DanScram

I've been at this for months now and can't seem to my get my fuel tables right. I've been able (at times) to get maybe 80% of my BLM's w/in +/-5 of 128 but I still have a few outliers in the 118-120 and 135-144 range. I tweak it a little and it gets worse. Also, I'll log a bin that was "pretty close" one day and, with no changes to the bin, it will be horrible.

I usually log data between by home and my office which is about 35 miles but, there is a 3000 ft. change in elevation between the two. Downhill most of the way in and uphill most of the way back. Is the atmospheric pressure change throwing me off? I try to stay out of the throttle as much as possible and keeping the rpm's below about 4100, usually below 3600.

Another thing, my morning drive could be at 30F ambient, afternoon drive at 50 or 60F. Does it make that much difference?

I've attached a portion of my "best" log that shows one of the problem areas.

Re-built 4.3L TBI, .030 over otherwise stock, MT, 16196395, BJFD, Advanced $OD v175.xdf

Any words of wisdom?

RBob

iTrader: (1)

You mention 30-over but otherwise stock. Does it still have the stock pre-heating on the air cleaner along with the intake manifold water jacket?

How is the driveability? Note that both the EGR being active along with the CCP will affect the BLM values.

RBob.

DanScram

As for the preheating, I do not have the metal duct/hose installed between the exhaust manifold and the air cleaner housing. I guess I don't know about the intake manifold water jacket - I made no changes to the manifold when I put it all back together other than cleaning it up a bit.

Diriveability is generally pretty good with the exception of some stumbling when accelerating from a stop a a little "chugging" at low rpm's and load. It is pretty gutless in 4th gear which I've been attributing to 35" tires, 4.10 gears, and steep mountain driving. I was hoping that would improve when I got around to the timing.

I do appreciate the benefit of the wisdom and experience of those on this board.

Thanks, RBob.

DanScram

I turned off the EGR and CCP but haven't been able to locate the pre-heat duct to re-install yet. The minor driveability issues mentioned above went away as far as I can tell. I did one log and adjustment but haven't had the opportunity to check the results yet. I'll keep at it.

Ronny

iTrader: (1)

EXT leak?

DanScram

Exhaust leak? I don't think so but I'll check. Other than hearing or perhaps feeling a leak, what is the best way to tell?

I hope to be able to do a nice long log soon to see the effects of turning off EGR and CCP. And, by "long log", I mean data collection...

Ronny

iTrader: (1)

header flange to ext port/head or header collector flange to ext pipe flange