So, I've recently relocated to the Phoenix area and with that came hotter denser air than Tucson. Summer's rolling in and my car started to ping between 2-3K at moderate loads (under PE, but more than about 33% TPS: I'm guessing here as I didn't have a laptop to data log or adjust the tune). The coolant temps were rising with ambient temps.

At anything over 85°F the coolant temps at highway cruise (1500ish rpms) would maintain about 185°F (1/4 mark on the dash gauge), and in stop and go would climb to about 230°F. As the coolant temps climbed over the middle mark (210°F) the pinging would start, then keep getting worse (only between 2-3K rpms). All of this was with the AC on full blast. If I turned the AC off the temps would drop and no more issues. At idle the coolant temps exceeded the 3/4 mark, so heater on (at 100°F out) AC off and the temps dropped, at idle, to about 185°F again. So obviously the heat from the condenser wasn't helping the situation. But it's hot, and it's my DD so AC is a necessity.

I got lucky and a friend at work had an old laptop that wasn't working, so I fixed in exchange to borrow it to tune the car.

Long story short, I adjusted the coolant/spark correction table and it stopped pinging but ran like absolute crap under 2K rpms. Over 2K was great, smooth, good power and all that jazz; most importantly no pinging! But under 2k, my cruising rpms, it would buck and protest like I was killing it. Plus my coolant temps were hovering at about 210°F at highway speeds with 110°F ambient temps.

A little more history on the process. Before I adjusted the spark/coolant correction table I pulled timing from the main spark table because TunerPro RT wouldn't let me put a negative number into the charts (how do I do this?!). Then I found out that TunerCats will let me, so I adjusted the spark/coolant tables there without putting the advance back in the main tables because I was still getting a little pinging. This ended up pulling over 6° of timing below 2K rpms, but stopped the pinging.

So, I readjusted the spark timing curve below 2K rpms back to the original setting and all is good again. But, my main spark table looks weird.

Any takers want to chime in on why my engine would want a spark table that looks like this??

It doesn't seem right, but runs smooth and strong. At 95°F ambient cruising at 1500rpms at about 70mph my coolant temps stayed right at 175° on the dash (no data log, the program crashed before I could save it, Windows Vista). So it's running cooler and smoother, so it likes the table (I think). I'll know for sure tomorrow afternoon as temps should be in the 110+°F range. Hopefully it'll run cooler and get no pinging!

I also finally went back to MAF mode too. Still calibrating the tables for that, but they are very close to stock anyway (less than a 3% change so far).

 

I don't think that's odd.
That's a lot of cam for a 355. Your VE is so low below that 2000-2400 rpm range, that it wants extra timing to compensate for the lower cylinder pressure. At that 2000-2400 range the cam starts to "come on", filling the cylinders much better, so it wants less timing.

 

when you did the timing vs temp, did you adjust it at the KPA where it was pinging or all across the board? also the timing vs rpm vs kpa and you could go into the timing vs map, adjust all of these areas so that it only pulls timing not only when the temp is high but at that specific map / rpm area.

 

Funny... My car does almost the exact same thing as the op's car.. With 85*-95* temps I peg the temp needle to about 220*-225* with A/C on.. With A/C off its about 185*-190*

 

This makes me feel better about the spark curve. I'm going to add in a little more timing under 2K still, it's still a little rough there, but much better. Temps cruising at 70 were 210 with ambient temps at 114 and AC at full blast. Stop and go it got up to 230 still. I don't think there is much I can do about that with the condenser pushing 300°F right in front of the radiator. But, no pinging so I'm feeling alright with it if I can get it to drive smooth again.

I don't see any tables where I can pull timing based on rpm vs map vs coolant temps. I did adjust the coolant temp vs map according to map so more map has more timing pulled as temps increase. I only see 2 tables for this, spark vs rpm vs map and spark vs coolant temp vs map.

Only so much cooling can happen at those ambient temps, the condenser is getting to about 300°F in that case.




This last drive I had no pinging still, pulling about 3° timing at 220 and 6° at 240 in the spark vs coolant temp vs map table. Add in the 3° I pulled from the main spark table and I'm pulling 9° timing. I'll add in about 1.5° timing below 2K and see how that works for drivability and coolant temps.

 

Turned out I had an arcing spark plug on the #1 cylinder causing the low RPM issues. Funny thing, I was trying to tune it out and it did get much better. Idles better and drives better than before too with the new spark plug. 6th gear at 45mph with my cam on a 355 with no lugging or cam surge is an accomplishment me thinks, smooth as glass.

Some other issues I noticed that were caused by the crack porcelain/ceramic spark plug:
My voltage (data log and dash) only showed 12.2-12.4V at idle (I wonder if this effected my cooling fans CFM capability?)
My coolant temps at 90°F dropped about 15°F at highway speeds after replacing that bad plug too.


Thanks for all the input guys!