Quote: Originally Posted by pandin It is not a perfect world we deal with. I am quickly learning and slowly dealing with it!!

I would like more explanation into this. I ditched my previous work, and took arap and modified it. I am getting spark knock so at the point the spark knock shows up, I need to work on all the areas before this?

Knock retard can be invoked at many sets of conditions, what happens is as the mixture quits burning and starts exploding, it creates ping and then detonation. The amount of depends how much fuel/air is unburnt, when it pops. When the exploding starts, the heat rises fast in the combustion chamber, this extra heat allows the next cycle to pop sooner and with more unburnt fuel. Get it hot enough and you could run diesel fuel (with out a spark).

I got the most spark retard at WOT and 55 mph tip in's (like poking the cruise control button to raise the speed one mph).

Read the attachments and see what you still have questions on.

Very good information. I have read through entirely once, and will need to read through a few more times.

So what I have done is taken ARAP, and changed a few constants. I took the spark advance table, and subtracted 10 degrees from the whole table. I also adjusted my max air flow vs. rpm table. The car runs very good. Good throttle response and more power than before. I am still getting spark knock.

Spark knock is showing up before WOT. I am looking at the LM1 file, and notice that I am 15:1 or so AFR before the wide open throttle transition. So I think this is the root cause.

I don't necessarily want to take timing out if there is another cause. Any suggestions on taking care of this?

I'm a little out of my element in 6E in that I can't use the BPW table vs load. So I have gone back to the stickies to try to determine what actually needs to be done.

A 15:1 AFR at pre wot is normal, that is where I run. I am leaving for work, so will give you some more insight tomorrow in the am.

Ok, sounds great. Thanks for helping me out with this. Thanks to everyone that has contributed to this post, and all the posts I have read.

If the spark knock is occurring before WOT, then I have work to do before that condition occurs. Maybe I will work on exporting some numbers from my LM1 file.

I uploaded a pdf of the log

Send me that last run as a xxxxxxxxxx.uni.txt file, I want to look at more of the run.

Would that be the datamaster file, or log file from my LM-1. Whichever it is, i can get that to you. I am at work now, so it wouldn't be until this evening. I'm gonna have to start bringing my tuning stuff to work!!

The data master file is the .uni

The extra fuel is added by the PE tables, there are other settings to say when to add it.

When you send the uni file, I will plot it in an excel sheet. This will give me a better big picture, about fuel and spark.

I have seen a hint of some minor issues but want to be sure about my suggestions.

Here it is!

First off, test your TPS, it seems to have a dip in volts (4.5 to 3.57) at record #6754, but not during the previous 3 stomps. Knock retard is also 10 degrees, at 3200 rpm rec 6747.

Read the attached doc, it was copied from tgo, and is responses from various members. It is not my work.

read Grumpy's Sparks- The Final Answer.

Well I feel like I am understanding more, but now feel more confused than every. After looking at my SA curve, I see that at 3200 RPMS SA is 13 degrees, and at 4800 is 25. This doesn't seem correct from some of the things I am reading.

Now, one of the things I do not understand is why the spark knock is occurring so early.

I'm reading the section about dialing in a spark advance curve. It starts out by stating that start with low values. Increase the SA 1 degree over 3200 RPM's. Until detonation occurs. Mine is all well before that RPM.

The number has to do with your heads, cam, cr, fuel, and quish.

Fast burn heads, no egr, 87 octane, and hot plugs need a lot less.

I would try Aujm or Apyp main spark tables and see if your knock is gone, if it is then tune up from there.

I will give that a shot. I really would like to get this thing to where it isn't pulling any timing, then just keep tweaking on it.

I think the hang up point for me is that at 3k or so, the computer is pulling more timing than is advanced anyways.

I think I understand, from the readings but I am not 100% clear. My base timing is set at 6, and that is what I have set it in the bin. The spark advance I see, does that include the 6, or do I need to add the 6. Somewhere along the lines, I have seen spark advance total, and then spark advance relative to base. I can't remember where I read that. It might have actually been in software at one point.

I also understand the fact that there are other things at play that advance timing as well.

For both of those, do I use the 6E mask in tuner pro?

Just copy the whole table and paste to the Arap table.

Ok, so I copied the table over. I did not notice much difference between the AUJM table and the ARAP table that I modified. All I did was was subtract 10 degrees across the whole table.

I took the car out, and from the first pull, the car was much slower.

Running with AUJM, spark retard wasn't as severe, but it did occur in the same spots. It appears I have much to do.

What is the main cause for the car being so sluggish? I have attached the uni file for anyones review.

When you changed spark tables to Aujm, it lowered all the spark, that is why it was sluggish.

You need to pick a table (Arap or Aujm), lower the spark at the retarded spots and raise it where there is no retard. The reason to lower the spark at retard is you are pre retarding in the program, as opposed to post retarding by the knock sensor.

This is also called calibrating the spark advance curve to the engine (your engine).
Because every engine is different, the best curve is different for every engine.

That makes sense. I think AUJM spark curve is the closest starting point, and I will adjust from there.

I plotted your last 2 uni files in an excel spread sheet, I agree.

I noticed that your load is maxing at wot, I would lower the scale factor at LC05B0 down from 1.25, don't go lower then 1. This is a multiplier that raises your load value, I run mine so at the max load rpm, it reads 255, this brings the load back into the range of the ECM. Running out of your normal range is called clipping, instead of nice round humps, you get flat top mountains.

My view is that if you are running out side of the reading range, then you are losing information. This scale factor is what calibrates your load output to the ECM. A lot of Maf's read low (305's) so they used this to boost the value to the top of the range. If you have a 383 then you need to lower this, to bring the value back to what the ECM can read. It is the load that sets the spark curve, so this needs done first. Once you are just touching the 255 limit at the highest load then move on to the spark tables. It will make a bigger difference in the part throttle then the WOT.

