I'm in need of some help tuning my new engine. Been tuning it a little and have a little surge with the new engine around 1600-2000 rpms on part throttle acceleration. I've added about a degree of timing and fuel by means of accel vs. tps. It fixed the 1000-1400 rpm surge but I still have the 1600-2000 sometimes. So, should I increase the fuel a little bit more and up the timing about degree?

Setup: 383, 10.6:1 compression, hyd. roller XFI 274 grind, HSR unit, AFR 195 heads.

 

Usually a surge at part throttle is a good indication of a lean mixture. Do you have the ability to see what the oxygen sensor is reading? I'm not sure on what to recommend with the timing. I'd richen it up a little then play with the timing a little bit to see what it likes the best. That should be a pretty killer setup in that truck as long as you aren't lugging it down towing something . On a side note, do you have some traction bars or something to control wheelhop? My dad's '90 C1500 that he and I rebuilt a 350 for and fixed up always had a problem with that when I would spin them a little.

 

Do you have any kind of datalogger?? I.E Winaldl or tunerpro? And a laptop? If so then you should beable to see what is going on while you drive in that range and beable to make adjustments from there. If you dont have something to datalog with I would highly recommend you invest in a cheap laptop and go from there. It will make life alot easier. Hope that this helps??

 

Quote:fuel by means of accel vs. tps.

that is acceleration enrichment AKA pumpshot. i bet you are just needing more fuel there in tables.

 

You talking about the accel vs. tps table or VE table.....been working on it and it hasn't gotten better. I can take it above 2k and its fine but 1400-2000 is bad/surge about 200-300 rpms or so dip.....drives me insane. I changed the Stot. to 14.5:1 to try and richen it up a little that way and increase the accel vs. tps from 0-25% throttle from 3.13 to 5.00 with no effect. I'll get a wideband run tonight and see what's going on exactly. Thanks for the input so far...keep it coming, I check plugs last night and I'm going a degree colder...my FR5s are a little hot for the engine.

 

I do have a laptop with TunerPro RT and basically all this time been tuning the engine by checking spark plugs and with my wideband.