Mode at 18:1.

That tuner was just ignorant, something just wasnt hooked up right at the time. What a waste.

-Dan

 

[killertomato]

2k05gt how did this turn out for you? I noticed that the place was where I'm planning on taking my mustang to for tuning.

 

[Chad_Diesel]

My car has the C+L cold air intake w/ the C+L diablo tune. It runs at 13:1.

 

[red05bullitgt]

Although, I'm miles away from being, what you call, a dyno or tuning expert..However, I agree with the other members, hands down..And if your car, was really running at 18.1 A/F ratio..For one thing, you would notice knock and pinging, like crazy..Then on top of that, your check engine light would also be flashing, if not staying on..And if that isn't enough, It doesn't take a rocket scientist, to figure out, that the car would be almost guaranteed, to end up going into fail safe mode or even worse yet..You would have definitely, ended up frying your pistons, if you had been runing 18:1 A/F for as long as you have.. by now, for damn sure..So, I agree 100%.. This tuner, was trying to take you, for one hell of a ride..And he was full of nothing, but..