New info for this thread...
I get the occasional engine comm error on cold start that always self clears. Not a real concern but it annoys me sometimes. Overtime my best guess has been related to voltage drop when the starter hits peak draw given the factory 4 awg wire and length of run (spoiler alert it is NOT even 4 awg). I decided to rewire over the off season with 0 awg and ordered everything I would need.
Today I got started by epoxying some marine ply being the carpet in the battery compartment to mount some 3/8 lug bus bars on. While that was clamped and curing I focused on the engine compartmnet and added some 3/8 connection studs to the back wall. Then I turned to the start solenoids and mades some 0 awg connections to the positive stud. When I decided to just loop off the ground wire that goes from the batteries to the starter is when things got interesting.
As I prepped the factory starter ground wire for a new 4 agw selterm lug (to the new engine bay terminal I am running 0 awg to). I knew right off the wire was small. I proceeded anyway and when the 16 ton hydraulic crimper bottomed out the lug slid right off the wire. I decide to size down to the next dieset. That worked. But now I had to figure this out. Sure enough the factory wire from the batteries is 4.92 mm in diameter (average of 6 non-compression measurements at two different locations). Well under the minimum for 4awg but also not labeled as 4 awg either.
Given how power gets to the ECU fuse panels and then the ECUs it is certainly possible voltage drop at engine start is causing a myriad of canbus electrical woes. Particularly when not running a SLA start battery as those have a higher float voltage to start with. The 0 awg run will hopefully improve things and I will report back.
In the photo below the black wire is the factory stuff (good tinned copper wire just too small). The small red wire is knuknoceptz Kolossus Fleks 4 awg and the larger is 0 awg (both are well above spec for their rated size. The selterm lug terminal is just above 4 awg spec to fit on 4 awg wire. Almost seems as if I could fit two of the factory in one but struggle to fit Knuknoceptz.
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