My new combo listed in my sig., is running VERY rich. So rich, that running it for 2 minutes makes my eyes water and nose burn like hell! I have a custom PROM from fastchip (Ed Wright) and it was burned for my combo with 22 lb. injectors. I have two bad injectors that were pouring gas, so I switched to brand new 24 lb. SVO's. I then turned the fuel pressure down to 38 lb's (pressure with vacuum line on) and it's still running VERY VERY rich.

My question is: how do I change the injector constant and will this change alone correct my problem? Or, will other things have to be changed in the chip?

Thanks in advance for you guy's help!!
Mike (1bad91Z)

 

first off if u have scanning/burning equipment see what your car is doing and where your blm's are at , my guess would be in the 108 region which as rich as the ecm goes .......as far as the injector constant u will need to raise it to even it make it leaner
later

 

So changing the injector constant to 24 will lean it out enough to make the BLM's arround 128?

Bare with me I'm new at this!

Thanks again,
Mike (1bad91Z)

 

Yes, I think that increasing the fuel injector constant will lean things out.

If the ECM sees a bigger injector size, the ECM should calculate a smaller pulse width (PW) than previously.

If you can burn your own Eproms, I would change the fuel pressure to 48psi and set the fuel injector constant at 26.6#/hr.
(Thats what a 24# SVO injector flows at 48psi)

Pull out your scanner and see where the BLMs are at, now and after my above change.

 

With the Ed Wright chip that I have now (which is burned for 22 lb injectors) it's running WAY rich with the 24 lb SVO's. We've already established that.

I have a stupid question though:

Ok, Ed said that the car should run a little rich at idle (with 22's) and maybe a little lean on top until I get 24's and recalibrate the chip. So he programed it to shoot alot of fuel with the 22's. My question is, would it run is little less rich with the stock chip?

 

Something don't make sense, but alot of what Ed says doesn't make sense...If its programmed to be a little rich at idle with the 22's, its going to be way rich with 24's because the pulsewidth the injector is saying open is the same, and the 24's will flow alot more fuel than the 22's at the same pulsewidth. Sounds like he's programming for WOT only and not fooling with the VE tables which would be the coreect way once the injector constant is set.
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To answer your question, if Ed increased the fueling at idle, then yes, a stock chip will run a little leaner.
The correct way he should have done it was programmed the VE tables to keep the BLM's around 128 with the current 22#ers at all rpms and load including WOT (yes this takes alot of time, thats why you will never get a good chip from anyone unless you learn to do it yourself), then if you knew you were going to get the 24#ers soon, simply change the injector constant and reburned the chip.
You could have easily drove around for a little while while the 24# chip and 22# injectors as the ECM would compensate the lean condition alot better than the rich condition with the BLMs bottomed out at 108. BLMs numbers on the lean side can go up to 160, thats 12 more units higher than it can for the rich end at 108. Then when you got new injectors, you would have had to do nothing.....

 

Yea, I ordered the chip when I still had the 22's. The 24's didn't come into play until I found 2 of the stock injectors mechanical stuck wide open causing gas to pour out of my driver side header!!

Does changing the injector constant directly affect BLM's? And, since it's running that rich, would it be probable that gas is seeping past the rings of the new motor and getting into the oil? Will changing the injector constant to 24 be enough to lean it out with those SVO's (which I've been told they flow more than that), or do I set it 26.6 like DOC said to?

I'm pretty sure it will run better with the stock chip back in it, but how much power could I have a gain by using a "tuned correctly" custom PROM over the stock chip?

Again, please bare with me, I'm a newbie at the PROM stuff!

Mike (1bad91Z)

 

I also want to point out the following ...

I've seen several of Ed's chips so far for highly modded f-bods and all of them have been rediculously rich - especially at WOT. I think he's doing this to be on the safe side. Just keep that in mind. You'll probably need to work with Ed doing several revisions before getting it correct. OR - you could just buy the stuff and do it yourself.

