I have a stock 305 that I converted from carb to TBI (7747). Runs good but at closed loop idle the BLMs go down to 102 which is the limited. I lowered the limit to 90 and it still wants to go more becasue it drops to 90. I have the correct injectors, fuel PSI is 11.
I was reading another thread that said by lowering the VE tables will not work because the CL BLM will drive the fuel back to where the O2 constants indicate.
I have tried lowereing the O2 idle constatn and it makes no difference. any ideas? I have thought about changing the injector constant.
I was reading another thread that said by lowering the VE tables will not work because the CL BLM will drive the fuel back to where the O2 constants indicate.
That was more of a reference of trying to run at a different AFR.
Cams with overlap make the O2 read lean and tend to add fuel to correct it.
Your on the other side of that problem.
Your issue sounds more like the fueing tables are just too rich.
Jump into the tuning guide up there in the sticky and try some of those methods for getting the base air/fuel inline.
Kind of seems like the base BIN you're using was not for a 305 TBI with those injectors. Is it a fairly mild 305, or does it have a huge cam?
In 7747, you'll have to modify the base pulse constant first, I think (been a few years since I did that truck). That'll get you in the ballpark.
__________________ - Jeremy -
EFI Calibration Engineer, Software Designer, and System Parts Manager (Fuel Injection Technologies - FIT - look for "Geely" or Shanghai "Maple") - still in China since Nov '04!!!
since 1994? - 86 Z28 - rusty, tired, and in storage ;since 2003 - 89 GTA - also in storage now needs paint - badly
GTA stuff: Alston SFC's, wonderbar, KYB AGX's, '00 TA seats (off color a bit), 1LE brakes, Hooker 2055's and catback, Coan 2600 conv, Transgo shift kit, other stuff: (I think I'll use the 355 with forged TRW's and nitrous gapped rings - has LT4 hotcam, AFR 195 74cc ~ 9.22:1 CR, pro-mag 1.6rr's, Super Ram, 58mm BBK, looking for inj, maybe a new trans) on hold until I get back to the states - perhaps Fall '08 (yeah right) - oh yeah, bought a vortech supercharger, and plan to water/meth spray it.
Autoprom, TunerPro RT, LM1 user
It is a stock 1985 305, I just put in a comp cam 12-249-4 ; 0.05 duration: 206 intake, 212 exhaust, lobe lift .289 intake; .296 exhaust, 112 deg lobe seperation.
I am assuming the BPW constant for the 7747 is at address 2b4 and is labeled as "BPW Const for EGR off" in TunerPro. I am using bin ARPC7509 and the constant is set at 148.
i have researched the numbers off the injectors I have and they are for the 5.0L. If I change the constant I am assuming I will reduce the number to reduce the pulse width, right?
;since 2003 - 89 GTA - also in storage 
