OK, ive datalogged a few times w/ my new cable and win aldl. Ive got the tables. And i dont have a clue what they mean. I would really like a book to read up on everything, like how things should be and how to get them that way. any suggestions, or good websites? BTW, i got like 264 knock, oh brother, i bet that retards timing like a mother dont it?

Kinda off topic, but what is the difference between a prom and an ECM? is ECM the computer and a prom the 'software'(i realize its actually hardware, but it contains the info).

 

I would start here then ask more questions after you have read it.

Steve

 

Everyone always refers to that article, and its good and all, but it doesnt really explain what anything means. Are you getting into chip burning?
I guess a good place to start is the blms. Below 128 is rich, above and youre lean. You can adjust that in your fuel tables once u get an editor like tunercat, win bin, or gmecm.
Then, after the fuel tables are straight, you can play around with spark. The knock counts can either be from your timing being too advanced or from mechanical problems.
The books Tim mentions in the tech article are good references.

The ECM is the box-looking computer, and the prom is a chip.

Ken

 

if you subscribe to tunercat they will be very helpful online to consult during the tuning process. is your engine stock or mildly modified? If modified i would think it will be more involved as the tune is a fix for drivability issues. If stock i think all you will do is optimize the fuel tables and secondly possibly change the spark tables. i too am betting knock retard and am considering disabling the retard function or reducing amount of retard but still datalogging and looking for KC in my log. i suspect mine is mechanical. will need to listen for detonation and see how engine responds with no retard. customefis offers a book/manual but it is for people that build their own EFI using GM TBI parts.

 

Yea, ive read that article a few times, it explains more how to burn chips not what are the numbers and words are and what is desired.

Im getting into chip burning this spring, thought i'd get a jump on it during the winter when the mods go on while the car is in storage. To get all of this kind of stuff out of the way, you know, the learning process.

No big mods yet (see sig) full exhaust going on soon, under drivin pully. probally a single plane intake and 1.6 rr's if funds permit.

BLM=Block Lean Multipler but i dont know what that means
MAP=manifold absolute preassure....same

What tuning software would you guys reccomend a newbee get? tunercat seems pretty popular, how usar friendly is it? lookin for something free or close too it if its out there.

BTW, someone told me i prolly need a new knock sensor, seeing how mine is 15 years old i think they're prolly right. and the fact that im running w/o a muffler right now is prolly making several of the knocks !

thanks again,
-chuck

 

i use tunerpro myself.

 

Tuner cats does have one of the best GUI's out there, and its one of the most stable. Ive only managed to crash it a few times in xp as oppesed to some of the freeware ones, which i seem to manage to crash as soon as i open them . I dont know if its worth the 100 bucks for the eye candy, though. The definition files only have the bare minimum of stuff inluded. They have lots of breadth but no depth as far as teh tdf's go. The ecu's out there seem to have alot more stuff defined and they cost nothing so buying tuner cats is somewhat unecessary given the ammount of stuff out there. Save the money for the moates 'G2' adaptor. No switching capabilites yet but it allows you to ditch the 2732 eproms. If you want to make your own (note-some soldering required) you can include switching as well. Really nice because it allows for backup and alternate bins. As a note, though, if you get the adapter youll need a soldering as well as a desoldering iron to install it. As for learning, go over to the DIY-Prom board and read it religiously. Youll get answers to questions you never even knew you had.

 

i am new to tuning but i will take a stab at it. BLM: that is what shows in your data logging . 128 i believe is perfect stoich at 14.7/1 A/f mix. if you see 126 you are rich and ECU is making a correction. 130 lean and the same correction. the closer to 128 the better. ECU can correct faster closer to 128 and car runs better. in fuel table #1 you make correction and that is burning a new eprom. tunercat will help you on line by explaining their program and how to opertate within it. the engine science is not up to them it is your decisions on what you want to do. they may agree with you if you suggest you are considering this cause of that and you explain reasons you are making a change but they will not tune for you. they suggested i was on right track with my need for more pump shot in my car. MAP manifold absolute pressure. fuel table #1 is a function of rpm vs manifold vac. map 100 is WOT map 20 is idle or a high manifold vac for other reasons.

 

One of the things to keep in mind is that the BLM is more of a 'post-it' note for your ecm. It has only 12 cells to store values at and theyre esentially used to toggle to a previously stored value used to correct the fueling rather then rely totally on the 02 to determine corrections in fueling. Ive found that they only really give a good indicator of how the tune is when the engines operation is realativly steady and there are lots of samples. Make sure you dont do any highway driving either. As i found before i knew i had highway mode active all teh 128's skew the values.

The pump shot is kind of a pita w/o a WB as well. Ive just been using my butt to feel my way along where it needs it but i still think i dont ahve enough pump shot b/c i get detonation on throttle tip in even though my timing curves are realatily conservative. Anyway, im no expert but this is what ive experienced thus far.

 

that may be the answer to my KC! my PS may be lacking even though it is 200% of stock values. I started with a bin that was supposedly for a non modified 84 vette and kept upping the PS. Each time(10% bump) the stumble lessened when PE engaged. i may still add more but car stored as winter here. is highway mode enable flag in winaldl ?????????

 

hmm... what setup are you running? CFI? I dont know if HW mode was implemented at that time or not but [to my knowledge] all the tbi f-bodies had it enabled. To disable it (if applicable) youll have to change the thresholds where HW mode is activated. The only option my ecm has so far is to turn off the spark alone but i think its possible to completly disable it in other ecms by resetting the threshold where it is activated. Unfortunatly, tuner cats doesnt include this and other stuff in their tdfs, which kinda sucks.

From the sound of it if your getting a stumble when the ecm enteres PE it may be a mixture or timing issue, probably not an issue with the PS since most of the pump shot is only needed when the throttle is first open. There isnt much of a pressure change at high throttle loads in the manifold with an increasing opening of the throttle so there is less need for it. Adding in all the pump shot might just be momentarily covering up a problem with too much timing or not enough fuel.