Zoegirl

OK.
Im having a modest amount of detonation at low speeds. Ive had our clubs computer man take some of the timing out.
It worked for a while & its back again. I cant keep on having computer man take timing out, Im gonna lose more power. I cannot afford to have a full dyno tune right now.
Should I fill it up with 100 octane? ($6.00 a gallon)
Or should I just get an octane booster?
I use good gas usually 91 octane from Shell. I also take very good care of my car. Im also having a new fuel filter shipped to my house, its been driven about 10,000 miles since the last time I had it replaced.
As far as this goes, what do you think?

Sneakyws6

Try resetting the ECM. When I moved a couple of years ago my car was detonating under light loads for some reason. I reset the ECM and then went out and did a drive cycle and it never came back.

Turn the ign on but do not start the car.
Go under hood and open both of the fuse blocks.
Pull the PCM BAT and PCM IGN fuse. Leave the fuses out for a couple of minutes.
Turn ign off then replace the fuses.
Turn ign on and start car. It may or prob will stumble at first. You can kill the car and the turn the ign on and restart it again and it should start just fine. Now go out and drive it for a little bit so the ECM can start the relearn process.

brad8266

iTrader: (23)

What are your mods? Also can you hear the detonation? What does it sound like? It could just be hesitation from needing a tuneup. Did you log knock retard in the PCM?

Exhaust can cause false knock to occur. I would first run some seafoam through the intake to clean the piston tops, and give the car a good tuneup if it hasnt had one lately (plugs, wires, fuel/air/filter, pcv valve). Throw some 100 octane in too to see if it goes away.

If all that does not do the trick you might want to use software to desensitize the knock sensors some.

My headers and x pipe cause false knock so i desensitized the sensors 10% and it stopped pulling timing.

Zoegirl

Brad my mods are:
SW LT headers
SW catted Y-pipe
Magnaflow catback
K&N filter
Also, the round filter behind the airbox is clean.
Sneaky, Im going to try that.
Ill get back to this thread.

brad8266

iTrader: (23)

Ok the exhaust can cause false knock, although if it was false you would not be able to hear the knock, you would just see knock retard on a scanner.

Ditch the K&N filter also and switch to a paper filter, the oil from the K&N can go through and get on the MAf wires which can screw up your fueling and can cause the symptoms you have. By the way that round filter that you are talking about is not a filter, it is a air straightening screen for the MAF sensor.

What you want to do is clean and lightly oil the air filter (or like i said just get rid of it and get a paper filter), and take the MAF out and clean it with electrical contact cleaner, then reinstall it all and see what happens.

When was the last time you changed the plugs/wires and fuel filter?

Zoegirl

OK Brad,
I just went through the steps myself with the PCM stuff.
I did notice alot more pickup, but as far as the detonation its a LITTLE better.
Im going to the auto shop right now and picking up a paper filter.
Now that I think about it seems like when I installed the k&n filter thats when all this started.
As far as the tune-up goes I just had my spark plugs replaced about 3 weeks ago.NGK I believe, Master of Disaster puts those in all our cars.
I just recieved my new fuel filter in the mail & its getting installed tommorow.
Im not sure about the wires because when I open the hood all I see is wires.
There are some long wires on the left of the engine that look brand new.
I will keep you posted.

blkbird

iTrader: (28)

This might sound dumb but, how can you tell you are getting detonation? What are the simptoms?

Screamin_Z

iTrader: (2)

u might also be hearing valvetrain noise thru the stainless steel headers, which can be mistaken for detonation. there should be no reason why ur getting detonation...u are running 91 right? have u switch gas stations (companies) or do u know if ur regular gas station has been gettig gas from somewhere new? Some of the boosted/ high compression guys around here started noticing detonation when QuickTrip switched gas carriers. They went to E10 at Kwik Shop and thier problems went away. Ur city should have E10 91 so find out where it is and call that computer guy to put back ur timing that he took out. U might also check into changing ur knock sensors.

Zoegirl

When I push down on the gas pedal it kind of sounds like a bunch of tiny marbles in a can.
Also, I know for a fact I have detonation because of my dyno results.
I also agree with Brad it might be false detonation. Thats what I think he is trying to explain.
I did install a paper filter. I have not driven the car enough since then to really tell the difference yet.
Whats funny when I took out my k&n filter it was DIRTY & I just cleaned it the beginning of Dec.

Zoegirl

Thanks 4 the input.
Im going to also check on the knock sensors.
If this problem gets fixed I will definitly have computer man program my timing back in.
Whatever saves me from having to get a full dyno tune. I cant afford that right now.
I am running 91. If I was rich Id be running 100 octane but at $6.00 a gallon I dont think so.

Screamin_Z

iTrader: (2)

detonation, u can hear ur engine making ticking, clicking or high pitched knocking noises. detonation is pre combustion before the actual combustion (before TDC and spark plug ignites). it's from carbon build up, bad gas/not enough octane...and others I cannot think of. what ignites is an area of the combustion chamber (piston, valve, something that has an edge to it and has got VERY hot and causes a "spark as the piston increases pressure on the up-stroke. Just like my friend in his 01 Lightning, he was running a 10lb pulley on 91 octane he melted 3 plugs.

Zoegirl

Thats exactly how I wanted to explain it.

brad8266

iTrader: (23)

Ok, if you can hear it then it surely isnt false knock. You need to run a can of seafoam through the engine forst to clean out the combustion chambers, the if you havent done it yet give the car a good tuneup. Take care of the air filter and clean the MAf too. Then go from there.

Zoegirl

Im actually looking forward to driving it tommorow to see the difference.
Thx 4 everyones input.