Finished and installed my 383 into my truck (see spec below). When I tried to run the engine at 2000rpm for 20min, for the cam breakin, the engine rpm kept falling off unless I feathered the gas. I had the chip set with no egr, stock advance, remove knock retard, 115bpw on 454 tbi and 80lb injectors, everything else was stock on the chip. When I took it for a trial run the engine would not respond at all and would fall on its face badly. I think the pe has to be bumped up so it responds better? I am running data master for a scantool and it showed the lt blm to be lean when I tried to accelerate. I don’t know what to do with the ve table at this point and need your input for the what I should be doing to resolve the situation. What happens if the bpw is to low or are the injectors just to big? By the way it does idle without surge. I did bolt this 454tbi onto my existing 350 to ensure it was not going to give me troubles on my new engine. I got the iac and tps connected properly and changed the bpw to 112 for this trial and it ran a little rich as per the scan tool. I thought It would of ran allot better on my 383 since I took the wiring bugs out of the equation trialing the tbi on my 350. A little disappointed with how this new engine is reacting, did not realize how much the stock eprom would not operate this new engine as per fuel and possibly other factors. As for these other factors I am not sure what to do at this time. Did not touch the stock fuel pump or fuel reg. I do have an adjustable regulator but have not used it yet. I figure why increase pressure with the larger 80lb injectors, they use them on a 454!

383 stroker, 64cc 23deg alum. trickflow heads c/w 454tbi 80lb injectors edlebrock performer intake and adapter, roller rockers, cam is an extreme 4x4 comp. Cam. 12-235-2 grind ( .447/.462 lift, duration 210 218 lift @50, 111 lobe separation) . unit has hypr. Flattop floating pistons, eagle cast crank, 5.7eagle rods. 10.2:1 comp. Headers c/w 2.5” flowmaster exhaust. Pcm-85definition file.

 

I've run into "about" the same problem. I swapped to SD with my current setup already in the car so i haven't had anything to start with. The best thing i could come up with was to start with something as close as possible!, that was a 90vette chip. From there i adjusted the injectors, turned egr off, disabled a few other things. The FIRST thing you will want to do is to lock the BLM's to 128, start the truck, let it warm up until closed loop is entered. From there i would let the truck idle. The BLM's will stay at 128 but the Integrator will change accordingly(this is what you will use to tune). I am using diacom so i got some good idle integrator numbers. Then i opened tunercat and adjusted my Lower VE table accordingly. From there i used the graphing function of TC to "guess" on making my evenly sloping graph, that way i know i would atleast have enough fuel in the up rpm/load ranges. All of what i am saying is in Tim's P730: Part Throttle tuning article.
I know it is for TPI but the same basic principles SHOULD work on your TBI setup.

Brendan

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1987 IROC-Z L98,SuperRam,EB 6085's,LPE 219/219 Roller, Crane 1.6RR, EB TPI Base, 58mm TB, ADS 24#, AFPR, K&N, EB TES, Catco Cat, 3" Borla Cat-Back, Accel cap,rotor,distro/other crap, MSD 6AL, MSD Blaster 3, Aluminum DS, 94 Disk Rear, Adjustable Valve, Precision 3.73 Gears, Sub-Frame Connectors, Hotchkis Lower Control Arms, KYB Shocks/Struts, Suspension Techniques Lowering Springs, Polyurethan Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm,

To see the ROC, Check out the webpage Here

 

i resolved most of the problem by finding out my timing was out. i also increase the pe %tps to a 454 bin table, what a difference. the engine responds much better and sounds great. my only problem is when i when tried to set the initial timing to 0deg, i unplugged the pcm tan/black strip wire on the firewall, the engine stalled. does this mean my timing is still retarded to much? also, the long term blms and shortterm blms are jumping all over the place. i would like to set the ltblm to 128 and tune the stblm but i cannot understand how to do this. some of you explained some but! i have a $85 def.file and there is no provision for locking the blm to 128, i have to go into the hex and do it.it i don't lock the ltblm to 128 should i then be tuning the fuel curve to the ltblm or shortterm blm?