Figured out my low rpm chug/misfiring

[Spareparts]

The only thing i see wrong is chevy's are not supposed to have that kinda access to the distributor

 

[L31MaxExpress]

I can tell you the van was not overly happy with what I did with it today. I am moving my mom 100 miles from where she lives. I pulled a 24 ft enclosed tandem axle, tight packed with heavy wood furniture and heavy boxes. I yanked the middle row seats and had both the center and rear of the van packed as well. I put the shifter into 3rd, I accelerated at moderate throttle up to speed and set the cruise at 65 mph and just loafed along. The van was sure to remind me of how heavy the load was though. It hit 2nd on a couple of long grades and still held around 65 mph on cruise though. I hate to guess what the thing would have scaled, my guess would be about 2-3K more than it is with my travel trailer. I had to back down her gravel driveway loaded and all 8 tires were slipping a bit. On the way back despite a fair headwind I was able to tow the empty trailer in overdrive most of the way, loafing along at 72 mph and 1,900 rpm. Averaged 9 mpg for the trip, not bad for a gasser moving probably 15K overall. At one point the trip average was around 7 mpg when I looked at it fully loaded. This trip reminded me of how badly I need to get on putting 4.10s in the thing as well as the 6spd swap.

 

[Supercharged111]

Chop chop muchacho with that 6L swap. You can live without the gear swap simply by holding 5th as a holdover.

 

[L31MaxExpress]

Chop chop muchacho with that 6L swap. You can live without the gear swap simply by holding 5th as a holdover.

My biggest complaint with that much weight is actually the part-throttle 1-2 shift though. At about 30-60% TPS, I need to stretch out the shift points a bit more and make it easier to get back to 1st as well as just make it downshift more easily in general. I currently have a lot of dead pedal where the MAP is near barometric and you have to increase the pedal another 10-30% to get a downshift. It is not noticeable with an empty van, but it is with a load. The cam in the 383 really does not enjoy slugging it out at low rpm all that much. It is too easy to unlock the converter and not easy enough to force a downshift. On a couple of steeper, longer grades on the way home, I pulled the shifter down the 3rd on the flat land prior to hitting the grade, then upshifted as I hit the top. 3-4 shift under load with the TCC locked about knocks your teeth together. On a flat stretch, unloaded on the way home I glanced at the OBD2 data on the radio head unit and was only pulling about 6-8 in/hg vacuum at 1,900 rpm. Catalyst overheat protection was also dumping massive amounts of fuel at a couple of points, I actually felt the engine lay over a bit and the wideband was nearly pegged rich. I was not anywhere near PE Enable TPS either. Definitely has some room for improvements left in the tuning as well.

 

[L31MaxExpress]

Chop chop muchacho with that 6L swap. You can live without the gear swap simply by holding 5th as a holdover.

Hey supercharged, with the way you have your PE set how much of a soot ring do you get around your exhaust towing heavy? Mine looked like a diesel back when I had it set the old way and was hitting PE before downshifting. This is how clean it seems to be burning now. No soot ring at all around the exhaust, just a light buildup in the pipe. I figured the first 2" of the pipe would have a jet black ring as hard as I was working it based off the way it once would look. My tuning preference has change now days to unlocking and downshifting out of load rather than slugging it out and hitting PE.

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