turbo? Knock sensor? running lean?

[new288sup]

Originally Posted by IHateHacks

I'm telling you, you are running too much boost.

You can rule out 80% of what this "shop" told you.

You can check the resistance of the fuel injectors, 1.8-3.4 ohms for turbo models, but I already have the feeling you need bigger ones, and a bigger fuel pump running that much boost.

You should have replaced the fuel filter before you even started driving this vehicle so if you haven't yet, do it.

Accordian hose? Take it off and check for cracks. Better yet, check ALL vacuum hoses for cracks, i.e. ISC hose, PCV hoses, etc.

Like the fuel filter you should have set base ignition timing before you registered this vehicle.

You can test the O2 sensor voltage feedback. Connect a voltmeter to terminals Vf and E1 of the check connector. Voltage should fluctuate 8 times every 10 seconds.

And the cat, well you will have to take it off and look at it to see if its melted.

Or you can turn down the boost and see if thats the problem.

"did that slow down thing"- yeah thats the ecu retarding the timing, like I told you before.

Alright, Knock sensors Detect ANY knock, Rod, crank, or cylinder (pre ignition/detonation) running to lean (not enough fuel) causes Detonation which is basicly the fuel igniting before it is supposed to Because the piston/cylinder walls are TOO hot. Pre ignition is similar but it is normally caused by carbon/deposits on the intake valves getting hot and falling into the combustion chambers and could also cause (if hot enough) the intake valves to ignight the fuel on the way in.....RICHER IS better on boosted engines. anything more then 12ish pounds on stock fuel system is asking for trouble. In my humble opion replace your fuel pump, and regulator first.
the more pressure/flow you can give your injectors, the less the injectors have to work for the same amount of fuel....
Also Look up "top tier" fuels in your area, and try to stick with them.

If you are still having issues, then its not your fuel. ITs an engine knock.
Could mean 2 things, Wear on your bearings from too much boost and not enough oil pressure, or just not enough oil pressure for the boost you are running (pumps create FLOW NOT PRESSURE) (resistance to flow creates Pressure).....there is a thread im still looking for on here that mentions replacing the pump spring in the factory oil pump with one from a SB chevy, im still looking for the exact details.

Now keep in mind i am build a 600HP 7m, Using MsEfi, and a few other tricks... no, its not done yet, but if the math works out, i can make it 600 and a daily driver
Nick

[jrok]

check for short to ground in the knock sensor wire