Pre-Ignition

[Robert Dyck]

I have a problem with Pre-ignition in my 97 GTS...... even though I drive it hard.

I read where solutions involved additives to remove carbon build-up, as well as colder plugs.

Question: Do additives, which loosen carbon build-up really work. If so, how is it carried out. I've tried this and it is very temporary.

Will colder plugs ( I think NGK-7252's) were mentioned, really solve the problem?

While temporarily solving the problem, will colder plugs contribute to additional deposits??? By not burning as many fuel molecules as a hotter plug??

Is the ultimate solution ....... to have the heads removed and have the carbon ground off??

I'm getting really ********** with this pre-ignition problem. And I shift at over 3,000 rpm in every gear. I try to run hard....... but still have the problem.

Any thoughts would be appreciated.

 

[GTS Bruce]

How about a lower temp thermostat?Probably pick up a few Hp too.A 180 deg should be fine.Like getting a 1.5 point increase in gas octane. Bruce

 

[Ron Hickey]

About a month ago I posted a request for help with a similar problem with my 97 GTS. I got lots of great suggestions from people on this board. Most involved carbon deposit buildup. My Viper tech started out by blaming the problem on oxygenated fuel this time of year. Not buying that explanation, we ran a can of BG 44 thru it and then tried a can of STP fuel cleaner (silver can). No luck. Cleaned the throttle bodies, replaced the fuel filter, replaced stock wires with MSD's. No change. Took the car in to another Dodge dealer in our area (Washington DC) to let another Viper tech have a shot at the problem. He found that the Intake Manifold gasket was leaking. He replaced it and the problem is gone.

As you know, nearly all the 97's had flakey IM gaskets -- there is a TSB for replacement. The problem usually surfaces as a really high idle (1500 RPM). I never had the problem, but once I heard about the TSB I had the IM gasket replaced anyway. My dealer did it at no cost. This was back in Spring of 1998. So the car now is on its second replacement IM gasket. But so far at least, the pinging is gone.

Hope this helps...

 

[Robert Dyck]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ron Hickey:
About a month ago I posted a request for help with a similar problem with my 97 GTS. I got lots of great suggestions from people on this board. Most involved carbon deposit buildup. My Viper tech started out by blaming the problem on oxygenated fuel this time of year. Not buying that explanation, we ran a can of BG 44 thru it and then tried a can of STP fuel cleaner (silver can). No luck. Cleaned the throttle bodies, replaced the fuel filter, replaced stock wires with MSD's. No change. Took the car in to another Dodge dealer in our area (Washington DC) to let another Viper tech have a shot at the problem. He found that the Intake Manifold gasket was leaking. He replaced it and the problem is gone.

As you know, nearly all the 97's had flakey IM gaskets -- there is a TSB for replacement. The problem usually surfaces as a really high idle (1500 RPM). I never had the problem, but once I heard about the TSB I had the IM gasket replaced anyway. My dealer did it at no cost. This was back in Spring of 1998. So the car now is on its second replacement IM gasket. But so far at least, the pinging is gone.

Hope this helps...


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Ron: Thanks. I check the gaskets very closely. I don't hear anything though. BTW, the gaskets have been changed twice already. Wouldn't surpise me if they are leaking again.

 

[phiebert]

Does a leaky IM gasket also result in lurching? I have adjusted my throttle bodies to be just right (left leading, etc.) but still have a little bit of parking lot speed lurching. I don't have the high-idle, in fact mine is so low it almost feels like it's going to stall sometimes. I don't have any pinging that I can detect either so I don't have a lot of the same symptoms but I recall thinking I have heard someone say that leaky intake gaskets can cause lurching too.

 

[FRANK]

Gee guys...hasn't anyone even thought about putting a vacuum gauge on your motor? If you have an intake gasket leak you'll see a low vacuum condition. If you don't know what a vacuum gauge is, go to your local Sears and buy one. They are under $20. If you're really cheap and don't want to spend the money spray around the intake runners where they meet the head with some Gumout. Make sure to get down in there. If the idle goes up when you spray around a runner, you've just found the leak. A vacuum gauge also includes a detailed diagram as far as inches of vacuum and problems with the engine internals. Keep it simple and real fellas...

 

[Sean Roe]

Robert,
As hard as you run your car, even if you do have an intake leak causing the pre-ignition, I'd still put in some cooler plugs. Autolite # 3923 are a good choice (in my cars).

 

[FRANK]

Mention the vacuum gauge to the tech. If you have an intake leak it will read between 11-14 inches of vacuum. A normal motor should be pulling at least 18 inches. A finely tuned motor should pull 20-21...

 

[Jerry Scott[CO]]

I had the same pre-ignition problem after installing try-y headers. I am using the NGK plug: FR5-1 (NAPA 7252) and no longer have the problem. This plug is just slightly colder and does seem to fix the problem.

When you are changing the plugs, if you can find access to a borescope, stick it inside the plug hole and look at the head to see if you have any carbon build-up.

 

[Robert Dyck]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Sean Roe:
Robert,
As hard as you run your car, even if you do have an intake leak causing the pre-ignition, I'd still put in some cooler plugs. Autolite # 3923 are a good choice (in my cars).


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