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I need some help to learn how to tune. Thanks for any help.
I have recently installed a TPI fuel pump and set AFPR to 17psi (untill I get a better spring). DC% is now 90% at WOT 4400rpm. (stock it was 110%)
1. The car is probably running wery rich in Open Loop, it has little hesitations followed by little black clowds.
What should I do to reduce fuel in Open Loop?
2. SA main table. I have been reducing SA in the areas were I get retard.
Not sure about my smoothing skills, ... skills.
With the higher fuel pressure the AE needs to be reduced. Can change it by the ratio of the increased fuel flow. If using 55 #/hr injectors (stock 305) then at 17 psi they will flow:
= 55 * sqrt(17 / 13) = 62.9 #/hr
55 / 62.9 = 0.87
Reduce the "AE - TPS PW" and the "AE - MAP PW" tables to the ratio 0.87. Can do this by highlighting all entries, toolbox, then multiply by 0.87. that will get the AE back into line.
The O2 sensor action is OK. In the -1 picture the O2 starts out cold. It's value is 451 mV. During the first throttle stab the O2 is getting some heat in it and is waking up. At 13 seconds the O2 starts to swing rich/lean.
In the -2 picture the O2 is alive and well and the engine is running in closed loop. The ECM forces the O2 to swing rich/lean while in closed loop. It is the job of the proportional gains to do this. this is done to keep the cat happy.
The picture -3 is interesting. Note that the O2 sensor voltage increases as the throttle is opened. Then falls off as the thottle is held open. This is a sign of too much AE. How much too much is difficult to say when observing a NB O2 sensor. Make the above change first, then see how it is.
The sudden jumps in RPM are most likely from either the TCC unlocking or the transmission downshifting.
Yes, VE learn is a great help for someone like me, makes me wonder if I should do VE learns every thime I make little modifications in the SA main table or if I can skip a few.
"BPC-BPC vs VAC" table is set to 115, according to the Excell SS BPC table values for 17psi FP.
The picture -3 is interesting. Note that the O2 sensor voltage increases as the throttle is opened. Then falls off as the thottle is held open. This is a sign of too much AE. How much too much is difficult to say when observing a NB O2 sensor.
I still get that figure, were should I start lowering AE?
Quote:
Originally Posted by RBob
It is at 85% DC and .45 BSFC
Consider a FPR that can be vacuum referenced. Works better when set up to vary fuel pressure to the intake manifold vacuum.
RBob.
What VAFPR part# would be best? the ones I found all loock like year 12008 intergalactic turbochargers
Is there by chance a VAFPR that mounts at the stock location?
Last edited by thomas1976; 06-02-2008 at 06:55 AM.
AE is a juggleing act for sure. I would say make small changes to base EBL.bin and check the drivability. Today I pulled 61 usec globally out of my AE-TPS PW as I was seeing 9.5/1 on a fully heat soaked manifold. WB was not required as it was felt rich SOP. This is not a TPS movement to 100% but more of a reasonably sane but quick acceleration from 0-35. I will expect to see a difference. I probably have 66% of my AE in the TPS and remainder in the MAP. I do not have IAT control at this point in time. That is important for AE control as well. My manifold tends to run cold especially when cool environmental temps. AE seems just right when coolant hits 185deg then seems excessive after a 25 minute drive. I also made a small change in the filter values. Lower filter # increases the duration and volume. I increased the # so as to bring in AE sooner trying to overcome a lag. There is sooo much written on AE. "search".
First off I run CL with NB02 active. I believe the best practice on a new unknown modified setup is to determine what fuel pressure is required for your engine to provide a safe A/F at WOT. Lets say that is 12.3/1 on the safe side. With that info in the BPC(fuel pressure required/inj size) one can then approach the easy steady cruise BLM and get that in line. That is easy with VE Learn. Along with that one can look at the open loop A/f ratio tables and be certain they match the observed A/F the WB is showing. I will say I am commanded OL to say 13.9/1 at 140-150F and observed is around 14.5. I trust the WB is 99% accurrate. I am OK with that as car is drivable at cold coolant temps. I cannot get a read on choke function nor crank function as WB is warming up. But the cold start is OK. Lastly is the AE routines and this is always problematic and frustrating at times. For me I have a cold manifold (Holley Projection TBI) with larger injs 80 lbs and a 7.4L TBI unit. That package is more difficult to get it right than mild mod to stock. I like to work lean to enrichment with AE. Lean pop then add AE till it is better. I have IAT setup but for reasons I cannot yet determine is is not functional! IAT would be quite beneficial on my intake. When I first started tuning I used Tunercat with a 7747 ECU. All I had to work with was AE MAP and AE TPS. Simple for a beginer. Also the tables were less in resolution. I did not have much to work with. with EBL and Tuner Pro I discovered expanded tables and more tables to fine tune AE. so much better. I discovered my AE was RPM sensitive. I was able to add AE at the lean(WB shows lean + audible pop) at one specific RPM. That worked well. Just added a visable gauge on the pillar column. Now I can see a lean condition in AE as it happens and B4 I needed to look at the logs and locate it. As far as where to DO the change maybe that comes with experience. A small change of TPS will be evident in logs. One can run down a level road at 20 MPH and do a series of tip in each one greater in TPS% and it appears in logs and should be smooth SOP. Issues are that AE quantity can vary based upon many variables such as manifold design and its temp, out side air temp, MPH at AE event, load on engine(MAP), RPM, transmission in use( me a manual)and TPS% change over set time. Look at stock GM table(s). I tried to work off that with global changes. That did not quite work. Past week I added AE at the lower TPS%s and pulled some on the % above 25. I also added AE MAP globally about 10% as on a slow gradual TPS increase from say 10% to 75% I saw the MAP increase signficantly and gauge went to 20/1 amd lean bog(heat soaked again). I added VAFPR so had to redo all two weeks ago!
