ok well i noticed from this log that it entered PE this time, as the int/blm were locked at 128. With the modification to AE table, it pulled less timing when i went WOT, which was cool. it looks like i still have some work to do, but heres the log!

 

Yeah you can possibly try that but once you get down to 100% TPS it should add all the PE mode fuel you have in that table which 35% is alot and I think it may go overly rich on you. Only reason i say this is I have helped tune 2 cars recently running arap, ones a modded siamesed TPI 383 and ones a 360 HSR setup with decent sized cams and the 383 barely adds any fuel in PE vs rpm while having only minor changes to the MAF tables, and the 360 actually pulls a touch fuel out in PE vs RPM with stock MAF tables.


I'll look at the log again but basically you have too much load in the motor at half throttle and 3200-4600 rpms and the air fuel is way too lean. Its still trying to target mid 14's to 1 from the looks of it, and making sure that PE mode comes in earlier with say 40% TPS instead of 70%, you will get that air fuel where it needs to be, somewhere in the mid lower 13's to 1. As you get full throttle and even more LV8, you will want to see mid high 12's to 1 air fuel most of the time for max power.

Timing looks good, just way too lean at the moment.

So verify you can get WOT with the gas pedal and nothing is in the way (carpet/padding/etc) and lower that TPS % to enable PE and give it another shot. It shouldnt pull timing in the mid 3000 rpm range with PE mode enabled at 40-50% throttle. If your table has 35% PE enrichment adder, you are gonna likely run rich and it may not feel peppy. This is where you need wideband or watch for black exhaust soot/check plugs and also watch narrowband o2. If you can get another log at a true 4.5 volts + TPS and PE mode is enabled, i'll show you what I am looking at to determine air fuel.

 

ok i see. Yea I might be able to adjust the TPS a bit to keep the ~0.55 idle and near 4.5 for WOT, ill definitely lower the TPS% to enable PE mode then. I actually did like you said and lowered the PE fueling % since my first logs weren't actually WOT to begin with, so thats only around ~18 instead of the 35% like before. I'll have a wideband o2 within the coming week since ill be back at purdue and can use my friend's lol. then ill take a look!

 

The log you last posted looks better and is starting to resemble what i was expecting to see. It appears WOT or 75% throttle to somewhere around 90-95% throttle is rich enough to be save. O2 milivolts appear to hang around 914-932 mv between 3800-5000 rpm. Slightly richer than optimal but verify that with wideband and dyno testing. You probably can take out around 5-6% PE between 3800 and 4600 or so rpm. take out 3% above 4800 right now til around 5200 until you take it higher than that in your logs.

Still pulling timing which is strange. 33-34 isnt much but maybe you have high compression and a somewhat milder cam? What octane fuel you using? Any exhaust hit the frame? Around 3800 rpm, LV8 between 192 and 208, i'd maybe back off timing from 33 to 28-29 and see what happens. Bring peak timing of 34 down to 32 and see what happens in the next log. If it still pulls the same timing it may be false knock.

PE fuel curve will need smoothed out. Definately enable it at 45-50% TPS. Still too lean for those higher rpms and half throttle.

Another thing is I like to keep injector constant set to actual injector flow rate for the fuel pressure you run. Then tune the MAF tables to hit your 128/128 blm/int values.

I'm kind surprised the peak LV8 on this motor was 240 so far around 4000 rpm which will be about where max torque is coming in, and max g/s MAF flow is only around 226 so far. I'd expect to max that out. Possibly will happen once you pull to 5800-6000 rpm or so and have fuel/timing dialed in.

 

once again Orr, i am in your debt! thank you so much for the information and suggestions. I will definitely get to changing those values and doing more logs, hopefully in the upcoming week when i have the wb02. I'm also surprised at how the maf isnt maxing out.

Regarding your questions, when i measured everything up for compression ratio before i threw on the AFR195s, my final figure came out to about ~10.13:1 or so. My cam is the XFI268, which we installed without advance or retard. I've also got the factory TPI so my pulls are restricted to that airflow. Regarding the exhaust, driver side header is pretty close to the frame, so its possible that there is some noise there.

 

For some reason I thought you had a different intake setup. Stock TPI would explain the lack of air flow. Needs opened up and you'll see big gains

 

Yea, i think an HSR or another style intake is in the works for the near future...i hope to get something this summer.

 

Ok I made some changes per your advice last time, and here is my datalog. When it enters PE mode I'm still getting timing pulled as i mash the accelerator, but it also occurs under small loads of acceleration, so I'm going to increase the low end of the change in LV8 vs AE table to try and combat those.

