8625 $E6 Open loop tuning help

[zuk1972]

Hello My Name is Steve- is been awhile since ive been on here .I recently upgraded to a new shortblock before I really got ahold of my tune .A few things that were holding me back were a worn out engine ,no wbo2 ,and a cracked head . I have since got all these things replaced and am ready to prepare wbo2 tuning .I had trouble finding info on the wbo2 integration to dashboard of tp5 as my truck doesn't have a egr pintle it has a different egr schematic and it is called something else but I figure I can try and tune mostly WOT by watching guage and making adjustments . A few questions I have is what paremeters do I look for to increase and decrease fueling for open loop please have patience and I have looked for this info many times before and a lot of what I found applied to different ecm and masks but not a lot of info on the $e6 and 8625 ecm. My shortblock was just upgraded to a 383 9.5cr I have always had the vortec heads and shorty headers no cat 454 tbi @ 20psi lt4 hotcam hurricane singleplane 4 bbl w adapter 373 gears vortec fuel pump with external fuel regulater . The blms are off slightly but I plan to tune closed loop and fix those with daves ve fixer and have done that before no problem .its the open loop I need some advice with . Thank you for any advice in advance many of you have helped me a lot in the past and I really appreciate it.

[sturgillbd]

You adjust fueling in open loop using your VE tables as you do in closed loop. Your WOT fueling is based on the VE table along with the PE tables. You really need to get the WBO2 signal into the datastream so you can tune via your datalogs. The difference between Closed and Open loop tuning is the PCM does not attempt to correct fueling in open loop and you won't have BLM data to tune by. You tune by what the WBO2 puts into the datastream and make your corrections from there. HTH Brian

[zuk1972]

Okay so I max out the enable closed loop min temp and adjust the Ve same as cl then pe tables for wot . I did set my pe /ae based on a thread I seen with Dave's advice on vortec tbi so if it's lean @wot now it needs more pe then I started with at wot and I'm looking for 12.5 afr all times if rich then less pe.My pinouts seem to match a 94 though the truck is a 93 so I'm missing the pinout that people reference the wire going to egr is called something different than egr pintle too do I use the egr sensor lead wire and not common or shared ?it doesn't have a egr I can just tie in at wiring plug under hood but I'm unsure which wireOne other question is that is there a open loop pe adjustment or is it both cl and open loop pe for wot?

[sturgillbd]

Looks like you use pin B16. Here is the pinout in an excel spreadsheet. Hope this helps. Its says for 16197427 but the same pins are used in a 8625

[zuk1972]

Looks like you use pin B16. Here is the pinout in an excel spreadsheet. Hope this helps. Its says for 16197427 but the same pins are used in a 8625My plugs on ecm match up with colors on this chart for a 94 it must be a late 93 model .http://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/pcm-connector-pin-out-2E1 is a egr solenoid that matches my plug and colors . Mine has no wire at b16 so that's why I'm nervous

[sturgillbd]

B16 would only be in a 454 or a 4.3 V6 harness because those are the only vehicles that used a linear EGR. You will have to add that pin into your harness to datalog your WBO2. Brian

[zuk1972]

B16 would only be in a 454 or a 4.3 V6 harness because those are the only vehicles that used a linear EGR. You will have to add that pin into your harness to datalog your WBO2. BrianYes -that makes sense now this was originally a v6 truck with a v8 bdjy memcal that explains it .so do I use the egr solenoid wire in this case ?

[zuk1972]

Hello again,Im preparing to do a datalog and had a few more questions.Its 10:1 rich in open loop warm up idle and driving and goes down accelerating depending on weather temps until warm up .then closed loop its in decent shape but i plan to use davew's spreadsheet again to get it much more dialed but again after warm up when it drops out to open loop at 3600 and up at wot warmed up its at 11:1 afr.Is what your telling me pe will fix the pre closed loop cold start richness issue?Do i just adjust the PE afr vs rpm table and raise by watching actual afr on wideband?

[newellshk]

I would concentrate on getting your VE table correct before worrying about warmup/choke AFR. It sounds like your VE table is too high if you are getting 11:1 AFR. I would adjust VE until your WOT AFR roughly matches your PE AFR vs RPM table(ie if it's trying to hit 12.8:1 AFR as commanded by the PE AFR vs RPM table but really hitting 11:1 AFR then your VE is about 15% too high at that MAP/RPM). Once your VE table is correct you can then adjust your actual PE AFR directly via the PE AFR vs RPM table, and you can mess with your warmup AFR by adjusting the Choke AFR vs Temp table, Choke AFR Decay Time... etc. I haven't personally messed with the choke tables however.