techs, help!! pinging, spark knock

[mopower440]

I got a 1999 chevy silverado extended cab 4x4, has the small v-8, 4.8 liter. It wants to ping (detonate) when going wide open throttle. I have installed a new fuel pump, fuel filter, plugs and wires. We hooked up a tech2 at work and looked at the fuel trim with it running and the tech said they looked good. Then we drove it with tech2 hooked up, i nailed the throttle and he watched the tech2 and it did indeed retard the timing, so apparently the knock sensors are working.I did a carbon cleaning on it yesterday but it still pings at wide open throttle. It does a little better with premium gas but still get some pinging. Has no mods at all. Not setting codes either.

[skeet]

I got a 1999 chevy silverado extended cab 4x4, has the small v-8, 4.8 liter. It wants to ping (detonate) when going wide open throttle. I have installed a new fuel pump, fuel filter, plugs and wires. We hooked up a tech2 at work and looked at the fuel trim with it running and the tech said they looked good. Then we drove it with tech2 hooked up, i nailed the throttle and he watched the tech2 and it did indeed retard the timing, so apparently the knock sensors are working.I did a carbon cleaning on it yesterday but it still pings at wide open throttle. It does a little better with premium gas but still get some pinging. Has no mods at all. Not setting codes either.

Bad gas maybe?

no tune right? i know you said no mods but some leave out tuning

[mopower440]

nothing, all stock. no tuning, nothing.

[country_3030]

How many miles are on the motor?

[mopower440]

today at work we flashed the pcm to the latest program they have for it, still pinging...anyone have a clue? Thing runs awesome otherwise, uses no oil or anything.

[pl4yboy]

today at work we flashed the pcm to the latest program they have for it, still pinging...anyone have a clue? Thing runs awesome otherwise, uses no oil or anything.

You could start by answering questions asked.

[chvy=power]

Run higher octane fuel and see if it still does it. .. Also what is your injector duty cycle at wot?

[chvy=power]

Or try cleaning the maf. The iat is in te maf on the 99 iirc. The iat sensor may not be reading right and the PCM is not pulling the timing for higher intake air temps

[BigM]

.....Well I have the same problem with my 99 100% stock...When it starts pinging i put a few bottles of lucas high octane boost from autozone...and it always clears up....probably not the best solution but it works for a little while....

[mopower440]

not sure about the injector cycle, the techs at work stay slammed so will have to try to get them to check when they get a chance. all i know is when we drove it with the tch2, the tech said everything was normal. was wondering this, ok, it has 2 knock sensors, and the tech2 DID show it retarding the timing, but is it possible that only one knock sensor is working so its not asking for enough retard?