Hey guys I've posted my tables on the Prom board but didn't get much feedback on them so let me know what you guys think about these. These are the tables I've roughed out for my upcoming setup in my sig. Do you think this is a good starting point to get the engine running ok or do I have too much or too little? Give me any suggestions, thanks.

Fuel Graph of VE #1

Spark: (note: the Main Spark Bias is set at 20.04 as in the stock bin)

hmmm... it looks like it should start the engine. Id also suggest moving the desired idle speed up to around 650-700 rpm for starters. On an untuned setup the slow stock idle is a real drag. Once you get it to idle ok around that area you can unplug the IAC and do some low rpm tuning to get it tuned in down there. If you havnt already done so, get a WB-O2. Its an absolute must for doing WOT tuning and getting the pump shot dialed in. W/O it youll be flying blind like me. The stock O2 is jsut about useless and plug cuts are a real pita to do whenever I want to check up on the fueling. Necessary, but it would be nice to jsut ahve a display to look at in addition.

On the timing side of things. The timing at idle looks ok. Make sure you set the base time in the prom to what is at the dist. so the timing you enter in is what the engine actually gets. At WOT it looks like itll bog since its only getting around 20 degrees of advance but you can address that when the engine is finally running.

The only way youll really know how they work is when you get the engine going. Just about every engine is going to want something different.

You have the wrong ecu file. There is an updated version that I have on my laptop. Where did you get that ecu file from?
I'll post the new ecu file up in a little while. DO NOT edit the main VE #1 table with that ecu file, the RPM and MAP are switched and since the table isn't a perfect square it's difficult to visualize.
Your spark tables need some work. From what I see you have a straight line in the 100kpa (WOT) area. This should be a slope to a max around 36 degrees or less. It's probably closer to 30 degrees at 3600rpm at 100kpa but I'm just giving you an idea. Also, look at all of the other tables and the bias vaules. Remember that the bias values and the initial SA are all subtracted from the final SA. A good engine with no restrictions in the exhaust and/or intake (all in the head and cam) would have the most spark advance in the lowest vacuum, highest RPM cell, this shouldn't exceed 44 degrees! Keep in mind the bias values. You might want to set the main SA bias to 0 and just subtrace the bias from your main SA table.
Next step is to set your 100kpa 3600rpm cell to a value between 28 and 32 for iron heads, 30-38 for aluminum. Then disable the sloped SA by setting the degrees added/1000rpm to zero. Then set the idle timing to where it likes it and everything else is a blend. Don't get caught in the trap of looking at knock counts and where they happened with winaldl. The baud rate is so slow that the reported cell might not be correct.
I hope this helps. I'm so busy right now with school and the formula team that I've had no time to give my fellow TBI tuners anything else useful.
Again, I'll reply with the correct ecu file and if I don't, e-mail me. Do a search, I believe I've posted it before with a renamed file extension (images only ).

Another thing. Didnt notice it before but the area around 400 rpm/100 kpa should be around 8-10 degrees, not 20 degrees of net advance. Youll need this to provide a smooth transition from running off the module advance alone to running off the table when the engine finally catches. Youll also want to make sure the 'well' around that area makes a smooth transition to the rest of teh table. When I first started tuning I made the mistake of having it be like a cliff and when I went to start it I got violent detonation adn it wouldnt start. Smooth that area out and have it blend into the rest of the table since the motor will be traversing that area on startup.

Another thing that worked for me at least was to start around the area at idle on the spark curve and work my way out. From there i worked on the low load/rpm spark. Once I got taht roughed in I went on to moderate loads/rpms and worked on that. After that I went to the WOT stuff. One of the advantages in my eyes is that the general shape of the timing curve emerged at each step of the way and I could get an idea of where to go next. Again, this is what I did, and taking small steps at a time really helped to do the P/T timing, which was especially dificult on my engine.

Thanks a lot for the input guys I did all the stuff you said to do here and hopefully that will work out better. That spark table is basically just stolen from the AUJP bin and roughed into the 8746 table. I noticed the reason the 100kpa is a straight line is because the TBI table stops at 3600RPM whereas the TPI table goes up to 4800RPM. It looks like it begins to slope upwards just after 3600RPM in the AUJP table and I didn't account for that.

That was a lot of good info please keep it coming if you have any more ideas! I guess I'll just work on smoothing out this timing curve now; I would like to get this engine running halfway decent when I start it up and not misfiring and running horrible.

