Am I crazy or has this happen to anyone else? Engine question..

[Qualitywires.com]

I installed new plugs on my car and with my Jeff Morey Heads which is 8.9 to 1 compression...the car sounded deep and throaty. I have driven the car for about maybe 300-400 miles and now the sounds of the car is more muffled than before. Do you think it has to do with my spark plugs or something? I know I am not going crazy, but the car does sound more quieter than before I put the 400 miles on it. Any idea's? I don't think humdity or heat would cause this?

Any info would be appreciated on what the cause is, All I can think of is maybe it's the plugs? Not sure.

Thanks

 

[onerareviper]

Did you just fill up with fuel? I've heard people say with a full tank of gas if absorbs some sound. I never really noticed, though...

 

[2002_Viper_GTS_ACR]

Computer is learning/programming the new trim values, for your set up. If you want that sound again, unplug the computer for couple of minutes and verify. I bet it comes back, but as soon as you put the miles on the car, the comp learns again, and it becomes more calm.

Anway, dont call me asking me this stupid question either, NO I did not notice it on my car.

Jon.

 

[Jack B]

There is too much explained away by the PCM "learning". Learning is in closed loop and has nothing to do with open loop. You may pick up a few hp in mid range partial throttle, however, in WOT the engine is running on a fixed program. The only changes under WOT will come from fuel/ignition modifications due to temperature and altitude changes.

A more likely scenario is a bad injector or plug. Hook up a scan tool and check the rpm at idle. It should be 670-710. You can then pull plug wires and see if there is a change. When you do not find a change (after pulling a plug wire) you have found the faulty cylinder. I had an intermittent injector problem and there was a noticeable flat sound when it wasn't firing. You can also use a temperature probe on the header next to each exhaust port. On my Balenger's they run at 550-625 at idle. A cylinder not firing correctly will show a difference of 100-200 degrees.

 

[1TONY1]

I don't have a clue about your other question....but YES, you are crazy

 

[Qualitywires.com]

Jack,

If I had a bad plug, I think I would notice it while driving wouldn't I? I know I have on other cars.

I have a wideband on my car, but I don't think that is going to tell me if I have a weak injector which I don't think I do..hopefully.