Spark knock

[Recon561]

I have a 95 ls and at lower rpm's with the motor lugging it spark knocks. But at higher rpm when it is not lugging no spark knock. Checked timing, retarded the distributor. Changed fuel filter, have air/fuel gauge and its not running lean Some one help going crazy

[FAHHQUE700]

air to fuel guage is just a light show... worthless... wideband = different story check for vacuum leaks, spark plugs, etc.

[koukis14]

air to fuel guage is just a light show... worthless... wideband = different story check for vacuum leaks, spark plugs, etc.

HAHAHA +1 for a/f guage comment. 99% of the kids that have them in cars don't know what the little "stoich" in the middle means anyway.

[AnthonyF]

^^^ lol. im buying a wideband as we speak. lol. w/b=FTW

[twinj]

I know that shit is annoying.

What kind of fuel is in there?
95 LS. Do you have a Knock sensor?
You might have to go and get the timming done professionaly.

My car use to do that then I started putting nothing but BP & Chevron 93 in there, and put my obd2 computer back in.

[Recon561]

Thanks for bashing my air fuel gauge I just like lights. All i run in the car is 93 octane. I have taking it too a couple places too get them check the timing and they say that it is dead on. As long as i dont lug the motor it runs fine. When i lug it just babying it thats when it spark knocks

[twinj]

Is it dead on with the timming gun(ignition), or with the pulleys lined up. Which one you talking about.

[QX56tech]

What kind of spark plugs are in it. Should be NGK

[Recon561]

Is it dead on with the timming gun(ignition), or with the pulleys lined up. Which one you talking about.

I made sure the pullys all lined up . Then took it too a buddys shop and had him check it with a timming light and it was good

[Recon561]

What kind of spark plugs are in it. Should be NGK

I am running the iridiumn plugs or how every it's spelled

[scttydb411]

is it a stock or chipped ecu?
93 oct
check/re-check timing
use stock ngk plugs and 1 step colder if you need to

when you say luging be more specific...(what load, gear, and rpm)

[Recon561]

is it a stock or chipped ecu?
93 oct
check/re-check timing
use stock ngk plugs and 1 step colder if you need to

when you say luging be more specific...(what load, gear, and rpm)

Yea all i ever run is chevron 93. And when i say lugging is when im in 4th gear around town at like 3k rpm and going to pull a slight hill it starts to ping. Or any time it is down around 3k rpm and I ease into the throttle to start to accelerate it will ping. The plugs that I have recently put in the car are NGK iridium plugs and brand new MSD plug wires also.

[AnthonyF]

Thanks for bashing my air fuel gauge I just like lights. All i run in the car is 93 octane. I have taking it too a couple places too get them check the timing and they say that it is dead on. As long as i dont lug the motor it runs fine. When i lug it just babying it thats when it spark knocks

no1 is bashing ur a/f gauge. we are suggesting getting a wideband b/c the narrow band is basically pointless. It doesn't tell u shit.

[blackshine007]

I lot of people misunderstand the grades of fuel some engines should be running on. Alot of engines run and make good power on just regular unleaded. Since you have a regular LS, non VTEC, you need to consider running on 89, or even on 87, and then recheck the timing. High octane is mainly used for cars that have either high compression or a high swirl combustion chamber, and the higher octane fuel has a slower burn rate. I would recommend dropping a few octane points. Your spark knock might go away.

BTW, what have you done to the internals? If you haven't done anything, go back to regular or mid grade. Just avoid premium until you increase the compression or boost it. It's basicly pointless in your car

[AnthonyF]

^^^ i agree. a lot of people put the 93 or 101 race fuel in the car thinking it makes there car go faster. It does not. If you have the car tuned with the 93 or race fuel and the timing is advanced or retarded then you will see performance gains...other than that, there is no need to run 93octane

[scttydb411]

when you get knock you need to increase your octane fellas. what you're saying regarding using 93 being unecessary is usually true, but i would highly doubt his knock will go away with using a fuel that tends to have a faster/less controllable burn. normally on an ls i would recommend using 87 or 89, but 93 has less resistance to knock. if you're knocking you're either too lean or too far advanced or way retarded with timing.

i would ditch the iridium plugs and go with standard ngk or ngk v-power. if you still knock on the stock recommended plug then go a heat range colder.

[Recon561]

Problem fixed Its running jam up

[green91]

What was it? even with timing fully advanced you shouldnt be having spark knock issues on a stock compression LS with 93 octane

[scttydb411]

if you post something like this you must explain when it's fixed...common courtesy.

[QX56tech]

What was the fix?

[Recon561]

The problem was the cams were out of time by like one tooth and I didn't realize it. I went back and redid the timing belt and realigned the cams and wow problem fixed. Thanks for your input guys.

[AnthonyF]

The problem was the cams were out of time by like one tooth and I didn't realize it. I went back and redid the timing belt and realigned the cams and wow problem fixed. Thanks for your input guys.

your very lucky. hopefully u didn't do any damage to the valves.