All O2 sensors created equal?

[JeepsAndGuns]

I knew there would be some comments about my timing....lol Base timing is set at 10*, this is entered into the bin. This engine is NOT a chevy engine! The cyl head and combustion chamber is different than a chevy and the timing curve is going to be very different. AMC engines are generally known for liking more timing. I have also had the heads shaved a bit and run 93 octane gas. When setting the timing it would barely idle at 0*, let alone drive at that, so base timing is set to 10* so it would still be driveable should I ever hit LHM. As for the table/advance, I simply gave the engine what it wanted. The spark curve for a AMC engine is so different from a chevy, when I tried running a stock chevy timing table, it was pretty much not driveable it ran so bad. I spent endless hours on the weekends emulating and carefully making this spark table. Advance at steady cruise was based off its manners. If running lower than what I have now, it would have a pop/miss to it at steady cruise, I started removing and it got worse, I then added and it went away. Same reason I had to reduice timing at the very high map areas. When doing a steady cruise at parking lot speeds (high map) it would pop/miss. I tried the same as above, and found I had to reduce timing to make it go away. Idle timing was also set at while emulating. I adjusted idle timing to acheve the best medium between idle smoothness/quality and max vaccume.

I did not notice the vss spike, I will have to go and watch for it. What could cause that?

You finally see what I'm talking about, afr is all over the place! I have the DFCO set for personal prefrence, as when I let off the gas, I want it to slow down, and I love it. It may slightly bump it when shifting gears, but you can not notice that it does, and shifts are great. But even that shouldnt make it have screwy afr all the time, I could understand maybe a second or two after a shift/defo cycle, but not all the time. Heck, since I have installed a mtx-l on my YJ, I have noticed its stock fi system will go dfco instantly when I let off the gas, and hit it between gears, but it makes barely anny effect on afr except for about a second or two.

[EagleMark]

OK, but if you did a log that way I could have ruled out the misfire/ping/detonation... before each shift for sure, not sure about the others...

And if you want to get those AFR closer you'll need AE settings for a manual... Very rarely do you get AE in between gear change and INT is trying to correct taking your WB and desired AFR with it. These are 4.3 but 7.4 may be differant?
Map Difference to Enable AE down to 10 -13kpa from 16
TPS Threshold to Double MAP AE to 3.5 % from 30%
TPS Threshold to Double Delta MAP AE to 30% from 79%

Here's steady state driving.


Here's inbetween gears.

[dave w]

I had a few minutes at lunch, so I looked at the AE / PE for the log on 1-27. I did not see PE active. The attached file (excel) is a filtered view when AE was active. The screen shot is a from the excel spreadsheet. Depending on the location of the WBO2 sensor, there is a slight delay in the WBO2 reading and when AE is actually active. I think the AE could be a touch lean?

dave w

[EagleMark]

I'm not sure if AE is lean... but as your spreadsheet proves it's hardly even on! That picture above of monitor going threw 3 gears AE never came on...

[JeepsAndGuns]

How often should AE come on? I thought AE was only supposed to come on when you hit the gas somewhat hard. I tried to drive somewhat normally and not punch the gas too much and accelerate normally making sure to stay out of PE too. AE is one thing I have not touched on this bin, mainly because there are just SO many AE parameters I wouldnt even know where to start. Not to mention there being two AE's (tps & map) makes it even more confusing on where to start. Though, I do think it may need a little tweeking as if driving steady and then punching it, I can see the WB go lean just a sec then be fine. What exact parameters are you refrencing above? Do you have the addresses and a reccomendation of what to change them to.

If yall want, I can give you a log of my normal driving style with this thing (aka, a bat out of hell...lol) Punching the gas, some wot runs and punching it from a steady cruise.

Also forgot, I am running bosch 0280155931 (LS6?) injectors. Rated at 258cc/min at 3 bar. I am running 45 psi of pressure and calculated aprox 25 lbs/hr. I am also running a vac refrenced fpr.

[EagleMark]

Those were the exact parameters.

Map Difference to Enable AE down to 10 -13kpa from 16
TPS Threshold to Double MAP AE to 3.5 % from 30%
TPS Threshold to Double Delta MAP AE to 30% from 79%

Should also compare a manual bin and look at Decel Enlean and DFCO. Or just turn them off till you get AE figured out. They really throw everything off and take a while to stabilize.

I really wish you would at least turn off Decel and DfCO (adjust AE too) and take 5 degees out of the entire table and do a log!!! Those V shaped downward spikes in your WBO2 readings looks like a misfie/ping/detonation... it's even messing up your commanded AFR. I can find nothing fuel related to coincede? The VSS spikes don't coincide? It looks like a miss...