Tim

 

Injector constant does directly effect BLMs, the injector constant is used to computing how long the injector stays open (pulsewidth). There is a fueling table in the chip that contains a value that also effects pulsewidth and it can be changed at variuous rpms/load combinations for fine tuning those specific areas that are rich or lean. The injector constant effects all areas of rpm/load.
I doubt its running rich enough to cause gas to flow past the rings unless one of you new 24#ers is stuck open, it would take more than just going up 2 or 4# in injector size with a 22# tuned chip to do that I would think.
You may have to experiement with the injector constant, if the SVO do flow more than advertised, then yes, it will not hurt to up it even further.
You will get the most bang for your buck tuning the prom yourself, cause then its your time, your not paying for someone elses time. For the proce you paid for that Ed Wright chip, you could have had all the software and hardware to burn your own and have $100 left over to spend on upgrades!! When you do it yourself, you can take the time to play around with the injector constant and the VE fueling tables...get all your BLMs in the 128 range, then starting adding a little timing, thats where the power comes in..be careful not to get any detonation, then go back adjust fueling again after doing the timing, you'll be amazed at the difference...all it takes is time. I wished I would have started doing it myself a long time ago, I could have saved at least $500 in various chips for my cars.
This board is an amazing resource for gather ing info for eprom tuning.

 

Set the injector constant for whatever injector your using, and then tune from there.

Forget the aftermarket, generic stuff, and tune for what you have.

And start with a stock bin, and make your own mistakes, starting with someone else's is often more misleading, and or wrong then you'd make.

Grab a copy of Tuning Tips from Incoming at DIY-EFI.Org

 

Cool then! I'm going to try to get my money back. I think I've only had the chip 30 - 40 days. I ordered 3 blank EPROM's (27C256-90) from JDR. A buddy of mine has all the equipment and a UV eraser.

I read TRAX's article (THANKS TRAX!!!!). It's ALOT of info to soak in, but I guess you gotta start somewhere!

So you guys please keep "tolerating" me, I have a feeling I'm going to need alot more help!

Thanks again,
Mike (1bad91Z)

 

Order a couple of the AT27C256 chips, they are electronically erasable so you don't even need the UV eraser light! They are only like $1 more each. Just pop them in the burner, and hit "program" and it programs right over the old without erasing.
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I got started from reading TRAX's articles, great info and you'll wonder why you didn't do it in the first place once you burn your first cut on a chip. Hopefully your prom holder thing already has a ZIF socket in it if its an aftermarket one it will. Otherwise you'll need to unsolder the old chip, and either solder in the AT27C256 or solder in a ZIF, I did not have to do this luckily. Then reread TRAX's article, he tells you a specific little piece to purchase and cut up thats for a printer ribbon cable, you can then use it to put in the burner without having to remove the chip from the holder each time.
I can remove mine and burn a new copy and reinstall in about 5 minutes now or less.

 

Wrong number, it should be AT29C256 for the 90-92 TPI's if that is in fact what you have. Sorry about that.

 

While I'm evaluating tunercat for 30 days, does anyone have the $8D file that they can e-mail me? I've read that $42 isn't all that great from what I understand.



Mike (1bad91Z)

 

I do need $8D file to burn a chip for my 730 ECM, right? If so, can anyone please help me? I have 3 blank chips and I'm going to try to burn one today. Is there a good starting bin somewhere on this board that is close to my combo or do I just copy the stock bin and make changes from there?

help......

 

Careful ....

No software piracy allowed on this board. The $8D costs $20 from TunerCat. You might want to e-mail him and ask for an evaluation version of the $8D.

Tim

 

Sorry TRAX, didn't know! I just figured it would be difficult to evaluate the software if I'm unable to use it without the proper definition file! I will e-mail them.

Trax - is there a good starting bin somewhere that is closer to my combo than the stock bin?


Thanks again!! I have read your article twice now and I'm probably going to have to read it again before I'm through!!


DIY - newbie,
Mike (1bad91Z)

 

I'd start with the stock bin, adjusting the injector constant which is in the "Constants Table" in Tunercat. Burn the chip, go for a ride with scan tool hooked up, if your still rich over all the rpms and loads you put on the motor while driving, go back and increase the inj constant some more, if lean, then decrease it. Once you find that happy median where your not rich or lean at all rpms and loads that you can achive, then start tweaking the fuel tables to achive the 128 or near BLMs all over the ranges as TRAX and Glenn have documented very well in some of the "Sticky" posts. Once the fuel is proper, then move on to the spark tables and adj spark upwards at the desired rpms and load, being very careful not to increase it too much because you don't want to start getting Spark Retard/Knock. Once spark is adj, then go back to fuel again because the timing increases will make it run leaner in those areas.
*
It will take anywhere from 50-100 burns/tries to get it like you want it.

 

I have recieved my 3 blank EPROMs today. How many times are they UV erasable and how long does it usually take to erase? Do I have to UV the new chips eventhough they are blank? Well, I'm going to try to burn my first chip tonight. I guess I'm going to start with stock bin, then change injector constant to 24, and delete all the emissions stuff and VATS (like Ed Wright did on my custom PROM).

