Pinging/knocking

I have a 95 Sedan Deville and have had a knocking for 3 months. I took it to cadillac they said I needed a deep cleaning. I ran 3 tanks with BG-44 and I still have the probelm. It does not ping or knock when cold, when revving in neutral, in reverse with brake depressed or in park. Only when warm and in forward gears. I'm starting to think it could be my torque converter but I'm not sure. Any suggestions..........

My '97 Eldo ETC knocked occasionally. The dealer, and it's an excellent dealer with a top-notch service department, indicated it was common with the Northstars - carbon knock. I was always a little skeptical of that interpretation since my cars are exercised whenever the opportunity presents itself, which is frequently in this part of the country. That engine never needed to be blown out. The dealer ran cleaner through the engine which reduced the racket but didn't completely alleviate it. I never noticed any performance reduction and so ignored it going forward. The Eldo always ran like a top until we used it on a trade.

Have you received any feedback or find out what the problem could be? I have a 97 Eldo w/58k and does the same thing. Only when motor is warm. I run only premium Chevron and have tried different fuel and had teh dealer service the injectors, changed fuel filter. No explanation at this point. I take exceptional care of my car and am stumped! If you find a solution please let me know. Thank you

Old Jaguars had the same problem. Carbon build up would cause knocking. There are two ways to get rid of it. Remove and clean the heads or do the old water down the carb trick. The engine needs to be hot. It is a good idea to put some cardboard over the radiator to get the engine real hot. With the engine running trickle water into the carb or into the throttle on fuel injected cars. Keep the engine running while adding the water. Be careful not to add to much water at once or you could hydraulically lock your cyilinder and destroy the engine. It would probably take a lot of water to do that. So don't use the garden hose. The water explodes on the hot cardon and some how cleans it off. If you have ever seen a head off of a car with a head gasket leak you would notice how clean the cylinder with the leak was. I worked with a guy with a PHd from MIT , who had many engine pattents , a mad scientist, and he said the the water method worked.

Hello All!
I am inquiring if anyone has found a solution to the pinging/pre-ignition/detonation issue.
My 1996 Seville STS has 172,000 miles.  It has run perfectly for the six years I have owned it.
Six years ago I installed new wires, plugs and an EGR valve.
 
I moved from the North to Charlotte, NC a few days ago, and since then, the Northstar has caught a serious case of detonation.  It runs well, but sounds like it is going to blow any minute.
 
The outside temperature is in the 90s here which is about 15 degrees higher.  The temperature guage used to stay pointing straight up, but here in North Carolina where the weather is hotter the guage points to the first mark past straight up when at operating temperature.
 
So the car runs hotter now in the heat.  There is not any coolant loss. 
 
I have considered taking out the thermostat, or finding a way to turn on the cooling fans earlier in an effort to keep the engine cooler.  I have some fuel injector cleaner in the tank along with some 93 octane fuel.  Neither of those seemed to have helped yet.  I have always run 89 octane, but will run 93 or 94 for now on.
 
Could the crank position sensors be causing the spark to occur early?
Could the knock sensor have failed?  (if there is one)
Is it unusual for the temperature guage to move past half-way (straight-up)?
 
How do I stop the pinging?
 
Jon

your knock sensor is highly suspect.  i be parking this baby until you fix it or you will damage internals. 
you may also find some relief in the high octane fuels, but although it may allow you to operate it,
THAT is not a solution for this.   if the sensor failed, it may even ping even then.

your next problem is why is it running hotter?  ambient there does not justify that.
need to find out why.  however, i dont beleive that is a reason for the ping if the sensor is working.

quote:

ORIGINAL: jonrodman

Hello All!
I am inquiring if anyone has found a solution to the pinging/pre-ignition/detonation issue.
My 1996 Seville STS has 172,000 miles.  It has run perfectly for the six years I have owned it.
Six years ago I installed new wires, plugs and an EGR valve.

I moved from the North to Charlotte, NC a few days ago, and since then, the Northstar has caught a serious case of detonation.  It runs well, but sounds like it is going to blow any minute.

The outside temperature is in the 90s here which is about 15 degrees higher.  The temperature guage used to stay pointing straight up, but here in North Carolina where the weather is hotter the guage points to the first mark past straight up when at operating temperature.

So the car runs hotter now in the heat.  There is not any coolant loss. 

I have considered taking out the thermostat, or finding a way to turn on the cooling fans earlier in an effort to keep the engine cooler.  I have some fuel injector cleaner in the tank along with some 93 octane fuel.  Neither of those seemed to have helped yet.  I have always run 89 octane, but will run 93 or 94 for now on.

Could the crank position sensors be causing the spark to occur early?
Could the knock sensor have failed?  (if there is one)
Is it unusual for the temperature guage to move past half-way (straight-up)?

How do I stop the pinging?

Jon

it may be preventable.

read this:
http://www.cadillacforum.com/m_7154/tm.htm

quote:

ORIGINAL: 67SEDANDEVILLE

Old Jaguars had the same problem. Carbon build up would cause knocking. 

