pinging problem

[kj31067]

i just developed a slight pinging at 1/2 to 3/4 and its real pronounced at a full 1-2. i suspect citgo 7-11 gas as that was the
last fill up. i had 3/4 of a tank and topped it off at shell which i usually fill up at. always put 93 in .. stopped at a sunoco because they used to sell 94. no more.... i will be taking it easy on big red hoping that another fill at shell will cure it. i have a question though.. i m pretty sure if i send my lidio prepped xcal back he can load a tune for 91 or 92 octane,but i was going through the end user options and i saw adjustments for spark over 3 seperate rpm ranges. would this be a quick fix? if i send xcal in for lower octane tune will i see a noticeable loss of power? any help ,thoughts or insight are welcome and appreciated...........keith:)

[KillJoy]

I have been told, that for a bad gas tune, to remove 5 fom Spark across the board.

KillJoy

[kj31067]

thanks man

[SergntMac]

Chicago gas sucks these days, seems it's Citgo's problem today, and that's what I buy. Just when we drop back almost a whole dollar per gallon, the gas itself gets really sub-standard in quality...Go figure?

I agree with your synopsis of poor fuel quality, but I cannot comment on your tuning questions other than to say that all tunes can be adjusted for lower octane fuel. I'll add a "yes", you should expect a decrease in overall performance, perhaps MPG as well. Before you jump at this retune option, drive it out?

Just for *****s and giggles, I'll add that just before my due date on a routine oil change, I add a pint of Seafoam to the crankcase, and a pint to the fuel tank, and fill-up. Just about the time I'm out of fuel, it's oil change time, and this program seems to help with the overall problem of sporadic low quality fuel.

Chicago has the worst fuel quality problem now, more today than I have ever seen...IMHO.

[MitchB]

Funny you should mention this as I just retuned my father's 03. I drove his car to my house to take care of some preventative maintenance issues and I datalogged his car during the drive. I saw the the EEC was pulling large amounts of spark at times via the knock sensor and this was during normal driving. Called him and discover he's been using 89 octane gas. Went through several rounds of adjusting and datalogging. Wound up pulling on average about 2-4 degrees of spark almost everywhere in the spark table. Also reduced the amount of spark that's added in with EGR as I have increased EGR at light loads for fuel mileage. I am pretty sure I had previously changed how the EEC uses the knock sensors in that I made adjustments to the spark pull and add-in rates so the system ends up being a little more sensitive for safety's sake.

The spark adjustment you have is a global modifier meaning it will add or subtract spark from your EEC's end calculation . For example, this means at idle as well as part throttle, WOT and coast down. As a safeguard, I would pull 3-4 degrees of spark and drive easy for now.

Mitch

[kj31067]

thanks guys . i think for now i will drive it out gingerly and if i still have a problem , will knock back spark via the tuner in those 3 rpm
ranges....i m thinking the pinging will go away with the gas as this is the first time i have had this problem and i havent changed anything
to the car to cause it..............

[kj31067]

well i changed my mind. slow at work so i went out in the parking lot and pulled 4 from each range.......took it for a short spin.....25 mile trip home will be the real test...convienent having tuner in trunk just in case i have to put it stock before flatbed arrives ,if the need ever arises..............