knock under tourqe

[stant093]

So i finally finished tinkering with my 94 SS and started driving it today. Well after letting it warm up from sitting for awhile, i take off down the road. When the turbo starts to spool up and the engine is making torque, it knocks, almost like a dirt bike with a broken piece of spark plug in the cylinder (had this happen a time or two when i was a kid and road dirt bikes, not a good sound!)

The sound goes away when just coasting and light gas, but when you stomp on it its a terrible high pitch, not consistant knock.....i replaced the plugs today and wires too....Tomorrow morning ill bring it to the shop and tear into it, but i was wondering if anyone might have some info tonight or something....


Thanks!

[BAC5.2]

First. The engine isn't using torque. The engine MAKES torque through the combustion process.

I bet the pinging is from an exhaust leak.

If it was knocking, that's what you have a knock sensor for.

[stant093]

i do apologise, the way i worded it was incorrect, but the point was understood...


Theres no exhaust leak, this exhaust has been replaced from the turbo back, in excellent shape, we already ruled that out last night over a big meal...


We changed the knock sensor and its still doing it. It seems to now only do it at about 5500 RPM, which is better than when we first noticed the problem (2500 RPM). Everyone i know seems to think its spark knock, tomorrow is another day, most likley were going to change the timing belt while were at it.....

[BAC5.2]

Is the ECU pulling timing?

[wiscon_mark]

what kind of fuel? Turbos are supposed to have premium....(not calling you dumb, but some members have used 87 ocatane on their SS's) :shrug: Could explain pinging/knocking etc.

Try thicker oil and/or Lucas oil additives and see if it clears up. Obviously parts are moving more/harder when you're accelerating, so maybe its a problem that's beginning, and it may get worse to the point that you hear it all the time....

Edited Typo @ 9:42

[BAC5.2]

When you are accelerating, no more parts are moving than when you are cruising. or idling (other than transmission related, or throttle body related). Things are put under more stress when accelerating, but no MORE parts move.

I'm still curious if the ECU is pulling timing or not.

[wiscon_mark]

oops, typo, I meant parts are moving MORE, not more parts are moving