The only time you need to look at this is when you change the maf or CID.
A 305 will need the 25% load boost, a 383 won't.

I lowered mine to 1.17

What do you recommend for a good hex editor? I am assuming this is the only way to adjust the value (LC05B0). I'm gonna poke around on break and see what everyone else is using.

Also, on the last run, the wide band measured 16.5:1 breifly after the TPS was already at 4.5 volts. So I think I may need to play with AE?

I use TunerPro RT everything you need is there to change the bin numbers. Just use the right XDF file that has what you want to change listed, or you can add the location to your own XDF file.

You can also data log from tunerPro either will work for me.

Also when you do the next data log include at least one WOT from a dead stop (5 sec), up to the top of second gear. Mash your foot on the floor hard, tight, and let the car do it's thing. Don't let up until after the shift, it will put you in ticket MPH range so pick your spot carefully.

Now were talking!!! If I do get stopped, at least I will have an excuse!

I am going to download TunerPro RT this evening when I get home from work.

I will try to get that datalog in tonight as well, after I change the variable.

try this

That looks different, I did find the load scaler. Anything else I should change other than the norm, injector size, spark table, etc.

Lets get a data log with the lowered spark advance, after the retarding is fixed. then see where you are at.

Was the first uni file one that was peppy or a dog. The second one was the aujm one, the first had 10* removed from arap, right?

The most recent was the AUJM spark table.

I'm going through everything trying to tie any loose ends. The maf tables have my attention. The max reading my maf returns is 4.50 volts. This occurs at around 3700 rpm's. So i'm wondering if I should set the max air flow at that voltage in the tables and work back from there.

Record #8680 is right before the two full gear pull. It is a pretty long tune. The car seemed to run better. This is nothing more than the AUJM spark table, with changed load scaler.

The airflow in your tables should be correct, assuming a good sensor. I think your 4.5v cap is a prob with the sensor, spray it with some maf cleaner. Sorting out a lean spike when you smack the pedal is harder with maf than map because there's no real time vac measuement, only estimated (LV8). With my peaky 'lil v6 I see the wb flash to 17:1 before accel enrich or p.e. kick in, and I really haven't been able to nail it down. A few things you can do that will help are lower the qualifiers as much as you can without triggering them from normal pedal tweaks, adjusting the accel enrich tables- %BPW vs refrence pulse in particular and a biggie that most people overlook is signal filtering- gm programs enough filtering for a clean smooth signal, but it also causes a bit of a transient delay that when stacked up with accel qualifiers delay and the delay within the sensor (or calculation in the case of LV8) can be quite large when dealing with an event that happens in miliseconds.

To whoever mentioned that their wot afr wandered- this is a result of port wetting. I've noticed it in my datalogs, as rpm's increase it gradually leans out as fuel sticks to the port walls until it shifts and richens from extra fuel being pulled off the port walls, then gradually leans out again. Just use the PE % change vs RPM table to add the needed fuel.

In my WOT runs, I have noticed it get richer, than when the RPM's change the AFR changes with it leans out, than starts gradually getting richer again.

That is where I would and do run my load, It tops out at during the shift.

Are you running a 3500 rpm stall converter?

Your knock retard peaks at 3700 rpm and is 14 degrees, your SA is at 20. The knock starts at 3200 rpm and fades at 5000 rpm. Usually the knock retard is heavier in sec and third gear (more load).

I would remove 10 degrees of timing at 208 load from 3200 rpm up to 4800 rpm. Then do a first gear pull and into sec gear (70 mph) to see how much has changed, there is knock retard at 4200 rpm in sec gear, this could also be banging pipes. Check out by shaking the exhaust and listening for clunks.

I have a 2400 rpm stall torque converter.

That sounds reasonable. I will do that. I'll try to do something this evening if the storms hold off. Right now it has been one right after another.

What in particular are you looking at when trying to identify my torque converter?

I was looking at what rpm you are turning, when the mph starts to go up.

Rec 8686 is when the TPS starts to rise, rec 8694 is when the MPH starts up.

Rec 8693 MPH is 1 and RPM is 2693.

Rec 8698 MPH is 24 and RPM is 3523, this holds till rec 8709 when MPH is 29 and RPM is 3766. You pass through 11 REC's and stll hold at 28 mph but RPM goes from 3523 to 3766. This is a lot of lost motion and is not wheel spin, cause wheel spin would raise the MPH. This is where you get all the spark knock. Tranny slipping?

The next 11 Rec's bring you to 44 MPH and 4842 RPM (rec 8720). See what I mean.

Mine rolls at 2000 rpm, this is by direct observation, a stock vette TC stalls at 2000 rpm.

I guess I never really noticed this. I don't think the tranny is slipping.

How does the car determine mph? Look at rec #8694 mph 5. Then rec # 8695 mph is 18.

Now i'm not sure what is going on with speed. Then later as you state the car basically stands still, but I notice no dead spots where the car stops pulling.

Your speed is calculated from the pulse coder located at the output of the tranny, unit installs in hole where speed-o cable was attached.

Info is sent to the ECM and the dash.

I looked at the adjustment of my TV cable, and tried to re adjust it for good measure. I think it is stretched. When I pushed the sleeve back into the bracket (Towards firewall), then opened the throttle up, the piece did not re adjust itself, no clicking of any kind.

Now to my question. What in the code makes the car shift differently. When I was running the older bin with the 32 xdf, the car shifted differently. The most noticeable is second to third. With the new 6E bin, 2nd to third is sooner, and the car slips into the shift. This is under light acceleration.

Spark knock is almost gone.

I would have never removed SA from that load range. I thought we discussed before that spark knock builds and occurs before it happens?