antman89iroc

How much duration/overlap have you been able to tune well for a street car run at street RPM ranges?

I'm finally back in closed loop- well sort of...

You can check my sig but my cam I would consider mid-to-upper range for my motor size. 236/242 on 112 in a 414CI motor. I believe should work with closed loop. Overlap is 70' I believe.

The EBL's ability to stay in open loop for idle made closed loop an option for cruise only so that's what I did. I have CL coming in at almost full temp @ 75'c just to not worry about the transitional issues for now. I have dummed down some of my prop gains and worked on the O2 R/L cross points/limits. It's working pretty well and as I get it down I may broaden the closed loop range and hopefully get to idle as well.

One of the issues that seems to be causing part of my problem is the fact that a lot of the operation is in the 18-2200PRM range. I believe this is where my cam doesn't work well. Probably still quite a bit of reverstion/self EGRing, especially in the low load ranges, it seems more stable in the mid and higher load. Also contributing is the HSR intake seems to run lean up front and rich in the back, especially in the cruise RPM. Plug readings show the same. So it may be impossible to keep all the cylinders "happy" at the same time.

Although it seems to be fairly stable one of the main challenges is the variations in reported WB fuel ratio. At low load (35 map) it runs richer and at higher load (45-55 map) it seems to go leaner and seems to stabilize around 15.5-16AFR even though the o2 tables are 600+ in these load ranges. Stock O2 tables are closer to 450. And when I say fairly stable the WB meter is pretty much all over the place. It constantly hovers around a certain AFR range but has high and low spikes and is moving all the time. I have been considering this "normal" even though it doesn't seem right. I've been trying to focus on how it runs and BLM stability across various ranges rather than specific AFR values.

I have been reading and re-reading Bob's PID paper and it helps a lot. I've also been looking at some of the FAQ documents. If anyone has any tips please chime in. Especially for the EBL Flash ECM.

34blazer

Are you trying to pass smog or something?

Orr89RocZ

iTrader: (20)

I ran 78 on a maf system on my hsr 383. Ran well. I had a closed loop initial startup issue where i think it tried to go into closed loop sooner than when the o2 sensor was ready. Ran lean for 20-30 seconds everytime til it warmed up but after that it evened out.

I went to open loop anyway as i couldnt figure out that issue was but now i think it had something to do with o2 ready timers

antman89iroc

No, just trying to get it to be stable. Have been running open up to now. I don't really care but when running open EVERYTHING has to be perfect to compensate for changing ambient and other conditions. Closed loop makes those little adjustments. I'm just trying to get it close. Plus it's a challenge.

The odd issue is at times the computer will pull fuel when it's already lean, or vise versa. Or it will compensate in the right direction but go too far. The other strange thing is even though the O2 r/l tables are over 600, WB still reports ~16 AFR. It's difficult to know what to believe. That's why I'm trying to go by "how" it runs rather than hitting a mark.

34blazer

my old mustang was using a 7730/S_AUJP and the engine had a fully ported head/intake combo with an E303 cam. Had a decent amount of overlap but the alphabet cams have a lazy lobe. I tuned for closed loop since it needed to pass E check for Ohio at the time. Was going to use OL but, like you, I wanted CL to make changes for ambient temps. If you don't need to have it smogged, you can tighten up the 02 rich/lean tables, to try to get the ECM to swing the AFRs less. The main reason why it swings the AFRs so far is to average 14.7, since there usually is a CC on the exhaust that needs to digest air and fuel just like the engine. When you tighten up the R/L limits, that helps lessen surging on the lean part of the swing. It helped my old 5.0 a lot. The 02 "mean" table can be adjusted to target your stoich AFR, or what the engine determines is its happy place. Just keep in mind that when you adjust one part of this table, the rest of the cells will need to be adjusted otherwise you will start to see goofy AFRs when transitioning from different RPM ranges. Also, there are scalers that are used to determine AFR "swing" vectors, or speed and direction, that will need to be adjusted once you tighten up the R/L tables. Those scalers will also determine if the AFRs are swinging far enough, if that condition isn't met, the ECM will transition to OL. I had that problem when I first tightened up the R/L tables, it wouldn't stay in CL until I found those scalers and tightened them up too.


Also, if you don't have one already, install a heated O2 sensor, otherwise you will have issues with a non-heated unit cooling off too much and ECM trying to over compensate by adding a bunch of fuel, or pulling a bunch of fuel. If not using a CC and longtube headers, or larger primary shorties, then the non-heated O2 sensor will not be heated enough, most likely.


HTH

Ronny

iTrader: (1)

[QUOTEAlthough it seems to be fairly stable one of the main challenges is the variations in reported WB fuel ratio][/QUOTE]

You may want to try to slow down the reporting of the actual A/F by the WB. There may be a setting for that. When I added the A/F pillar gauge I noticed it changing constantly. My Innovate allows it to average the changes so as to not make you dizzy watching the parade of changing numbers.

Dominic Sorresso

I've tuned my L83 Xfire and now my LT-5, both cammed motors and used the same approach for both. The XFIRE had a full roller setup in it. Cam not as large as yours BUT it was a stock displacement. It was a single pattern roller cam and had a tighter LSA, 108*. Spec was 218@.050/.535" w 1.6 ratio SS roller rockers.
Heads were TFS 23* 64cc chambers 2.02 valves.
I read a lot of Traxion's stuff here, and lowered the idle O2 settings to address the false lean because of the overlap. Really did not need to modify O2 windows anywhere else. Prop gains were also lowered.
The cams on the LT-5 are more "modest" due to the 4valves. Again, played w O2 idle window although I learned that going too low (<.2v) would set a lean code because ECM was doing what I told it to do. Surprisingly tho, I went back to the stock Prop Gains after using RBob's rule of thumb of listening for a "bad u-joint". Now I've been able to dial in the IAT table and finally have gotten realistic numbers for the Injector Bias v BATT V to smooth things out further.
Also adjusted AFR for the 10% Ethanol, so cal is calling for ~ 14.2:1. My WB readout doesn't allow for a different curve, so I just look at Lambda instead.
Also adjusted the RPM and MAP param windows for where the motor operates L/M/H.
Sometimes I shake my head when somebody asks "for just a tune", but then that's how I started out.