Reducing SA due to some spark knock retard, my table ended in a mess.
I started over with the EBL_F_0016.bin (stock federal 89-92 tbi tg)with the appropriat FP settings and Hiwy mode desactivated, it runs incredibly nice.
Did some VE learns and lowered SA in the 95-100kpa/4000rpm-up area, were I had 1-3° knock retard.
Also installed a 3wire heated 02 sensor, since I had to stomp it so much to wake the stock one.
Ok, im preparing to bump FP to 20psi if the new spring will allow it.
Is this right?
55 * sqrt(20/13) = 68,219 #/hr
55/68.219 = 0.81
I also read somewere Hiwy mode must be off by VE learning, is this still the case?
Your fuel calc looks good.
For VE Learns, the highway mode doesn't have to be off. It will stop learning whenever it is active. So you get better coverage with hiway mode disabled. I usually set the min MPH to 254 to disable it.
The CCP line to the TB should be pulled and the TB capped.
The EGR should be disabled in the calibration. Can do this by setting the enable temperature high.
Then once VE Learning is completed, re-enable the EGR and tune that in.
CCP can then be re-connected, no tuning required.
There is a section in the WhatsUp.html doc on setting up VE Learns.
EGR is easy to tune in. Enable it and do some VE Learns. However, do not use the new BIN. Just look at the corrections and change the "EGR - BPC Multiplier vs VAC" table for the least amount of corrections. It won't be perfect as the EGR flow moves around.
You can then play with the "EGR - SA added" value. Want to get the lost power back, but not so much that the engine doesn't like it. Be reasonable with the amount of SA added when EGR is active.
Im lost. Could you please make me an exemple on how "EGR - BPC Multiplier vs VAC" multiplier needs to be increased or lowered comparing these 2 VE tables?
When at the VE Learn display click the radio button for 'Corectns' (short for Corrections). At the top of the display it will state 'Corrections in Percent.'
From that you can see the percent of correction at various points. Use the baro pressure and the MAP (from the display) to see the vacuum that needs to be changed for an active EGR.
For baro can key-on, engine-off. It will be whatever the MAP KPa reading is. Best to use the Diag display for this reading. The other place is to do a Dump Log from the analysis display. It is the column labeled 'BRO'.
I set fueling in the copy of stock federal bin and dit 4 VE learns.
Based on the VE corrections, wery similar to te one attached abowe I did the following
and adjusted "EGR - BPC Multiplier vs VAC", in the "EBL-f-ts-0018" bin I already made 3hours of VE learn.
Is this the right way? Im really sorry but this is the most unclear thing for me untill now.
BLM goes rather over 128 then under, also get some single knock retard under medium accelleration in 1 of 4 acclerations and I noticed that even thought the engine is hot the closed loop flag turns off many times.
-I though of reducing "closed loop-02window timeout" from 20 to 10 seconds to stay in more in closed loop.
The weather was really cool and rainy today vs the wery hot day I did the 3h VE learn.
-Since my air intake is drowing cooler air then stock and themperature does dropp relatively fast as speed increases I thought of reducing "IAT/CTS-blend filter of 1/4 and see how it reacts.
Changes seem to be OK, nothing major which I would expect. The slight knock retard with the hotter weather is also normal. These engines are so knock sensitive that reducing the timing to eliminate it also kills the power and mileage (kilometer-age?).
For dropping out of closed loop, best to check why it is doing it first. It may be from open loop decel or highway mode. If it is from limited O2 swing those values can be changed a little.
havent realized tose 3 buttons
