So I’ll share my drama from my last couple of months . Engine just wasn’t running right and I swore I had a miss, but engine acted like it had a hunting idle.
I knew my MAP sensor was questionable since I got it from the JY. I decided to buy a genuine new GM from Rock auto. Received it and checked it before install and it was bad out of the box. Sent it back and got another, this one has been working correctly. My Map Daddy that is on my board is bad also. I think it ruined from gunk running down the vacuum line. Current MAP sensor is installed above the intake!
Engine still ran like poop, and I knew it had a misfire for some reason. Bought one of those HEI spark testers to test the coils . Found a coil that wouldn’t jump the spark - BINGO- I thought. Bought some used ones to replace my used ones and it still wasn’t right. Examined my GM plug wires with less than 10k miles and they didn’t look that great . Had a couple of extra wires and swapped some out. Ran slightly better but didn’t trust them.
Because if the bad weather , most of my troubleshooting was idling in the garage. When I finally got out on the road the car sputtered up any hill at low rpm. WOT she still got it , but any low rpm loading caused major issues.
All this time I was checking everything else on the engine; timing , tune , software updates , wiring , I just had re- wired the whole fuse box.
Did a lot of reading and read how easy these logic coils will fire off. Little over 2 volts across the logic side and boom.
I broke down and ordered MSD wires and new plugs. FIXED!
Have to keep all the spark in the boots or these d585 will fire off. Pretty scary if you are running a turbo ( Gollum -are you reading ?)
Hopefully the drama is over .Time to get my cam sensor working .
Side note: Timing light is NOT an effective tool to troubleshoot spark with wasted spark and d-585 coils. The flash is erratic . I saw wasted spark flashes on 3 of the cylinders and half that speed on the other cylinders