2002 gmc ann spark knock

[glenboy]

does any one have a problem with spark knock on a 305 gmc motor ??/ i have tried premium fuel,,injection cleaner and it will not go away can someone please hep me,,,it only pings when i accelerate at any speed.i am thinking egr but people say no????

 

[Lyman]

I had a 350 do that, it was carbon build up in the intake. Premium helped my problem.

 

[KevinD]

Have you checked the timing?

 

[glenboy]

changed EGR and BAM-O more hp less ping egr 165.00 o-reilys auto parts

 

[tmdry]

My 01 is doing the same, I mostly get a bit of rough idling when I'm at a stop either on Drive or Parked. Drives fine, I've gone thru 2 bottles of injector cleaner, fuel pump, and I also run premium fuel.

 

[dgardner]

There's a Technical Service bulletin out on these engines that a corroded rear spark-knock sensor can cause the pinging as well. Something to look into if you still have some ping.

 

[glenboy]

i think were on to something here thank fellas

 

[glenboy]

i also found that the PCV hose was collapsed and the pcv valve was full of gunk...once i changed these 2 items my van ran like a new van...the pcv hose was run over the top of my pto shaft .and that is why the hose collapsed from heat

 

[joeynbgky]

Do you have any codes in the computer? If your knock sensor was malfunctioning you would have that code......... So I am 100 percent sure you had a check engine light on... what did it say? I have a Gm Tech II scanner with software..... I can look it up for you

 

[tmdry]

I'm not sure if I'm having the same issue as him, but on my 01 GMC Savanna 5.7, I'm still having the low idling when the van comes to a stop, it's worse when it's super hot out(feels like it's going to turn off). I do have an engine light on, had that looked up and says 02 sensor, but was told the 02 sensor wouldn't caused that. Sometimes it does shut down while driving in traffic, major pain. Than it turns back on.

I've had the spark plugs changed 2 months ago, along w/ the fuel pump, cleaned injectors, new alternator, new plugs, I forgot what else at this point. My go to mechanic, told me to leave the van w/ him all day, but it's my only van right now.

 

[glenboy]

i also have a low idle

 

[Larry Cobb]

Glen;

I would check the spark timing with an ECM analyser.

On my 2005 GM PU, I can set the spark timing maps for any advance level I want at any throttle & load level.

A good tuner should be able to do the same for you.

Larry

 

[Mountain View Carpet Care]

Take it to a shop. You clean carpets for a living. Knock is very bad thing. I have a race car out in my garage that broke 4 pistons cause of knock. There are so many things that can cause it from lean miss fire to carbon build up, intake leaking,ETC......