Hey Jonrod:  Something to think about. If you changed altitude very significantly when you moved you may require retuning of your engine, timing etc. Summer fuel is always an issue as well because they don't put in as many additives as is required for winter driving. The fuel will contain a higher percentage of water and hence change the burning characteristics of your fuel. Hope you can get the thing solved.

Hello brougham1 and Stealth,
 
Thanks for the good ideas.  I will put in a new knock sensor tomorrow. 
 
I have been occasionally doing WOT anyways.  Not as often lately, but I just drove 800 miles and did have the petal to the floor a bunch of times.
 
I did put on new spark plug wires yesterday.  That made a difference.  It idles smoother and is perkier.  Two or the wires appeared to have burned through and must have been arcing to the aluminum head at least intermittantly.  The new wires also seemed to have greatly reduced the pinging. 
 
The pinging is still occuring but not as much.  Tomorrow I will change the knock sensor and put in new plugs.  That  knocking has probably damaged one or more of the plugs. 
 
I actually cannot believe the engine has withstood the knocking.  It would have killed an ordinary engine.  I have kind or ruled out the higher operating temperature as being a problem.  It really  is not running much warmer than in the north, the cooling fans so come on when the guage reaches the first mark past half way.  The needle never goes anywhere near the red and there is not any  loss of coolant. 
 
I am at a higher altitude. 
 
If  the knock sensor does the trick, I will let you know.
 
Thanks again,
What a knowledgeable group!
Jon

Hey Jon
FYI
Remember that just putting the pedal to the metal is not necessarily our prefrered way of accomplishing WOT.  Click on link on the Stealth post if you haven't already.  We have discovered recently that on some sites WOT's are opposed, however their definition of WOT may be different then what we have posted.
 

 good point.   do read our  WOT link.
http://www.cadillacforum.com/m_7154/tm.htm

the WOT as defined in this web site is
pedal to the metal from a well defined low limit
to a well defined upper limit and then
FOOT OFF the pedal to a well defined LOW LIMIT
and repeats.

you got to stop the knocking or the engine will self destroy - but you know that.

keeps us posted

small print note:
none of this promotes or encourages spinning wheels, burning rubber, speeding, over-revs, or
other abuse that other web sites think is good - we dont agree with that philosophy.
Such behavior can damage not only the engines and transmissions,but may also do serious damage to the
personal ego with  either RED Lights behind you or getting home on a flat bed.

The saga continues,
So I took the 96 STS to the dealer.  They talked me out of the knock sensor replacement and charged me $600 for a diagnosis and to clean the throttle body, and for two bottles of z-max.  They told me it was fixed and I was happy to pay the $600.
 
My euphoria was brief because within 10 minutes of leaving the dealership, the engine warmed up and the spark-knock was back. 
 
So, I am out $600+ and my brand new Knock sensor ($60) is still sitting on the passenger seat, and the engine is still hammering away when it gets hot.  The weather is cooling down and the spark-knock is greatly reduced on the cooler days.
 
Installing the knock sensor is not as easy as I thought.  It is apparently located beneath the intake manifold.  I have to remove the engine cover, new stainless fuel rail, throttle body, EGR valve, and plastic intake manifold.  The only part of this that makes me nervous is the new stainless fuel rail.  I have never removed one before.  I know there is a specific tool to separate the fuel lines, but how do the fuel injectors disconnect from the fuel rail?
 
Yes, the dealer last week did replace the old plastic fuel rail with the stainless one, (recall) so they were that close to the knock sensor, but refused to replace it.  So now I have to dig in and replace it myself. 
 
Does anyone know what information a novice should know before removing the fuel rail?  Also, a list of tools may be helpful since I did not bring any tools with me, I will be making a few trips to Sears.
 
Thanks in advance!
Jon
 
 

quote:

ORIGINAL: jonrodman

Hello brougham1 and Stealth,

Thanks for the good ideas.  I will put in a new knock sensor tomorrow. 

I have been occasionally doing WOT anyways.  Not as often lately, but I just drove 800 miles and did have the petal to the floor a bunch of times.

I did put on new spark plug wires yesterday.  That made a difference.  It idles smoother and is perkier.  Two or the wires appeared to have burned through and must have been arcing to the aluminum head at least intermittantly.  The new wires also seemed to have greatly reduced the pinging. 

The pinging is still occuring but not as much.  Tomorrow I will change the knock sensor and put in new plugs.  That  knocking has probably damaged one or more of the plugs. 

I actually cannot believe the engine has withstood the knocking.  It would have killed an ordinary engine.  I have kind or ruled out the higher operating temperature as being a problem.  It really  is not running much warmer than in the north, the cooling fans so come on when the guage reaches the first mark past half way.  The needle never goes anywhere near the red and there is not any  loss of coolant. 

I am at a higher altitude. 

If  the knock sensor does the trick, I will let you know.

Thanks again,
What a knowledgeable group!
Jon

1st - do look at the timing as brougham1 stated .. i believe more knocking is caused by timing issues
than anything else. 

2nd  would be the posibility of carbon deposits.  read the WOT as per this website. 
not everyone's definition of the WOT  makes for a proper WOT.