[dave w]

I make the following analogy, AE is like a carburetor pump and PE is like the secondaries opening on a 4 barrel carburetor. In the case of AE for EFI, an extra squirt of fuel is needed when the throttle is quickly opened, to allow time for the MAP sensor to react to the change in value. Once the MAP sensor recovers, the ECM will correct the fuel with the BLM. I usually target the AE AFR to about 12.5 +/- 0.5 AFR. The spreadsheet I attached showed the MAP and TPS, so as a starting point I would add about 10% ~ 30% more in both the AE TPS / MAP tables and see what happens to the AFR's when AE is active. Same method applies to PE. I quite often lower the TPS needed for PE by 20% ~ 30%. I quite often lower the PE AFR from 0.5 AFR ~ 1.5 AFR. The data log / excel spreadsheet is very useful with the WBO2 data!!!!!!!!!!

dave w

[RobertISaar]

actually.... the MAP sensor is quite fast... it can update accurately at a rate of just over 160Hz. the fastest logic i've seen involving it runs at 80Hz, so by the time it updates, it's accurate.

the need for AE fuel comes from the rapid pressure change causing the fuel to basically stick onto the port walls instead of going into the combustion chamber. the air always makes it in, so without correction via AE, you would run lean until the fuel quits having that tendancy to stay in the intake or head ports. direct injection doesn't have this issue, but port FI does. TBI and carb get it the worst though since they have the longest path from the injector to the head of the intake valve, so more places for fuel to get stuck to.

[EagleMark]

I agree with you guys... but the point is he has no AE at all in the three gear changes in this picture.

Blue line on bottom is TPS% 25.5

Pink link is WBO2 AFR 13.4

Orange line is MAP 67.6

Green line is INT 129 and it's going nuts trying to fuel that TPS movement with no AE... look what the WB is doing?

[JeepsAndGuns]

So what your saying is AE should be coming on when I shift gears and its not?
I could see that screwing with things during gear changes, but the afr will vary (usally) between 13.5-14 during a steady cruise.
I will do some compareing when I get home from work this afternoon. I will check out a 4.3 manual bin and open two instances and compare it to a 7.4 manual bin too.

[EagleMark]

So what your saying is AE should be coming on when I shift gears and its not?

Right.

but the afr will vary (usally) between 13.5-14 during a steady cruise.

Right, see the V shaped downward spikes in pink WBO2 sensor line? Looks like a missfire/ping/detonation, it's worse under load. Take out 5 degrees spark across the table and re log! If I didn't see your spark table I would say pull plugs and inspect which you should do at this point as well...

[devind]

I make the following analogy, AE is like a carburetor pump and PE is like the secondaries opening on a 4 barrel carburetor. In the case of AE for EFI, an extra squirt of fuel is needed when the throttle is quickly opened, to allow time for the MAP sensor to react to the change in value. Once the MAP sensor recovers, the ECM will correct the fuel with the BLM. I usually target the AE AFR to about 12.5 +/- 0.5 AFR. The spreadsheet I attached showed the MAP and TPS, so as a starting point I would add about 10% ~ 30% more in both the AE TPS / MAP tables and see what happens to the AFR's when AE is active. Same method applies to PE. I quite often lower the TPS needed for PE by 20% ~ 30%. I quite often lower the PE AFR from 0.5 AFR ~ 1.5 AFR. The data log / excel spreadsheet is very useful with the WBO2 data!!!!!!!!!!

dave w

Dave you should make a list of different analogies comparing EFI and carb terminology and post them as a sticky thread, because every time I read one of your analogies another light bulb lights up in my head.

[PJG1173]

I agree with you guys... but the point is he has no AE at all in the three gear changes in this picture.

Blue line on bottom is TPS% 25.5

Pink link is WBO2 AFR 13.4

Orange line is MAP 67.6

Green line is INT 129 and it's going nuts trying to fuel that TPS movement with no AE... look what the WB is doing?

wow I just learned how to do something new with TP. cool I never realized it could do this.

[JeepsAndGuns]

Map Difference to Enable AE down to 10 -13kpa from 16
TPS Threshold to Double MAP AE to 3.5 % from 30%
TPS Threshold to Double Delta MAP AE to 30% from 79%

OK, I looked at those parameters in my bin and they are as follows:

Map Difference to Enable AE 16.3
TPS Threshold to Double MAP AE 99.6
TPS Threshold to Double Delta MAP AE 79.7

I pulled up my old BMHK (0E 7.4 manual bin that I no longer run because of many problems) and looked at it. I remember in it, I never had any problems with the slight lean spike when hitting the gas (AE) It has the following numbers for the same 3 parameters above:

18.1
44.9
14.8

Looking at some of the DFCO and DE parameters, there are differences there too, Some more than others.
What do you think of copying all the AE, DE, and DFCO setting from that bin? Its a 454 manual trans bin.
I will do as requested and remove 5 degrees of timing.

As it seems to always go, it looks like it will be this weekend before I will be able to get time to do another log.

[EagleMark]

Your numbers from your bin don't match what I found?

Definatly do not want to raise Map Difference to Enable AE, want to lower.

Look at a 4.3L Manual in $0D, they seemed to go the right way. Ever since we went out of our way to use that manual $0E bin it has been trouble!