Detonaton Issues??

[Mustang30212]

First post...here goes!!

I just bought a LL Green 05 GT with 25k miles on it. During the 5+ hour drive home from the car lot...I thought I could hear a little bit of detonation just as I cracked the throttle open.

I just figured the car lot used crappy gas and I'd fix that with a nice fresh tank of 93 octane. That didn't seem to change it and forum members from another site said that octane didn't make much difference and that some valve clatter was normal. Next fill up I put 87 octane in and now it pings like crazy. It's not valve "clatter" as they suggested..it's detonation!!

Any ideas?

I thought that for such low mileage and from sitting on the lot for 3+ months that maybe there is a bunch of carbon build-up on the pistons causing hot spots and hence the detonation.

Again...any input?

RH

 

[jroc07gt]

does the car have any mods done by previous owner? maybe the car has a tune on it and he/she didnt tell you.

 

[MrClean]

1st: Use only Chevron gas with Techron.
2nd: Add a bottle of straight Techron, then after two tank fulls, run another bottle of techron through it again.
This will get rid of deposits in your combustion chamber and valves with lead to insufficient heat transfer and therefore detonation (pre0ignition).

I just had the honor of meeting the guy at Chevron whose name appears on the patent for Techron. This stuff is light years ahead of the Shell and Exxon additives (that nitrogen crap that Shell is selling is hype...Chevron gas has has nitrogen as part of it's proprietary blend for 20+ years)

All OEM that are embracing direct injection engines are recommending techron because of it's superior performance in keeping the high pressure piezo-electric injectors clean.

 

[Kraftsman]

Car is probably tuned wrong. I'd bet the timing is advanced to far.

 

[Mustang30212]

The car is bone stock...never been tuned. Are you saying that it may have been tuned wrong from the factory?

RH

 

[Mustang30212]

1st: Use only Chevron gas with Techron.
2nd: Add a bottle of straight Techron, then after two tank fulls, run another bottle of techron through it again.
This will get rid of deposits in your combustion chamber and valves with lead to insufficient heat transfer and therefore detonation (pre0ignition).

I just had the honor of meeting the guy at Chevron whose name appears on the patent for Techron. This stuff is light years ahead of the Shell and Exxon additives (that nitrogen crap that Shell is selling is hype...Chevron gas has has nitrogen as part of it's proprietary blend for 20+ years)

All OEM that are embracing direct injection engines are recommending techron because of it's superior performance in keeping the high pressure piezo-electric injectors clean.

I usually try to only run Chevron. We have ONE here in town that does NOT add Ethanol..so I try to go there when possible.

Where do I buy a can of "Techron" from?

I was thinking of using SeaFoam...I've used it in the past with good success also.

RH

 

[Dex]

Could be the rattle from the plate where the trans is

 

[jroc07gt]

I usually try to only run Chevron. We have ONE here in town that does NOT add Ethanol..so I try to go there when possible.

Where do I buy a can of "Techron" from?

I was thinking of using SeaFoam...I've used it in the past with good success also.

RH

you can pick up a bottle from any walmart or auto parts store. make sure to buy the full system cleaner and not the proguard. the proguard isnt as strong imo.

 

[ski]

FWIW, a can of Seafoam dumped into the gas tank of my 05 GT got rid of a pinging problem. But it took 200 miles of driving to disappear.
If you car pings even with 93 octane, then it's probably caused by carbon build up. If treatments with Seafoam, Techron, etc., does not work, then changing the $park plug$ may fix it. If you change them yourself, then make sure you read the TSB on doing it.

 

[MrClean]

I've requested permission from Chevron to share specific information about Techron to illustrate it's superiority over the other additives. Stay tuned. For now, trust me, there's no problem with gasoline having ethanol in it, but you should really use Texaco or Chevron (same company, same additive) gasoline with Techron. When I bought my 07, I used nothing but Shell V-Premium, and at about 12000 miles I started to get pinging with my 93 tune. I switched to Chevron 93 with Techron (all texaco or Chevron gasoline has Techron) and the problem resolved itself within a few hundred miles because not only does it prevent deposits, it removes them to. Shell's additives prevent deposits on valves, but actually add deposits in the combustion chamber.

 

[Mustang30212]

Update:

SeaFoamed the engine today and went on a vigorous 45mile jaunt up the interstate in 4th gear at 80mph...cleaned her right out!!

I still have just a slight ping at throttle tip in...but I think that will clear itself up also.

RH