1. Does anyone know where i can find info on the tables and how they relate to each other? Or a good description of what they influence?

I am able to figure out most of them, but I am confused on what a few do.

2. I am using stock fuel injectors, why is the fuel constant at 20.8 #/hrs? (Using stock 1988 L98 injectors that I thought were supposed to be 22 lb/hr.) What gives?

3. What is the load factor (LV8)? And how is it calculated?

4. In the constants table, what is the MAF high error (33) threshold control and why would you change it/what would change by increasing it?

TIA

 

I don't know of any "manuals" on all the tables-for specific questions just post here.
The fuel inj. constant-has the bin been modified? You should change the inj. constant first to get your blms close to 128 "across the board".
The maf code 33-GM's original setting is to set the code if it sees over 45gps airflow under 2000rpm and less than 1/4 throttle. If you're setting that code-first make sure you've changed the maf relays and you don't have any problems with your wiring.
It is common with the larger displacement engines to need to increase the limits to prevent the code-raise it some-but don't disable it; so you'll still get the code set if there is a real problem.

 

Thanks for the info on the MAF threshold. As for the Injector constant...isn't it just that? Why can't I just plug in a 22 lb/hr injector if that is what I am using? And more importantly, I need a set of injectors and am going to order a set of the Accel 30 lb/hr ones. What is the constant for those?

I know that the SVO injectors are rated differently, but I thought that the lb/hr constant was at the GM standard of 43 psi.

Also, isn't there some FAQ somewhere about the tables? I don't want to become an overnight expert on them, just general info on what each table controls...

 

You need to check you BLMs and then adjust your injector constants. Burn a chip and check your BLMs again and so forth. There is no magic number to use. Everytime you change the constant you have to drive and check your BLMs. Eventully you will find a constant that holds your BLMs around 128. If you are getting your BLMs between 126 and 130 your are ready to fine tune.

 

Ok...Thanks for that bit of info.

However, I can't believe that GM was that half assed about it. Am I wrong to think that an injector constant expressed in lb/hr should be the same as the injector you are using? (The exception being the SVO injectors)

How did GM arrive at a constant of 20.5 lb/hr for the 22 lb/hr injector? Unless I am reading a non-stock bin....
I believe that they use FM (fxxxing magic) to arrive at a lot of decisions, but I didn't think this one was that way...

 

I have seen 20.5# as an injector constant - but it was an "aftermarket" and it was designed for a 305 (19#). Almost everyone that gets into eprom burning with a basically stock engine has noticed the same thing - GM purposely has made the BIN to run rich (sometimes pig rich). And this is even when people have lowered their fuel pressure below GMs standard (which is anything but a standard - great variation from car to car).

I suspect this was for warranty claims. On my SD car, even though I am running 22# injectors, I had to increase the Injector Constant to 24.5# to get my BLMs reasonably close (with low fuel pressure). At 46 psi, I had to further increase the Injectore Constant to 25.5# or I was running too rich.

Remember, increasing the Injector Constant (everything else the same) will lean the engine.

 

Wow...that is GM magic...

I suppose with a set of 30 lb/hr injectors at 45 psi, I can start at 32 lb/hr constant and watch the BLM's from there...

Sounds like I need to buy that Emulator for tuning purposes

About the BLM's...below 128 is rich and above is lean, right?

And Glenn, do you have a small listing of the tables in which you have dealt with regarding your friend's tune?

I would love to get a final copy of that bin, if you are so inclined to provide it, just so I can see how different it is from the one that I am using, or even the stock ARAP bin.

Thanks!

 

[QUOTE]Originally posted by 88TPI406GTA
Wow...that is GM magic...

I suppose with a set of 30 lb/hr injectors at 45 psi, I can start at 32 lb/hr constant and watch the BLM's from there...

If those are SVO injectors, 30# (rated @ 38psi) = 32.66 (rated @ 45psi). Probably a good place to start.

Sounds like I need to buy that Emulator for tuning purposes
Why? It takes me less than 2 minutes to take out my Memcal (with a Flash Prom installed) and reprogram it. I just leave the ECM on the floor of my car when I am making a lot of test.

About the BLM's...below 128 is rich and above is lean, right?

Yes, BLM/INTs below 128 means you are rich and the ECM is reducing fuel to get 14.7 and above 128 means you are lean and the ECM is adding fuel to get 14.7.

Glenn, do you have a small listing of the tables in which you have dealt with regarding your friend's tune?

I do not document or log changes I make to people that send me BINs review. I leave that up to them. Actually, I seldom make the physical changes, I prefer to make a recommendation and let them make the change. But the key tables we worked with were the PE %Change AF Ratio vs RPM (as he was maxing his MAF @ 5,000 rpm) and the Spark Advance Table vs LV8. Of course a ton of constants too, as he is running a 383 Miniram with AFR 195s Competition Port (2.05 Intakes) with no EGR nor Canister Purge.

