I just got a mail order tune. When I put the ECM back into the car and drove it under WOT the car starts to ping. Almost like you have a bad tank of gas. I used three different brands of gas all 93 octane. The tune was for premium fuel 91 or higher. The car is stock except for a set of headers and cat back. The motor is a jasper rebuilt with about 10K miles. At that time the opti spark was replaced with a new Accel unit and the plugs and wires were included in the jasper install kit so I have no idea the brand it was installed by a certified shop. I brought it to the mechanic he suggested a fuel octane booster first so I put some STP octane booster in the car and drove it like 10 miles no difference. The mechanic wants to replace the wires, plugs and opti spark. Fuel system checks out fine. I'm assuming its pulling too much timing. I'm thinking about changing out the wires using a over the valve cover routing in case they are burning to see if that works. Do you think maybe someone who does dyno tunes could pull some timing out to fix it? I'm assuming there's not a problem with the mail order tune and that is just discovered a problem that was about to happen. Any ideas?

 

I was just outside running the car it appears there's an exhaust leak on the driver's side. Sounds like its coming from the 3 bolt flange on the header under the car. Could this be causing the engine ping? Not sure if this leak is causing the air/fuel ratio in the computer to cause the pinging problems.

 

very likely could be..

 

Sometimes, an exhaust leak sounds like a "ping". Unless you put a scanner on it, and looked for knock retard, you have not idea if it was an actual ping or the leak. Fix the leak, and see if it still makes the noise.

Unless the tune eliminated the knock sensor, or severely limited the maximum amount of timing retard the PCM could use, to eliminate knock, there is no reason you should ever hear knock. The PCM can pull 15 degrees of timing, in stock form. The knock sensor picks it up before you can hear it.

 

The mechanic said no codes were showing. There are no lights on in the car. I did replace a 02 sensor about 500-600 miles ago and reset the PCM and the engine light went off. It also went through NJ inspection right after that so there must have been no codes showing. I'll get the exhaust leak fixed and see if the noise goes away.

 

i like the copper gaskets they can be re tightened most of the time. header bolts are always coming loose unless you get locking ones and use thread locker on the collector

 

It sounds like its coming from the 3 bolt flange collector on the bottom of the header under the car. Pacesetter gives you these flimsy paper gaskets. The passenger side blew out in about a week. so i'm assuming the driver side finally went. I should have replaced both the first time. The exhaust shop that installed the headers didn't point out that the gaskets weren't that great. I should have looked at them before the install. I'm hoping this will fix the problem.

How about the actual knock sensor? How do you know when these need to be replaced? Everything went haywire after the mail order tune.

 

There is a code for the knock sensor, if the sensor or the wire is faulty.