'03 Cobra Pinging

AmdMAN

Founding Member

Jul 21, 2001

849

0

0

Kentucky

May 13, 2006

#1

• May 13, 2006

• #1

Hey guys,
I took the Cobra I planned to buy out on a test drive today. Took off fairly quick no issues, etc. Got on the highway had the car under load in 5th gear and heard some pinging. Come to find out some wrench monkey at the car dealer put in 87 octane gas. I guess its pretty decent 87 because it didn't ping until that engine was under HEAVY load. Sooo my question is, how much pinging can an engine withstand before real damage is done? I didn't know what it was so I had stepped on it a few times (only two where I heard that) before we narrowed the problem down. Think it could have done long term damage? The engine idling seems fine although now a belt is making some noise (squeaking) but besides that the car is in top shape. Deciding whether I should get it or not.

 

M

midlifecrisis99cobra

Founding Member

Jun 2, 2000

420

0

16

Plano,Texas,USA

May 13, 2006

#2

• May 13, 2006

• #2

My thought is that the car is probably OK. The forged bottom ends are pretty tough. The computer will pull timing when the knock sensors light up. As for the tech, what a nimrod.

 

U

Uncle Meat

Banned

Jun 13, 2002

0

1

0

Prattville, Alabama

May 14, 2006

#3

• May 14, 2006

• #3

Hard to say really... The upper ring lands are what get damaged by excessive pinging on these cars. The top ring land on the stock pistons is the weak point and if there's going to be damage it would be visible there. You may want to have them perform a compression & leak down test on the motor.

U.M.

 

T

tom's_03SVT

New Member

Apr 2, 2005

35

0

0

SOCAL

May 15, 2006

#4

• May 15, 2006

• #4

maybe the dealership put in the wrong gas...

 

281pony

Active Member

Aug 31, 2003

2,681

2

46

Oly, WA

May 15, 2006

#5

• May 15, 2006

• #5

he said they put in 87.

as far as the car, i would have them inspect it fully and take note of the pinging before any purchase was made. if that checks out, go for it

 

SVT98Snake

New Member

Apr 15, 2005

258

0

0

OK, USA

May 15, 2006

#6

• May 15, 2006

• #6

well der....87 is your problem.

sounds like tip-in too.

You can cause severe oil consumption issues detonating at low RPM in the upper gears under load....geeze. I hope you didn't do that for long.

If you buy it, flush it out, put some 93/101 blend to be safe and let it run it's course....

 

AmdMAN

Founding Member

Jul 21, 2001

849

0

0

Kentucky

May 15, 2006

#7

• May 15, 2006

• #7

I have them performing a compression and leak down test on it. We will see what they come up with.... Anyone have the specs of what I can consider acceptable norms for those tests?

 

hotmustang331

Active Member

Apr 29, 2004

2,967

3

48

Bastrop,TX

May 16, 2006

#8

• May 16, 2006

• #8

If im not mistaken, 03-04 cobras dont have a knock sensor....just an AIT sensor that pulls timing dependant on air temps. Stock terminators are tuned pretty safe (note that you can gain freegin 40RWHP JUST from a tune)..low timing, rich AF. As long as it didnt ping @ WOT under alot of boost, it should be ok.

 

xseler8

Member

May 4, 2004

619

0

17

Montgomery County,Pa.

May 16, 2006

#9

• May 16, 2006

• #9

Request an extended warranty with the purchase(if you buy it). It was traded for a reason.Hopefully it the owner was upgrading-not trading it in because of problems.

 

AmdMAN

Founding Member

Jul 21, 2001

849

0

0

Kentucky

May 16, 2006

#10

• May 16, 2006

• #10

Well I guess I was wrong..... They had the car for an extra day today (waiting on the broken spoiler lens) and they figured out what the noise I heard on the highway at low RPM's in 5th gear was..... At first I thought it was the exhaust rattling, but then they spoke of 87 octane so thats what I figured it was. Turns out it was a bad transmission mount they found today and are in the process of replacing it today. I don't recall hearing any other issues so maybe the car wasn't detonating at all.. Hell I don't know, I have never had a car detonate before.

 

COBRA90GT

Mustang Master

Sep 22, 2001

6,654

0

87

HOCKEYTOWN ® , MI

May 17, 2006

#11

• May 17, 2006

• #11

AmdMAN said:

...I have never had a car detonate before...

Click to expand...

Similar to the sound of marbles bouncing around in a coffee can. Not good.

 

U

Uncle Meat

Banned

Jun 13, 2002

0

1

0

Prattville, Alabama

May 17, 2006

#12

• May 17, 2006

• #12

AmdMAN said:

Turns out it was a bad transmission mount they found today and are in the process of replacing it today. I don't recall hearing any other issues so maybe the car wasn't detonating at all.. Hell I don't know, I have never had a car detonate before.

Click to expand...

Let's hope that's really the problem and not just some story they concocted to keep you interested in the sale. We all know how honest and loyal car dealerships are...

U.M.

 

AmdMAN

Founding Member

Jul 21, 2001

849

0

0

Kentucky

May 17, 2006

#13

• May 17, 2006

• #13

Uncle Meat said:

Let's hope that's really the problem and not just some story they concocted to keep you interested in the sale. We all know how honest and loyal car dealerships are...

U.M.

Click to expand...

I agree with you, but this is Carmax, I don't know if you have dealt with them before, but they actually told me someone had put 87 in it, I would think most wouldn't have said that and made something else up. Like someone else said here though, I can always get the extended warranty which isn't expensive which leaves everything on their dime. It did sound like a rattling more than marbles and it sounded like it was coming from under the car not in front.. I will drive it again probably today as well as get the CT and LDT results.