Engine Issues after deleting DOD/AFM on rebuilt engine

[buddyhotrod]

That motor really looks good.

 

[NathanS]

To get it running on all 8 until I get it tuned I plugged in the old valley plate and zip tied it to the firewall. Not sure if I should be worried but it backfires every now and then. Haven’t drove it much yet. Still need to break in the rings.

 

[iamdub]

Ehrmahgerd. lol

I must applaud your ingenuity, though!

I'd be concerned that the backfiring is from the four AFM cylinders flooding. Or would it be running lean? Hmmm...

Maybe try to drive it in such a manner that keeps AFM from activating to reduce the backfiring and chance of damage?

 

[NathanS]

The tuner suggested that I plug in the old plate. Can’t take credit for that one. Texas speed said its backfiring due to AFM and not being tuned yet. Should be getting it tuned next week. Hopefully.

 

[NathanS]

My schedule didn’t allow me to take it to the dyno. I got a tuner to do it locally. Works at Steve’s Automotive in Saucier MS. He used HPtuner. Deleted AFM, changed shift points and line pressure. Changed a bunch of stuff I don’t know about. Air. Timing. Idle. It idles and runs really good. Very nice guy.

These guys completed the exhaust after the speed engineering y-pipe.
performanceofgpt.com
Outstanding customer service. Look them up if you’re in the area.

 

[NathanS]

I went with a 3” single in/out 18” magnaflow muffler with 3” tubing. I’m liking it more and more. Has a deep growl at idle but opens up at WOT. No real noise cruising at 75. Maybe a little from the headers.

 

[Ls2jorge]

Any Update on your build bro? Any vids of the Tahoe

 

[NathanS]

No vids. It’s running good. I’ve put about 5k miles on it so far and I’ve towed three trailers. One weighing about 5500 lbs. The exhaust it a little loud but t sounds mean. Averaging around 12-13 mpg.