I just installed new 30# injectors and a Holley AFPR. My fual pressure @ idle with no vaccum hooked to the AFPR and the line to the plenum caped off, is dead nuts on 43.5psi which is the actual psi rating for the exact injectors I have, just happens to match GM's specs as well. My timing is also dead on 6*.

Anyway, I did nothing but simply change the Injector Flow Rate in my bin from 19.76 to 29.45 and my BLM's instead of being below 128 showing rich, were way above that at like at 147!!!!! WTF? After about 10 mins of driving they go down to 135 or so but I have no acceleration what so ever, it's like I have a 50hp motor.

I figured I would be around 105 going from 19# to 30# injectors and that I would have to start tuning my VE to get it higher but why would they already be in the 140's???

I can't get it to idle smooth either, it keeps jumping around. I've reset my IAC, set my TPS, installed a new MAP sensor and EGR, replaced my pick-up coil and rotor. Once I get it tuned I have new plugs and o2 sensor ready to go in. I did all this because I also installed a new base manifold. The throttle body is also new, it's a 52mm TPiS unit.

 

Your VE tables are going to be off now that you've replaced the base manifold and the throttle body with bigger/aftermarket pieces. I'd put a fresh o2 sensor in and start tuning. I think I would expect exactly that kind of behavior (blm's over 128) from the changes you have made.. No better time to start tuning!!

edit: Just visited your website and noticed that you have headers, you should get a 3-wire heated o2 sensor. Get that first and then see where everything sits.

 

I've got a 305 though, and I don't even have my AFR's or my camshaft in yet, no way I should be lean with 30# injectors, that's where I was coming from.

My current o2 only has about 2K miles on it so I'll get it running fair with that then stick in my new one so I don't foul it up by being too lean or rich. I didn't get a heated o2 because I'm installing a WB o2 in a couple months when I do install my heads and cam.

And talk about pissed I've been going through hell today to get this pig idling right and it all turned out to be that my BRAND NEW MAP sensor from the GM dealership was bad Now my baby idles better than ever! However I won't accelerate for crap until I tune my bin...

 

What were the BLM's at before this change??

 

You'll never believe this!!!! I just went for a drive after replacing my bad MAP check this out:

TPS: 0.53v

Idle in Gear: 600 - IAC Steps: 0
Idle in Park: 700 - IAC Steps: 0

EXACTLY what my bin wants my RPM to be at these times, it's so perfect if the IAC moved 1 step it would effect it!

BLM's: Idle 123 - 125
BLM's: Driving in VE 128 - 131

MAP kpa @ Idle: 30 - 35

Only 4 knock counts during a 10 miles distance!

Only one problem though, it bogs during acceleration if I get on it even mildly. I think that's my PE right?

 

More likely AE I'd think. Check your TPS threshold for engaging PE against the actual TPS when you feel the bog to see if PE is even coming on. If not it's definitely in AE.

 

Your're right! Thanks! I'll work on that next.

My 600RPM idle in drive while perfectly smooth, seemed just a tad too low so I raised it to 650 and it feels much better now. I'm more confident in a always smooth idle RPM in gear now with now worries of stalling at a light.

 

How'd you determine that your new MAP sensor was bad?? Was it reading differently? If so, how?

 

Actually out of luck I just replaced it with my original one and then it just started running great. Total chance, I didn't happen to notice what the kpa's were on the new one while data logging. I guess you can just say stupid luck...