Is there any other things I can change right away? The Ed Wright bin is a custom bin based off of a 1991 Vette with a six-speed. Should I maybe start with a 6 speed vette bin? Or what can I delete from the stock bin (auto tranny) wise?

I need help with-in the next couple of hours if possible (thats when I'm leaving to go work on the car).

Thanks again in advance for everyone's advice and suggestions (it IS appreciated)!

Mike (1bad91Z)

 

You should be able to get over 1000 burns on a chip before it starts degrading. It takes about 15 minutes on the UV lamp to erase, don't forget about them and leave them on longer as they will reduce the number of times you can burn it.
Your softeware that came with the chip burner should have a function to check the chip for being empty/erased, do this everytime to make sure it is erased before burning it. If the burn fails the first time, you'll have to put it back in the UV eraser again.
Another advantage of the flash chip I mentioned above, don't have to worry about that.
*
You could download the current bin off of the Ed Wright chip and start from there using your burner and the sw with it, you should be abale to read the bin off of that chip.
Probably be better to start there with the Ed chip rather than the stock one as I'm sure he's already adjusted various things that are pretty much standard changes on a performance chip. (I should have thought of that in my ealier post.)
*
What kind of chip burner do you have?
And I guess you got the right file def for the $8D from TC to edit the bin files?

 

A friend of mine has all the equipment, unfortantly I don't have the spare dough for it all right now. He said he had a pocket programmer II but was having trouble burning the EEPROM's (thats why I got the UV chips). He bought $8D today so we should have everything to do some tuning. We will be using Diacom to scan the car. If it runs a little less rich with the stock chip, I think I'm going to start there. Ed's chip is DUMPING fuel really bad, so bad that I'm going to take out the plugs and clean all the black soot off before running the car again!! Ed will not refund my money!! So I'm going to send it back and have him retune the WHOLE thing with 24 lb SVO's in mind. (I guess we'll see who's a better tuner, him or a newbie like myself!!!) And yes, I will post results of both chips!!

Thanks again you guys!!

Any other tips before I go work on the black beast?

Mike (1bad91Z)

 

The PPII is what I use, so you'll be able to read in Ed's bin file. Be sure you have the Device type set to the appropriate chip number/type you are using in the PP2.
To do the eeproms in the PP2, just set the device type to AT29C256 for the 90'92 TPI and I've never had a problem.
*
After you download the bin from Ed's chip, you can use the Tunercat function for "compare" and you can go thru each table and compare it to the stock bin. Once you open the stock bin file, then open the Ed bin file, go to the "tools" menu on TC and select the "compare" flag. You'll be amazed at how little is probably changed for the price you paid!!
I'll bet a few constants, a little VE here and there, and only Spark at 80+ KPa over 2k rpms or so, nothing else on the entire chip...
With a little time, you can tune your specific application better than anyone, because like I said before, its your time on your own car, not someone else time with only a limited amount of $ they can make.
At least you have someone that knows a little about how to use all the stuff, I started with just myself and this board.
Now all my friend are wanting a little tuning on the Turbo Buick side, I don't know anyone else with a TPI except a guy that does strictly LT1 tuning, but I've been showing him how to do the old style ecms and he's showing me how to do the newer LT1/LS1s.

 

That's assuming you believe the same tuning ideas as he does.

And if he was 1/2 close, the car wouldn't be pig rich.
Sounds like there's a fly in the ointment.

 

OK, Ed's chip had fuel ratio at 14.299 / 1 .

I changed injector constant to 26.6 and changed fuel ratio to 14.7 / 1. However I was unable to burn the new chip due to my buddies prorammer wasn't working properly, dunno why?

So I do have the new modified bin ready to go.

Does anyone in Houston area have a working pocket programmer II? I have the blank chips and the bin, just need to borrow someones burner!

mike (1bad91Z)

 

How'd you make out?

 

Might try posting in here.

https://www.thirdgen.org/techbb2/sho...hreadid=146086

 

Craig you have mail. (and thank you VERY much!) I'm using chip 25 constant for right now and it seems to be running a little leaner. After the car is running for a couple minutes, I have to occasionally nurse the throttle cause it wants to stall out. However, the oil leak is coming from the brand new rear main, so I have to yank the tranny again! (The history of the new motor is in my post "I finally have all the parts to finish the motor" in the after market product review forum. Man, I need that heated o2 and a laptop to ALDL cable. Do you sell that cable? Anyways, I'm going to try to fix the leak tomorrow. Hopefully my clutch disk isn't oil soaked!

Mike

 

Craig, did you get my e-mails?

Mike (1bad91Z)