I've been chasing my tail for a while now, trying to find why the motor drops off at 3000, at almost any throttle position. (383, w/ mini ram, and 224/230 cam) The injectors are 32 lb, and that value is in the scalar data, fuel pressure remains steady @46 psi wot. Per data logs, the VE's from 3000 on up range from 85 to 99.6, with BLM's up to 142 (730 ecm,8D mod, PE disabled for tuning) To my befuddled brain, this says I'm running out of injector capacity, but I don't think my combo should require any more. Is it possible the ECM is going bad? The BPW #'s increase with rpm, peaking at 8 or so. The plugs are all uniform color, a little tan. Forgive my rambling here, but any help or opinions would be greatly appreciated.

 

No just need to put a wideband on it, re-enable PE and tune the WOT fuel with the AFR RPM PE fuel table.

 

Thanks for the quick reply, a wideband has always been on my list, it may be time to buy one. From the description of your setup, we should be comparable in output. I don't understand how PE being enabled would allow more fuel if the VE's are already at max from 70 to 90 kpa. I'm not disputing what you say, I haven't been in this long enough to question anyone, I just don't understand the why.

 

The VE tables in closed loop will never push the ECM to deliver the ~12.5 - 13:1 AFR that the engine probably wants for max power.

The ECM in closed loop (provided the stoichiometric constant hasn't been changed) will always attempt to deliver 14.7:1 at any operating condition (notwithstanding things like decel enlean or accelerator enrichment).

So for max power you have to enter into PE where the ECM ignores the O2 sensor feedback and delivers the pre-programmed AFR set by the user.

 

I understand what PE does, trying to drive the system to a lower AFR. but if the system can't achieve 14.7 when not in PE (VE's maxed) how can it add more fuel to get to 12.5-13.1 AFR? I think my thinking(?) is wrong, I have been assuming that VE values represent 0-100% of injector duty cycle, and that the max BPW value I have seen (8) represents a duty cycle of 80%, a value I've heard should not be exceeded. What do these values really mean?

 

this thread may be the reason the PW peaks at 8 ms:

https://www.thirdgen.org/techbb2/sho...hreadid=276420

RBob.

 

I'll have to look at that when I go home, but it looks scary. Isn't there a button I can push, or something I can jump out?- just kidding, thanks for the reply.

 

I see why I never ran into that issue, running S_AUJP.

 

Since I'm not smart enough to modify the 8dMod xdf. is it possible/how difficult would it be, to switch to S_AUJP?