EXTINCT2000

Hello all, I have a 2000 Formula that has an audible metallic pinging sound at high RPM. I data logged it with a Diablo and it's showing 3 to 4 degrees of knock retard at full throttle. The tune is stock though, no Diablo tune. I recently replaced the fuel filter and ran fuel injection cleaner through the car. I've had a catch can on the PCV system since the car had 8k miles and it only has 20k now so I'd hope carbon buildup wouldn't be too terribly bad. What steps should I take to remedy this problem and in what order? I don't want to spend any more than necessary. Should I clean the MAF screen? Replace the fuel pump? Would plugs and wires do anything? What's the best way to narrow down what's causing your detonation? Thanks.

garygnu

get better gas ,maybe a colder plug.the knock sensors are doing their job.consider a frost mail order tune.cold air,cold fuel lessen knock.look at a cold air intake system.

SM105K

iTrader: (3)

OP mine does the same thing. I Seafoamed it twice (fuel system and engine). After Seafoaming it, I changed the plugs and wires (MSD, NGK TR55r's), put premium fuel in it, and I still get detonation. I think personally it is the heat with mine. I live in AZ, so it is hot right now. So I am going to put 5 gallons of 100 octane in it, and see if that clears it up. I need to take my car to NicD and just tell him to work his magic.

JD_AMG

What gas are you running? (should always be atleast 91) Are you guys sure its knock, and not an exhaust rattle? (02 sensors are known for rattling around, sounding metallic - search for this)
Why wouldn't the KR sensors pick it up and retard timing enough to eliminate it?

BobDoLe

iTrader: (11)

he did say the sensors were picking it up and pulling 3-4 degrees.

sounds like crap fuel. does it only do it when its hot? you could seafoam it - at least the part where you run it through the hose.

you also could pull off the maf, spray the wires with CRC Electrical Cleaner to clean them off - be careful with those wires as they are fragile and you could break one if you poked it with a qtip. that might help if they have stuff on them (like aftermarket air filter oil).

SM105K

iTrader: (3)

I forgot, I cleaned my MAF as well. I know it is detonation. I attribute the heat. When it cools down at night around 90ish or so, it only does it for a split second above 5600 rpm. During the day, it does it around 5000 rpm and is steady through the rest of the powerband. My 5.0 did it as well with the heat. I would just pull base timing out of the 5.0 during the summer.

TImmy_Jones

iTrader: (4)

Where do you live? What exhaust setup are you running? Sorry on my phone - if this info is in your sig.

Troy5061

iTrader: (19)

My car was doing this a while back. It was a combo of a bad fuel pump and a boogered up MAF. A previous owner descreened the MAF and it was making it run lean and spark knock from 5000rpm on up. My buddy has HP tuners and before I replaced the pump he could set the target afr to 9.0 and it would still run lean, like 16.0 lean. After I replaced the pump with the Racetronix he still had to set the target afr under wot to 10.5 to make it run 13.0. Once he disabled the MAF and switched it over to speed density it would run 13.0 just like commanded in the tune.

Sales2@Texas-speed

iTrader: (5)

I'd start with a gallon or two of unleaded racegas in there to see if it's picking up false knock, or true detonation/knock.

SM105K

iTrader: (3)

I went to the Dyno and NicD said I have a virgin PCM. We dyno'd it and the numbers were 293 HP and 307 TQ with an A/F of 14.1. Lean. We checked the fuel pressure on the next run, and it was fine. I went to the gas station, I tried to almost run it out of gas....and put 5 gallons of 100 octane Sunoco Unleaded Race Fuel in it. Still detonated. I bought my friends MAF off his 98 Vette, installed it, threw my K&N in the trash, got a fram air filter.........and now my detonation is GONE and it runs alot better esp in the higher RPM's. Going back to the Dyno on Wed to see what my AF is now, and see if it picked up any more power.

I went in order this order to figure out if it was the MAF. Seafoam, MSD Wires, NGK TR55 plugs, Dyno Pull, 100 octane Unleaded Race fuel, air filter, MAF. Runs like a top now.