pinging after changing main relay

I had the infamous hot start issue.
Thanks to this forum, I replaced the main relay (purchased one from local dealer) and all has been well with the hot start problem.

However, ever since replacing it and resetting the ECU, the engine pings under full throttle.
No other work has been done to the motor after replacing it and prior to this I ran the timing @ 18 degrees advanced with Chevron Supreme (91 octane) without issues since it was new.

I retarded the timing between 14 and 16 degrees and it still pings under full throttle between 4500-6500rpm. I replaced the spark plugs with NGK v-power stock units (same units that I had) and no change either. I regularly change the fuel filter (which is only about 2 months old now) and have been using synthetic oil and Honda filters since the car was new. The fuel injectors seem sound with only minor, consistent ticking and the valves are properly adjusted, although a valve job is certainly in the near future since I have 160,000 miles now. I use Berryman’s B12 Chemtool in the fuel tank every 3000 miles and have been doing so since new without any adverse affects. And no, I am not throwing any DTC’s.

So, I placed the original main relay back into the car and it pings slightly less than with the new main relay, but still noticeable. And yes, I reset the ECU after replacing the relay and several other times just to get a baseline, but have not noticed any positive changes. It does ping more noticeably in hotter weather.

stock B18A1
Dinan ECU //and no, the manufacturer does not make units for Acura anymore
GReddy 285cc fuel injectors
STR Titanium fuel rail

Has anyone seen this behavior or know its cause? I am thinking that the ECU’s values have somehow changed now since it has been years since resetting it.

hey i live in Sacramento and i was calling all over for a MFR, where did you get yours? oh, this may be a stupid question but im new, how do you reset the ECU? thanks,

resetting ECU

with ignition off and a US spec car,
–remove the 7.5amp backup fuse in the underhood fuse box (passenger side shock tower area) for about 10 seconds and then re-insert it.

as for getting a main fuel relay, well any Acura dealer has them in stock as they are heavily used items, especially here where it is hot.
Get the dealer part. You may find that its bracket is upside down. This is OK; just flip it around to install it. I validated this with the service manager at Niello Acura here in town who also validated that the part number on the unit may not match the OE part found in the vehicle.

Good luck.

So, who can answer my question?
Do I perhaps have a bad (ignitor) ignition control module or perhaps a bad ignition coil? I sure wish I knew…Thanks folks!!

Well, I am beginning to think that it’s California’s SH*T fuel…I know about 4 weeks ago, the State switched to its Summer blend, which is typically a few points lower in octane than its Winter relative…
Doesn’t totally answer my question, but its a thought, I suppose…