I would love to get a final copy of that bin, if you are so inclined to provide it, just so I can see how different it is from the one that I am using, or even the stock ARAP bin.

I would love to give you the BIN, but it's not my property to give. I get a LOT of people e-mailing their BINs to take a quick look and possibly make some recommendations. They do with the understanding that it is THEIR BIN, not mine. And unless they specifically authorize me to release the BIN, I cannot. In the past, he has specifically said that he would prefer that I do not release his BIN. I hope you understand that I would do the same for you, if I was going to review your BIN.

But I can tell you right now that there is NO WAY you could ever run his BIN. It would idle wrong, run pig rich in WOT above 5,000 rpm, and most certainly cause audible detonation on your car. AND, we limit the amount of Max Knock Retard in PE to only 1* so we can control the spark curve but you have no "safety". This is a highly tweaked eprom to his engine, no one else.

You don't start immediately capping the KS to only 1* and start doing some testing when you are working on your spark tables. You have to slowly work to 1* or you will most surely detonate and now you don't even have a KS to pull some timing out. Yes, if done right you can get some extra power especially in the lower RPM range by bringing on the spark advance as quickly as your engine likes (without detonating) since you now have totaly control of the spark curve without the KS interferring and altering the spark curve "shape". But this takes a lot of testing if you want to avoid detonation. There is no "plug n' play" solution, just testing, testing and more testing.

This is why we don't recommend "capping the KS to a low number", especially to people who just got into eprom burning not too long ago. This is something that only those who have been burning for quite a while should ever attempt, and verly slowly and carefully. I have triggered "audible" knock more times than I care to admit playing with the spark curve before I finally found the right curve - but only for that engine.

But if you are willing to risk your motor (a cold, hard reality) and slowly work to spark curve, then you can get some awesome results. However, be forewarned that capping the KS to 1* in WOT is a very dangerous thing to do and is not recommended.

 

Since my ks is disabled ,my wot and various loads retard tables should be no fuctional,right? If so then "for me" it does'nt matter if my tables are @0 retard(GLENN)?I dont recommend diabling your k/s,406GTA.

 

I can't quite understand what you mean with the first sentence, but if you should have NO RETARD occuring in WOT (or any where else). I understand the difficulty with a 406 and you are kind of forced to "experiment" with different KS to find one that is "too far out in left field".

I am more concerned with "part/moderate throttle" on hills (as we have a lot of them where I live). If you live in a relatively flat area, then you don't have the same concerns that I do. Surprisingly, my buddy with the MAF 383 gets very little knock retard triggered in WOT. We are still having to tune the "part/moderate" throttle (due to those damn hills).

He's using the KS for the 1989 MAF L98.

 

Thanks for the great info Glenn...

I want an emulator just for personal preference reasons. I have read about the positives and negatives regarding it and I think that it would still make a good tuning tool for me to make small changesand experiment. You see, my plan is to initially play around with the total spark advance (starting with a smaller amount of total advance) and see if I can get my knock sensor working correctly. But mostly, I like the emulator for the idea of being able to change things on the fly. I already have a custom chip that seems to work OK, so that is my starting point. I also have a spare memcal that I will modify to use with the emulator, when the time comes. I can then take a few hours and drive around with a friend, get readings, make a few changes, then burn it into a chip and drive some more.

About the tables, I actually was just looking for a sort of glossary or description...and I do understand about not wanting an actual copy of the Bin of your friend as I don't want to just plug it in. However, I really don't understand the proprietary nature of not sharing Bins. As long as no one simply burns it and plugs it in without comparing the changes and/or no one is trying to make money from it, it shouldn't really matter. Just my opinion though.

I don't actually want any input as to how my bin is set up, rather just table descriptions. I have read the tuning tips at DIY-EFI.org and can only find some table descriptions for a few tables.

As for the Knock sensor, I agree...I want to get some readings from it first and try to get it working correctly. I think that starting out with a total advance of around 28-30 degrees initially would be what I would use. I would much rather start low and work up to find a good total advance.

One last questions. Can you explain the LV8 deal to me? I know that it is a load value, but am unclear as to what it means.

Thanks again...

 

I have a good post about timing @ different lv8.Do a search with my name and you'll get it.It has my theory on the main spark table.That table is very sensitive and can damage your engine.My engine will not even start if I change the main spark @400rpm.I am very careful and can detect knocks very well.Some people go too far and pay.But after you set up your fuel tables,constants the main spark table is most important table.I get 25mpg right now and I have yet to get mine optimal.

 

How did you fix your knock sensor then to give accurate readings?

BTW, check your email for a response.

Thanks!