Have a seemly lean condition almost as if fuel is being cut off or the added air from the increased tps opening is not being accounted. This occurrence is around 5% TPS opening. Doesn't matter on temp or rate of opening be it a slow progression or a rapid opening. If throttle is held open ecu/ engine seems like its trying to correct itself resulting in a surge. Obviously, its going lean. Looks like when the MAP drops below 60 -55 and heads towards 40 kpa this occurs. Its like an on / off switch. Yes, the VE tables needs to be worked but this seems to be elsewhere due to the on/ off behavior vs rough running/ digressional slope behavior.
After playing around with my initial trail & error tunes, went and started with the stock ecu base file and converted it to SD. Left timing alone. Did one with base VE and one with VE * 1.25. Log for the later tune didn't pick up all the channels. The 1.25 chart also had the correct injector flow rate inputted. Do need to redo the scanner channels to get more data.
AFRs much better in the 14.5 +/- 1.0 range depending on engine speed and temp. Idle is better. Still have the same tip in issue. Feel its something aside from the VE table being its consistent regardless the tunes/ changes to the VE and timing table(s). Even tried some extreme valves. Something stupid but overlooked. Tip in can be very gradual and pause as you go, but once that certain spot is reached, it goes dead lean. I say dead lean as my WB gauge only goes to 18 and if throttle is held open (say >50% guessing), engine will become quiet as if the injectors are not firing. ECU does a decent job trying catching itself if you open and close the throttle (feathering), but ultimately, throttle will need to be under 5% tps and idle resumed. Is there a MAP or ETC table or parameter that's being missed? Maybe a MAF table that its looking to find once its off idle? Perhaps its not switching into SD mode once off idle and is not seeing the VE table?
Wonder if such a thing as flood clear mode is kicking in? Have that set at 85% TPS. Would the LS3 MAP sensor have anything to do with this as its range differs from the LS1 MAP? Set the parameters to 128.13 w/ -0.31 offset. Anything else needed to be done for this conversion?
Background info:
Checked TPS, have 5V , Ground and 'linear' signal output.
Accufab 4150 throttle body which uses the LT1 TPS. 0-5V . Although WOT on TB is only 4.14V. Closed is 0.43V. This correlates to a TPS of 0-100% with 0411 ecu.
ECU (0411) is pinned accordingly to factory manuals for sensors needed/ used in stand along operation. Fuses, relays, powers grounds, ect.
Engine is a 455 based Pontiac in a 78 Trans Am
Yes, firing order is different. Injectors and coils have been repined on the ECU accordingly. (3,4 & 7,2 cylinders switch). Could have changed that in the ECU but wasn't aware at the time I was doing the wiring.
ECU is from an 01 or 02 Suburban 5.3 which was flashed to SD 1 bar & removed VATS. At least that was I believe I did. (fairly basic operation). Followed a tutorial (https://www.youtube.com/watch?v=vAQhoETdsRg) on disabling fuel trims, Fuel cut off, torque managements, ect , ect.
This is a continuation of the below thread which has the tunes & logs posted.
https://forum.hptuners.com/showthrea...694#post576694
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Originally Posted by TurboR1