Jon, in regards to the ecu file, I remember downloading it from some site that was linked to on here but I can't remember what the site was, sorry. I could be wrong but I thought 25THRSS posted a link. I did a search but couldn't come up with anything. I do have two of your other ecu's on file though so I'm going to use the last one I got for now.

Ok I was bored and went through the spark table again doing what you guys said as well as zeroing out the spark bias's; what do you think of it now?

Graph:

i would still smooth it out quite a bit, smoothing the table make the car much smoother when just cruising around. you basicly want full advance worked in by 3200 rpms, and then just make it a nice slope up to the point, you don't want the advance to go up, and then back down, and then back up.

Like dewey said, smoothing is another good thing. If the curve has humps and bumps in it the car will have sour spots. I dont know why the ecms from the factory didnt have that. The stock tbi curves look like the swiss alps.

emisions.

What looks good on paper is about meaningless, tablewise.
Tuning is about giving the engine what it wants, not what looks good, or you think might work.

Some cars aren't too bad, but some run best with the hills of the Swiss Alps.

All right, thanks for all the input guys, I'll smooth it out a little more and then I think I'm at the point of just running it in the car once the engine is in and running. We'll see how everything turns out then.

Thats the type of ECU file i have. Do you have a link to the right one for the 7747?

The reason I gripe about it is it caused lots of sour spots when I put my 350 in. Some places where ok, in other placed it was just absolutly dead. I guess ,my motor isnt one of those.

I noticed that in Tuner CAT the X axis and Y axis are reverse of the TunerPro. Maybe thats how the program is written?

can you explain why the first spark table shows in some areas 50 deg. and the second table shows a more conservative looking table? where was that first table taken from?
in tunercat it asks for initial spark advance and includes that in tables i see as net advance. i have initial advance set to 10 deg which is what it was set at with timing light. i think TC also asks for spark bias? have not tuned for 4 months so not sure on that. but i believe it is set at 0. what is spark bias?

In the first table spark bias was 20.04 and initial spark advance was zero. In the second table I had zeroed out the spark bias and accounted for the 20.04 in the table, that's why its 20.04 lower all around than the first table.

what is spark bias?

All I know is that the Spark Bias is subtracted from the cells in the table and gives the real spark advance. Zeroing out the spark bias let's you see the actual timing in the whole table. I really don't see the point of the spark bias.

The spark bias' allow for negative timing to be added.

i believe in my tunercat my SB is at 0.

For a full explanation of the 7747 spark parameters, check this:
http://www.diy-efi.org/gmecm/papers/747spark.txt

Ben.

I'm starting to understand whats going on with tuning my ecm but I have some questions

Is there any caveat to running zero spark bias as long as I subtract that from all the cells in my spark table?

How come in this example(and in my chip) there is more spark advance at lower load than at full load?

If I set my SA to 36 at 3600 max load should I set my
Power enrichment added spart at WOT value to zero?

Is there another spark table for rpm's above 3600 or does it use the values from the 3600 rpm and above?

I'm running zero inital,
20.04 bias
I show 41.13 in my 100kpa 3600rpm cell that means I have 21.09 total total SA.

so I was thinking...

set PE at WOT to zero.

add 14.91 to my 100 kpa colum in the 2200 through 3600 rows.
add 12 to my 95 kpa colum in the 2200 through 3600 rows.
add 10 to my 90 kpa colum in the 2200 through 3600 rows.
add 8 to my 85 kpa colum in the 2200 through 3600 rows.
add 6 to my 80 kpa colum in the 2200 through 3600 rows.
add 4 to my 75 kpa colum in the 2200 through 3600 rows.
add 2 to my 70 kpa colum in the 2200 through 3600 rows.

set bias to zero and subtract 20.04 from all cells

that way I'll still have daily driver fuel economy at cruising rpms, and slope up to max at full load.

or should I add that gradual increase to all load colums 2200 up to 3600?


what do you think?

Zeroing out the bias is fine if you want to. Youll need to run more spark at low throttle then at WOT as your motor will bog and run like crap at part throttle. At WOT youll want less as teh dense mixture can detonate more easily. Start out with around 26 degrees of total advance at 3200-3600 rpm at WOT adn run around 35 in the mid-high rpm, low MAP areas taht you cruise in and see how that works for starters.

As for zeroing out the PE spark, thats fine as well. You wont need any more SA after around 3600 rpm anyway.