Mechanics

95 SC2 ENGINE NOISE

1995 Saturn Other

I have a 95 Saturn 1.9 double overhead cam. When I rapidly hit the accelerator the engine has a spark knock sound, I was told it could be a stretched timing chain, I checked the compression on all 4 cylinders and the compression is fine, this tells me the chain hasn't jumped. Could the chain still be stretched to the point it's hitting the outer case, If it is stretched why hasn't it jumped, it runs to good to be out of time. I'm leaning more to a spark knock caused by a sensor. I replaced the MAP sensor with a new one, I also replaced the Electric (not vacum) EGR valve with a new one, and a new knock sensor, and a coolant temperture sensor, nothing helped. The engine also surges up and down. One more thing, I used a scanner on this vehicle and no trouble codes were found, but when I use the scaner to view data, I'm getting a Quad driver 2 bad, I was told this is in the computer, I tried a second hand computer and still get the same data, this tells me something else is giving me the bad quad driver reading.I also read that when this problem is corrected the quad driver should reset itself. Any suggestions would be deeply appreciated. Thanks
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Bob G
November 10, 2006.



Im repairing a friends 96 saturn and I can hear thr same problem. It I also slow at acceluration and the noise goes away at higher rpms but at idel it is horrible at an idel and has no spark on two cylenders coil packs have been test and are good. So same advise would be great

Tiny
J REDNECK
Jan 1, 2007.
I own a 92 Saturn so I don't know how much what I know will help, but for what it may be worth. The 92 has various systems to automatically retard and advance the spark based on engine load, air temperature, altitude, etc. From what one comment above mentioned, it sounds like the spark advance system may not be working. On the 92 there was a knock sensor whose job it is to change the spark timing if the engine starts to knock. The Haynes manual I have said I could check the sensor by rapping sharply on the engine block while the engine was running, and listen for a change. That is much more difficult than it sounds (difficult to get enough swing room, and also hear the changes), so I replaced the knock sensor. On the 92 it is mounted on the passenger compartment side of the engine, so I got to it from underneath the car. Again, I don't know if any of this relates to your vehicle, as there are a number of years between yours and mine.

Tiny
Skyranger243
Jan 2, 2007.