3400 knock/ping issues

[rsisbetter]

for a while now i've been having some knock/piston rattle. and i've tried some solutions with no results yet. my ks circuitry is right on, (volt reference, and sensor resistance), so there is no problem there. I have not thrown any codes either. I've checked the fuel pressure, it rides at 45psi idle. BTW: this is an 03 3400 from an impala, with about 17k miles. I've tried switching a gas station once, but still did it some, (but i should try a different station yet again) The condition started, as when i would be in 4th or 5th gear at low rpm, and hit the throttle suddenly, or even somwhat slowly, and would have affirmative piston rattle. it will usually NOT give me any fuss if i slowly push the throttle down to WOT. I have mild mods, intake exhaust, udp, tuned chip by a v6z24 member, (using multech 2 injectors also). TODAY, it was really bad, i was hearing some knock in 3rd acceleration, and 2nd gear WOT, above 4k rpm, ? at this point i dont know of what else there is for me to try. (tomorrow i will pick up a different ks, and one from a 3.4 iron head, and try those). Otherwise i'm looking for suggestions, as im not sure what to do, besides 1. different gas station 2. colder plugs? 3. possibility of carbon build up? One time there was no knock, was when i added 3 gal of 91 oct, and some lucas octane boost, and at that time there was no piston rattle. I also asked about using a AFPR, to allow more fuel in during the pulse width, but i was told that was not a problem... Any suggestions appretiated much.

thanks
cody

[rsisbetter]

anybody have any suggestions?

thanks
cody

[ForcedFirebird]

A KS won't change the fact that the car is knocking. A fouled plug would decrease detonation. I would start by putting your stock chip back in and see if the problem still exists.

[rsisbetter]

A KS won't change the fact that the car is knocking. A fouled plug would decrease detonation. I would start by putting your stock chip back in and see if the problem still exists.

im using the m2 injectors, so if i go back to the stock prom it would run excessively rich, ( in turn probably knock less). I could try new plugs, but the stock delco iridium's or whatever they use from the factory, are about $6 apiece... the biggest thing i've done so far, is using octane boost, which eliminated the knock, so maybe the problem is just finding a gas station worth a shit...?

cody

[3400-95-Modified]

Need to adjust possibly AE tables, and some of your PE settings...

I'm not sure on what your ECM setup is so I don't know how you edited your chip to begin with... It sounds like your OBDI but I'm not sure.

If those injectors are 00+ injectors they NEED to be run at 55PSI at WOT to flow what they are rated at, If you run them at 45, they are no better than a stock set of 95 3100 injectors, 17lb/hr IIRC.

[rsisbetter]

Need to adjust possibly AE tables, and some of your PE settings...

I'm not sure on what your ECM setup is so I don't know how you edited your chip to begin with... It sounds like your OBDI but I'm not sure.

If those injectors are 00+ injectors they NEED to be run at 55PSI at WOT to flow what they are rated at, If you run them at 45, they are no better than a stock set of 95 3100 injectors, 17lb/hr IIRC.

I had a v6z24 member tune my chip for me, he tuned it for m2 injectors, possibly slightly higher VE, and said the spark table is unchanged. i'am running obd 1. the engine is a 03, and im using the m2 injectors, and fpr that came on the engine. (stock j fuel pump). at idle, im running 45psi fuel press. and if i hit the throttle just a tad, it jumps up over 50. but i dont have a way of telling what the WOT pressure is while driving. ( i need to get a fuel press. gague). Hopefully i'll be getting in on the ostrich 2.0 gp, so i can play with some of these parameters that are suggested to me.

thanks
cody

[3400-95-Modified]

Pull the vac line going to the pressure regulator, that simulates a WOT condition... kind of... It simulates what pressure you should have, but it could be lower if your pump can't keep up when the injectors are at a higher PW.

[rsisbetter]

Pull the vac line going to the pressure regulator, that simulates a WOT condition... kind of... It simulates what pressure you should have, but it could be lower if your pump can't keep up when the injectors are at a higher PW.

great idea! i never thought about that, i'll try it and give you some results.

thanks
cody