Detonation problems

F

Ferris Bueller

New Member

Feb 4, 2003

21

0

2

MD

Feb 26, 2004

#1

• Feb 26, 2004

• #1

I'm hunting down a pre-ignition problem and was wondering what else to check.

Symptoms:

Whenever i'm in 4th or 5th gear and I give it a lot of gas at lower RPMs, it pings slightly. The pinging goes away when I lighten up on the gas and accelerate more slowly.

Louder pinging under hard acceleration in second gear from 4000 RPMs and higher.

Pinging only occurs under these conditions when the engine is at operating temperature. No pinging under load until temp guage reaches normal range.

What I have tried:

Checked plugs: Bosch plugs seemes a little whiter than i'm used to, but not signs of damage.

Replaced fuel filter: Previous filter was on backwards

The car has 77K miles on it. Mods are in sig. Always use 93 octane gas.

 

H

hioc1098

Founding Member

Aug 18, 2002

76

0

0

Rome, NY

Feb 26, 2004

#2

• Feb 26, 2004

• #2

Do you think you might be running too much timing? I'd back the timing off a little and see what happens. You may have some bad gas.

Also, check the gap on the timing adjuster. If it's too loose, it'll detonate.

Tim

 

H

hioc1098

Founding Member

Aug 18, 2002

76

0

0

Rome, NY

Feb 26, 2004

#3

• Feb 26, 2004

• #3

After looking at your sig again, I don't think it's timing. I used to run 14+ with no issues. Check the gap on the timing adjuster.

If you're running Bosch Platinum 4s, I've heard of people having issues with them. Whiter plugs is a sign of the car running lean.

Tim

 

F

Ferris Bueller

New Member

Feb 4, 2003

21

0

2

MD

Feb 26, 2004

#4

• Feb 26, 2004

• #4

Is it possible the plugs are too hot for the raised compression due to the headswap? I'm asking this since the problem seems to correspond with engine operating temperature and not outside temperature. Thanks.

 

2

2002BLGT

Well-Known Member

Dec 18, 2003

2,945

4

59

Bedford VA

Feb 26, 2004

#5

• Feb 26, 2004

• #5

put in some autolite 764s and gap them at .045 , see what that does , if still pinging , drop timing back to 10 degrees

 

R

Ryan L

Founding Member

Apr 15, 2001

783

0

16

St. Augustine, FL

Feb 26, 2004

#6

• Feb 26, 2004

• #6

I didn't read all the responses, but try this first.

93 Octane
stock timing
stock COPPER plugs (TR-55s, Autolite 764s, etc)
Clean MAF sensor

That should do it. If it works, then slowly bump up timing.

 

2

2002BLGT

Well-Known Member

Dec 18, 2003

2,945

4

59

Bedford VA

Feb 26, 2004

#7

• Feb 26, 2004

• #7

yea definitely clean the MAF sensor too . forgot about that .

 

Hissmann

Founding Member

Sep 5, 2002

243

0

0

West Virginia

Feb 26, 2004

#8

• Feb 26, 2004

• #8

What is the safest way to clean the MAF?

 

F

Ferris Bueller

New Member

Feb 4, 2003

21

0

2

MD

Feb 26, 2004

#9

• Feb 26, 2004

• #9

I forgot to mention that i already cleaned the MAF sensor. The screen and the sensor wires were coated with a black dust. I removed the air box and screen and used a q-tip to carefully brush off the dust off the two sensor wires. I've heard that some people use electrical contact cleaner on the q-tip since it leaves no residue.

Another way to remove the MAF sensor is to undo the two torx bolts on the top of the sensors on the inlet tube. The whole assembly can them be raised out of the inlet, making the sensors easier to get to.