Magman

iTrader: (6)

I'm new to tuning and am working on my lower KPA VE tables right now using TunerPro 4.0, Prominator, 7730, S_AUJP.CCP. I have less than 20 miles on my newly rebuilt 383 HSR, 230@.050 cam with SVO 24lbers.

My question is, while I'm driving around data logging when I decelerate from approx speed of 20-40 mph I immediately see excessively lean BLM's. It goes away quickly when I apply throttle. Is this norm or should I be concerned with adjusting enleanment on deceleration?

Ronny

iTrader: (1)

excellent question. maybe someone that knows will jump in here. deaccelleration enleanment which i assume is fuel cutoff i see vividly on WB02. goes super lean. i am probably wrong but i thought no fuel correction takes place so BLM's would not be affected? also when DE comes in it is tipically high map and i was informed(JP) there is insufficient time for learning to occur anyway so i should not concern myself with VE/BLM's in that area nor the resulting high MAP when i accell hard from low map low rpm cells. i pulled out VE there and added back in at AE TPS and AE low map. inconclusive result and not yet studied it.

my Q is can provide a max A/F when this DE occurrs? like cap it to 20/1?

why would i want to do this as it saves on fuel cost(93 octane)? i think it dries out my intake so that when i envoke AE once more i need to fill plenum(enrichen) to prevent bog or bog occurs followed by AE overcoming this dry state in manifold. maybe much of the atomization occurrs from shearing off wet runner sides and wet TB as well. TBI related issue?

dimented24x7

iTrader: (2)

I wouldnt worry about it too much. The PWs get really short when decelerating. Above 35 mph, Decel Fuel Cut-Off should be in effect, which cuts the fuel altogether.

dimented24x7

iTrader: (2)

Been awhile since Ive played with this but there are some parameters in the stock cal. designed specifically to help provide extra fuel when your tippping in after decelerating.

Ronny

iTrader: (1)

Dim: i am working on an AE bog. i pulled out 20% VE in higher map cells 800/1200 rpms and added in ae map only 0-20-40 map. seemes to help but still that lag(slight bog) before AE comes on. i added more AE at 0-25% tps but have not yet installed bin as i have a CE problem past week.

is TBI bog sensitive with larger TB and intake and intake runners/ head?

dimented24x7

iTrader: (2)

One thing to keep in mind is that the VE table is for steady state (or nearly SS) fueling. The AE is there to handle the transients. Id try to keep them seperate, IOW, dont try to use the VE to handle the AE and vice/versa. Get the VE dialed in, then tweak the AE.

JPrevost

What are your BLM's at in the other cells? Under deceleration the engine is pumping VERY little air through the motor so the lean/rich really isn't all that important unless it's backfiring or giving you fits. The real troubles come when under load the engine is too lean or overly rich.

Yes TBI is very sensative to AE because of the wetflow.
I agree but sometimes it's harder getting the AE all squared away and so in a time crunch VE table AE is an acceptable temporary patch. I've done it more than I'd like to admit but mostly limited to the 8746. The 7747's AE seems to play nicer and it probably has something to do with the whole TPS AE routine RBob pointed out a while back. In those cases I've left the TPS AE alone and spent all my efforts looking just at the MAP AE settings. That seemed to produce the best results.

Magman

iTrader: (6)

Nevermind, I was receiving false info. Just realized my TPS is reading 1.74v with throttle closed and eng off through TunerPro. Reading with a Multi meter shows .54v fully closed. When I cycle the throttle, Tunerpro shows the TPS reading completely backwards and the multi meter reading accurately. I guess that leads me to a bad ECU / ECM?

Anybody know where to get a new one for a decent price? Salvage yard?
Thanks

dimented24x7

iTrader: (2)

Id double check that your getting the right value outputted. Ignore the converted value and see if you can post the raw tps values from the logs, if possible.

Ronny

iTrader: (1)

i responded to this is tuning therory for small plenum. i believe the above it has helped somewhat.