Wierd BS3 fuel situation

[jpwalt1987]

Guys,

Something weird is going on with my Gen1 BS3 system. While trying to dial in a street tune (93 octane no alky) I found that i was nearing VE values in the 88 range at 19-20 psi and 18* timing. I kept increasing the VE numbers trying to get the AFR down to 11.5 but it doesnt seem to budge at the higher rpms. I have the VE at 95 now at above 4700 rpm but havent got a chance to verfiy that the higher VE numbers have helped. I did notice that I have a correction factor of -10.9 even though I am commanding more fuel. Now here is where it gets stranger..... 10.9 is the maximum POSITIVE correction I have input!! The maximum negative correction is -5.5 under full load. I find it to be a strange coincidence that instead of adding fuel, it is taking out the same percentage that is in the positive correction table.

I have some 55 lb/hr injectors and a brand new DeatschWerks pump all hotwired and new filter etc. My gross injector pulswidth at 20psi/18*timing/11.3 afr was 19.2ms. It did get leaner (12.4) as it climbed to 5550 rpm. I haven't been able to spin the engine any higher than 5700 rpm. On the O2 correction it does show -10.9. Do yall think that it really is trying to ADD 10.9% even though it has a minus sign in front? I am gonna check my FP as soon as my new seals come in for my gauge. It was set at a base of 43 vac off. I would think that the DeatschWerks pump would be able to keep up regardless though. This is a "right now" tune. I have another car that I am swapping motors with soon and just want this one to be sorta fast but safe until I can get the other car ready for this motor. The motor I am trying to tune is a DLS built 3.8 with ported GN1 heads and a 218/218 roller cam. Not looking to set the world on fire right now, just want to max out these 55s and stop there. Drive it a while and prep the other car. Thanks for any help.

BTW... the wideband has never seen anything but unleaded fuel.

 

[HighPSI]

What is your Target A/F at that point in the MAP?

 

[jpwalt1987]

Cal, the top three rows of the AFR table are
11.2
11.5
11.5

 

[HighPSI]

When you are having this problem, are you in the top 3 rows? I was wanting to know your Target A/F at the point where you are having problems. Also, what is your injector duty cycle?

 

[jpwalt1987]

Cal,
yes I am in the third row from the top on the afr scale commanding an AFR of 11.5. I put it in open loop and the car overall runs way better. I was able adjust my VE numbers to make my AFR fall in line to where I want it. When I put it in open loop I wanted to be safe so I had VE of 108 at 17-21psi of boost. The AFR numbers went pig rich. I then started decreasing the VE in that area to get the afr to 11.5. Something is wrong with the correction portion of the program or hardware. I remember Dan Strezo tell me that Joe Lubrant fought a problem like this when the gen 1 BS3 came out and that something was pinned out wrong. IDK. I do know that it runs great in open loop. As far as duty cycle goes, I am in the ball park of 85%-90% @ about 18-19 psi. It is still a bit rich though. I still have my knock detector going off at around 5300 rpm even with a super rich afr and 18* timing(verified). I believe that is valvetrain related. It is kinda noisy. Supposed to have Morrel lifters in there but not sure....sounds like Comps. ;~) Thanks for any help and ideas!! The next car will be getting an XFI for sure.