I have a 1995 K1500 that I did a motor swap on last fall. Also have factory 4L60E. I upgraded to a 383 but kept the swirlport heads and factory intake. I have developed a miss or hesitation while driving. Sometimes I can drive 15 minutes before it shows up. Sometimes it's there as soon as I start up (even cold). I have been working with Old School EFI on the tune and don't want to bother him with troubleshooting. He's been real patient working through the tuning process with me and I highly recommend using them for chip tunes. My extent of tuning so far is the ability to log data. I need someone more experienced than me to take a look at the logs and see if anything stands out. I can see a dip in RPM at the same time timing advance drops and injector duty cycle drops. I just can't tell which is the initiator.
Fuel pressure is gauged and is solid at 15 psi.
New ignition coil, plugs, ignition control module, distributor pick up coil. Injectors were new last fall. EGR is new, but deleted by tune. I've checked the TPS with multimeter and seems smooth through the range. Plug wires were new last fall, but I ohmed them out good and even switched sides to see if anything changed. I put the original BJYL tune back in just to verify that it wasn't a timing issue with the newer tunes, but problem was still there (should've known, but had to try).
I have tried to attach a set of logs taken the other day (Tunerpro RT V5). This was from cold start and the surge was there.
Any help or suggestions would be appreciated. I'm about to have to pay someone to check out the truck since I need it in 2 weeks and don't know what else to look at. IF this isn't the right place to post, please let me know. I'm still learning my way around.
I’ll look to see if I still have it. I replaced the original last fall and ran the new one on the old engine before the engine swap. Since it had a lifetime warranty, I replaced it last week to eliminate it as a cause. If it is the coil, then the first new one would have had to go bad and the new one put in last week had to be bad out of the box. If I have the old coil I’ll check it. Stranger things have happened.
Thanks for the suggestion!
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