New to me 2002 LS V6 with a lot of ignition knock.

A

atikovi

Active LVC Member
Joined
Aug 30, 2006
Messages
75
Reaction score
0
Location
Suburban Washington DC
Recently got the car so I don't know what gas is in the tank but even if its 87 octane, it's still pinging too much. Once it's warmed up, even slight acceleration will cause it to knock. It has no codes stored and has over 150,000 miles. Could it be carbon build up?
 
87 octane will not help because this car requires premium (at least 91)
Did you ask the previous owner if what kind of gas he's been using?
 
using premium will get rid of that knock, if the knock sensor could handle it then it might just say "premium recommended" (i.e. bad gas mileage and power) but it's "premium required"
 
It's possible that the knock sensor is bad or loose, I'm not sure for how they mount. It could also be a bad or dirty MAF. If it sat for a while the gas in the tank regardless of octane rating will knock. The car will run on any grade, yes, premium is required, it will run on lower octane, if everything is working correctly it will just pull some timing. I would take it to any of the big box stores and get codes pulled, even if the CEL isn't on, it may have some stored codes.
 
atikovi said:
Recently got the car so I don't know what gas is in the tank but even if its 87 octane, it's still pinging too much. Once it's warmed up, even slight acceleration will cause it to knock. It has no codes stored and has over 150,000 miles. Could it be carbon build up?
Click to expand...
Follow the other suggestions listed including, cleaning MAF, EGR valve, check all O2 Sensors. Replace PCV system. Add octane booster or 91-93 octane if below 1/2 tank.
 
I drove it 20 miles after the fuel light came on and put in 5 gallons of 93. Makes no difference. If the EGR or O2 sensors were a problem I would think they would throw a code, no?
 
yes, get some octane booster!!!!!! I have the 01V6, runs like **** on 87! Fill with 91+, it will run great, no regular and no mid. Premium gas only
 
atikovi said:
I drove it 20 miles after the fuel light came on and put in 5 gallons of 93. Makes no difference. If the EGR or O2 sensors were a problem I would think they would throw a code, no?
Click to expand...

Usually.
Does your check engine light come on when you turn the key to run, before starting the engine?
 
I'm gonna play the Devil's advocate and ensure myself you've double checked your air breather element and fuel filter.
 
BigRigLS said:
I'm gonna play the Devil's advocate and ensure myself you've double checked your air breather element and fuel filter.
Click to expand...

Well, if you're going to throw that in...
Water in the gasoline will cause pinging too.
 
Just got the car. Haven't checked for anything but codes. And actually water in the gas may reduce pinging by cooling the charge. Water injection was common in the old days by hot rodders. I was going to change the fuel filter and the other maintenance items anyway. What would the fuel filter and breather have to do with knocking?
 
atikovi said:
Just got the car. Haven't checked for anything but codes. And actually water in the gas may reduce pinging by cooling the charge. Water injection was common in the old days by hot rodders. I was going to change the fuel filter and the other maintenance items anyway. What would the fuel filter and breather have to do with knocking?
Click to expand...

Water injection is different that water in the gas.
I've had pinging on my LS caused by gasoline contaminated with water. I'm not guessing here, I had it tested. (I thought they were selling 89 octane as 93, but the state tested and found that it was 93 octane, but it had a lot of water in it.)
 
atikovi said:
... What would the fuel filter and breather have to do with knocking?
Click to expand...

As I said "Devil's advocate" ... It's just a good idea to ensure other delivery items for the fuel/air are fresh and clean while troubleshooting.
PCM will make adjustments based on it's readings throughout. Slight pinging could also be a result of an improper air/fuel mixture.
MAF has to be clean and zero leaks throughout the intake.
 
Put in a new fuel filter. Odd location. Will do the plugs next. Right side looks like fun. I take it the intake runner has to be removed?

It looks like the hard plastic hose from the MAF to the throttle body was damaged at one time and glued back together to the thing in front of it. If it's leaking air, could that be a cause?

Also, at the top of the picture on the engine cover there is hole. Is there supposed to be retainer in there?

standard.gif
 
Is that a ty-wrap stuck through a hole at the front of the intake air chamber? If so, that's a leak that would be at least part of your problems.
 
No, that's the other end of the bungee cord. Been to a few junk yards and couldn't find that same part. What years should I be looking for? V6 only? The EPC shows two part numbers, 2W4Z-9B659-AA or 2W4Z-9B659-AB, any difference?
 
Parts from 2000 to 2002 V6 should work for you (there are exceptions, like the oil pump).
AB is the newer rev of the part, either should be okay for you but if the prices are the same I would go for the newer part.
 
atikovi said:
That's what I thought but none of the junk yard 00-02 cars looked the same and even my own 2000 is different.
Click to expand...
It doesn't have to look the same to function correctly. It just has to fit and work.
I wonder if what you have is some sort of modification that the previous owner made?
 
atikovi said:
Put in a new fuel filter. Odd location. Will do the plugs next. Right side looks like fun. I take it the intake runner has to be removed?

It looks like the hard plastic hose from the MAF to the throttle body was damaged at one time and glued back together to the thing in front of it. If it's leaking air, could that be a cause?

Also, at the top of the picture on the engine cover there is hole. Is there supposed to be retainer in there?

standard.gif
Click to expand...


Honestly, that silencer looks glued back on to me ... possible leak into system after MAF.

standard.jpg

get the whole thing out, clean it up, inspect all around including bottom side, ensure no cracks for air to enter.
With that bungee cord wrapped around it, tells me, it's being held in place for the time being but there is unmetered air entering in.


~ would you scrub and powerwash that whole underhood ordeal please? ... Clean engine is a happy engine. Looks Fn nasty I'm sorry to say.

standard.jpg
 
BTW - you could get away without that silencer from what I've read, take it off, smooth out the portion where it meets the intake tube, plastic weld a flat piece across it.

Note ~ it's been argued back and forth on whether it was a good idea or not, silencer's job is there to stabilize the incoming air waves from what I understood. Others have removed it without issue from what I read in previous older posts.
 
You must log in or register to reply here.

Members online

No members online now.
Total: 413 (members: 0, guests: 413)
Back
Top