Is there a table where I can set minimum pulse width with an ebl flash to set up as TBI. This is a 4.3L lb-4. It is setup to run multi-port fuel injection:four barrel intake 1000 CFM throttle body and GM sensors. Using factory GM Sy/Ty injectors (flow data of 31.46lb/hr@43.5 psi, the actual fuel pressure in truck is 30-31psi at idle with regulator plugged in and roughly 39 un-plugged. ) Using Rbobs advice I wired two sets of three injectors to each injector driver. The problem I'm running into is once I run my ve learns it's trying to lean out idle to the point that the injector pulse width flashes between zero and a value I can't read because it flashes so fast, injector duty cycle is reporting at zero and then flashing 11 and Reporting at zero. As the vehicle runs consecuative ve learns and leans the idle it runs worse and worse and has developed a considerable stumble / misfire. If I load it back to the initial tune where it's running rich at an idle it runs perfect. At this point I believe that the injector pulse width is below minimum and that is why I'm experiencing idle issues. I am considering trying to drop the fuel pressure lower and relearn it to see if I can get the bmpulsewidth high enough that it's compatible. Does anybody have any ideas? I can send you the current tune file to look at as well as a short video of what the what's up display shows at idle. It is also showing a spark knock at idle but I don't know if this is because the actual mixture in the cylinder is far too lean. 1991 s10 4.3 excab 2wd.

 

Yes, it is the:

INJ - ASync Transition PW - TBI Only

Along with the:

INJ - Min/Max Async PW

Once the sync PW gets below the transition PW, the ECM enters async firing mode. When the async PW is lower then the Min Async PW, the ECM accumulates PW values until it is large enough to fire the injectors. Note that in async mode both banks of injectors fire at the same time.

For a smooth transition between async and sync firing modes the injector compensation values need to be correct.

A data log will help in seeing what is going on. Can do a playback of it in slo-mo, or via it as a dump log file.

Can run open loop idle and eliminate the closed loop change during idle.

Likely false knock, which at idle shouldn't retard the timing. But still should be looked into.

RBob.

 

streetlethalgta@gmail.com

- Rob