my2kTA

iTrader: (7)

I need some help isolating why my car is pinging. Its not a real rough ping, infact I didnt even know I had the problem until i was on the dyno this weekend and could faintly hear it.

The car is completely stock except for the fact that it has a flowmaster exhaust from the previous owner. I took out the baffles recently but that wouldnt affect the dyno.

Also, I was able to get someone with a scanmaster to show me the readout of the knocking. When driving normally it hit up to 8 degrees. When i stopped and put the car in 3rd and floored it, it only got up to 3 degrees.

I only run 91 octane gas from either chevron, texaco, 76 or mobile. I was hoping i could of gotten bad gas from a chevron in a lower end of town.

Ive never had to deal with detonation before so im not to sure of any other symptoms. It kind of feels as if the car is hesitating when shifting from 3rd but other than that it could be me. I was told it could be the spark plugs so I will probably end up changing them within the next week or so. I dont think they have been done since the car was bought - 48,000 mi ago.

I would like to start out with the most simple things first, and then work my way up from there. Where should i start?

On my dyno graph, i wasnt able to see much of the knock as i thought.

jimmyblue

iTrader: (11)

Crusty plugs can be a source of preignition.
Long term oil consumption (PCV) is a good
source of said crust (not just the plugs,
generally what you see on the plug when
you pull it, is all over the rest of the
combustion chamber). Change the plugs, if
you see a lot of carbon then you might want
the top end cleaned.

You don't see knock or knock retard on the
dyno, per se. You may see its symptoms in a
lower HP/TQ overall, or, if it comes in
abruptly, an unusual dip in the curve. The
dyno curves you got sure look odd, there's
a cliff well before you should hit rev limit,
and the curve goes backward. Even if you had
knock retard, it should be a few tens of HP,
not a total cutout and foldback of the RPM.

However, sustained high output is going to heat
you up, and maybe grossly exacerbate the knock
problem (especially if you have chamber wall
preignition). And preignition has a way of
increasing glow points & chamber temps, making
a self-sustaining problem sometimes.

Start by reading the tea leaves (plugs).

my2kTA

iTrader: (7)

i think the reasons behind the curve is because the guys that were running the dyno were afraid to push the car to redline with it pinging...even when i told them that i wanted them to just to see the max output.

robertbartsch

Change plugs, buy premium gas and install a colder therm


You can make your stock therm run colder by disassembling it and installing a shim in the housing where the spring pin sits ...I used tin foil for my simm....it runs at 160 and no longer pings....

you can also use "seafoam" to remove deposits from the heads, pistons, valves etc. I never used it but have read it works....the engine smokes bad after seafoam for 1/2 hour or so, however...who knows what it does to cats???

my2kTA

iTrader: (7)

do you have any details on how to install the shim? where exactly it goes and how to keep it there?

I do run premium gas, the best out here is 91. I was also able to get a new tank of gas to see if it was bad gas that was causing me to ping. however, it still occurs, but only above 5000 rpm. in normal driving, i dont come anywhere near that mark. Also after pinging, the car smells of electicity, kind of like when something is starting to get hot or burning.

zTrackerz

Here is a link that contains info on changing the temp of your stock thermostat..... But keep in mind you also have to change the time the fans come on also.......... Right???

http://www.ls1info.com/article.php?sid=180