I did hook up my club's wideband LM-1(i know its old) and had my friend watch the controller at WOT, when PE mode was engaged. I'm pretty consistently around 11.6:1 there. So I might actually pull some PE% enrich out to get near ~12.7:1 like you mentioned.

As we are cruising, the WB02 is sort of all over the place, probably because I've barely changed the MAF tables yet, but you're correct that while cruising it gets very lean, around 17-18:1 on occasion according to the wideband. This could probably be causing my random knock retard during cruise as well, which i was wondering about.

I was also wondering about the narrow vs wideband placement. Currently my narrow band is only one bank, driverside, at the bottom of the headers. My wideband bung is actually AFTER the collector, so it's reading both header's worth of exhaust, which should be more accurate correct? I ask because according to the narrow band, I might be around 118 BLM, which is rich, but the WB02 reads almost right on Stoich 14.7:1 and the engine sounds great.....so should i trust the WB02 over the narrowband most of the time?

Thanks!

EDIT: Also now with the wideband i was able to see that on startup, in open loop, the engine is very lean...so i should enrich on startup correct?

 

I'll look at that later tonight but quick response on the other items:

If your reading the average of all 8 cylinders then you get the average of all cylinders, meaning you will not beable to tell if one bank is lean and another is rich. Most of the time both banks are close to the same anyway, but since not all 8 cylinders run the same air fuel anyway, its ok to measure average.

Only thing to watch is that you have good connection with the ypipe and collectors so no air leaks. Air in the exhaust will skew the reading.

118blm is abit rich but not terrible as long as the INT is also close. Give the motor what it likes and go from there. A MINOR change to MAF tables will bring that in the mid 120s and I'd leave it there. So you are not far off.

Open loop, you can try disable closed loop in the bin for now and just work on open loop with the tables. Open loop vs coolant temp and open loop vs lv8 i think. That will help get your cold startup stuff in line. If thats tuned well, the ecm wont have to make changes in closed loop

 

Found a few areas where you can make some changes. Some deal with MAF tables but I'll get to that later.

Right now the narrow band indicates rich on PE mode when over half throttle to near wide open throttle. If wideband confirms i see no reason why you should have as much as 7-8 deg timing pulled by the knock sensor. It shouldnt pull timing there. It could be one of 2 things. False knock, or maybe the base timing doesnt match actual base timing. Could be a bad timing mark or balancer slip where you have more timing than you think you have. Doesnt make sense to me that its pulling when being on the rich side of things.

If you cant rule it out as false knock then you will have to look into running less timing and see where that gets you. What octane gas you using and are you sure your compression is pump gas compatible with that cam?
I dont want to recommend changes if the timing being pulled is false.

 

^^ hmmm. i set base timing to 8deg on the balancer and made sure to set that in the bin as well. I could take a look at that again. im running 93 octane gas and i have a friend with a very similar cam and head setup running 34* timing and he doesn't get any knock. It could definitely be false knock, as my driver side header is very close to some things in the bay. Also, I've read that throughout the late 80s to early 90s, GM switched the models of knock sensors a few times and they don't have the same ohm resistance or voltage apparently? Do you know if this might affect my readings?

Since the wideband confirmed 11.6:1 in PE i agree that it's weird that its pulling timing. As far as mashing on the throttle and it pulling, i might be able to fidle with AE still a bit more and see where that gets me, it looks like it corrects the knock in a bit of time after i mash WOT.

I think I'm going to start with backing off timing on the spark table like you mentioned and see if that yields the same results.

 

Yeah try pulling a good bit of timing up there and see if it repeats. If it does then it has to be false.

Verify you have the correct knock sensor for the motor/system you are running. Running a 305 sensor in a 350 can have inaccurate results in detecting knock and it may pull timing when there is no reason to pull timing

 

i had written down information regarding knock sensors somewhere, i can't
believe i forgot about that. I think i'm running an '86 305 sensor from the 305 that was horribly swapped into my car when i bought it...and i swapped that over to the LO5 350 block i got, which is a '92. Since i have an '86 ECM, I'm going to try and pick up an 86-89 350 Knock sensor as well!

EDIT: should i get a 350 ESC module while im at it? i don't believe that was ever swapped when i went from 305 to 350, just reading about it now. Sorry for the newb mistakes, i can't believe i made them lol. Altho supposedly some people say the 305 ESC still works with this configuration https://www.thirdgen.org/forums/post...784-post2.html