1) I just started tuning over again, using ARAP bin. At idle BLM are @147. When just the slightest amount of throttle and blm goes to 128. INT stays @128. What tables should I tune to fix this problem.

2) There is also new constants on tunercat. They are min and max blm. What is this used for?

3) Im using SVO 30lbs injectors. I have pressure set at 48 with vac line off. In prom constants are set at 32 for single and double fire. Is my fuel pressure set too high? I read somewhere about Ford inj not having to run such high FP like GM. By setting prom to 32, does this balance so that I should run @48.

Any help would be appreciated. Thanks in advance.
Joe

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1987 GTA 355 miniram, lpe 219 cam,ported alum vette heads, T56, Currie 9 inch 3.70s, Gale Banks Exhaust, Spohn torque arm/crossmember,LS1 alum ds, cumstom burned proms

 

 

I've got the exact same problem as you #1 on three different cars I'm tuning with the ARAP chip. I havent figured it out yet...

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH (2.10 60')
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-

 

If your BLMs are high in general, then a change to the fuel injector constant can be made to make a global change affecting your BLMs. You should pick 1 fuel pressure setting and stick with it. I dont think 48 is too high.

MAF table#1 might be a place to start to help with your idle problem. I have found that slight changes here can make a big difference in your idle numbers. So, don't change things too much!!

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Best ET 14.413 @95.57 without
pulling valve covers or manifolds.
Also with stock 2.77 rear end!!!

 

I

 

When you have a better grasp of what your talking about before you might try making a call about something.

There is a huge difference from getting something to work, and getting it to work correctly.

Fudging the MAF because you have changed injectors and twisted the pressure way up isn't a correct move, to start chipping with.

 

That wasn't a cool move formula


Grumpy's the last person i'd ever tell they're "wrong"

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1985 Iroc-z, 14 second 305, new engine in the works.

 

On maf cars the maf table 1 will fix your lean problem.Look w/ a scan tool what your gram/sec is at idle.Then see on maf table one where the gr/sec is vs the counts.Take your idle reading and move it one count up on the table at a time until your running right..[/B][/QUOTE]
Ditto to the above-I just use the "percentage" method and it seems to nail it. eg-if the blm is 8% higher than 128, then increase the maf gps by 8% at that particular gps point on the maf table. If it lands in between say 8.4 and 10.9 gps where it runs lean then you'll need to adjust both points; if it's lean closer to 10.9 adjust the 10.9 more than the 8.4. Also make sure you let it really warm up first, or you'll be chasin' your tail! (been there done that) The "global" method of changing the fuel inj. constant is the first thing to do to bring the blm's close to 128 across the board first; then fine tune with the maf tables. After tuning a few vettes with maf I've found bigger cams and engines can be brought into 128 blm's everywhere with the inj. constant change except from 8 to about 20 to 40 gps. Then you'll have to use the maf tables. As for the blm limits-some folk (after getting it close) like to lock the blm at 128, then watch the int to further fine tune the int to 128. I've tried it-but it can be frustrating as the int responds very fast- you have to hit a load and gps and hold it there because otherwise the int shows "transitional" changes. Hope that makes sense the way I said it! Anyway that's what I've found. Also the lock the blm didn't work for me partly because I live at 7,000ft. and drive down the hill often. Hope this helps.


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86 406

 

Thank You everyone for all the great help. I think Ive gotten everything close now, although Im still experiencing a few backfires when I first go to move the car. If I let it warm up for 5-10 mins its usually small or non existent, but once the car is moving I can stop and go without problems. I still havent messed around with my spark tables much either.
Would anyone be willing to take a look at bin file, or maybe some runs using scanner. I think Im getting close, but I still feel like im going backwards sometimes.
Thanks again for all the help,
Joe

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1987 GTA 355 miniram, lpe 219 cam,ported alum vette heads, T56, Currie 9 inch 3.70s, Gale Banks Exhaust, Spohn torque arm/crossmember,LS1 alum ds, cumstom burned proms

 

I chat with both of you guys, so I won't get into a battle between you. But I will say the FEW times that I thought Bruce (Grumpy) might be wrong, it turned out my understanding was incorrect and I was wrong.

It's a cold day in hell if you catch Bruce incorrect on something. Which is completely amazing given he knowledge on so many ECMs. I am amazed he can keep all of those facts straight.

I will also say that with my SD, the one area where my BLM/INTs seem to vary is generally in the idle area. Because I can tune directly the VE tables, the variance is not as great as you are saying, but I do get a variance on my SD's idle from "day to day" depending on the weather.

The "dribble" theory makes sense to me and would account for my variations.

 

P

 

freely

 

>

 

Well both formula5 and Grumpy, along with sooo many others have helped me here, and in many situations. As much as I like to see the occassional dispute (with corrections of course), I hate to see people argue. Thank you all for your help, and if anyone would be willing to check out my bin and scans, I would really appreciate it.
Thanks again,
Joe

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1987 GTA 355 miniram, lpe 219 cam,ported alum vette heads, T56, Currie 9 inch 3.70s, Gale Banks Exhaust, Spohn torque arm/crossmember,LS1 alum ds, cumstom burned proms

 

The trouble is that you've made the error, if you were to sit down and look at the original posting you'd see where the error is. Just twisting values around to get things close is one way to do. Yep.
However, there are more correct ways.
I really don't care who you are, if someone asks a chip guestion, I'll answer it with the best info., I have available.
If you want to discuss something, fine, hitting rely and making a poorly informed statement gets you nothing.
There is no attitude in what I write, anything you see like that is because you reading something into my posting.

Different injectors have different flow rates. At the smaller PWs, they can be not very linear. This is also where the battery voltage corrections come into play. If you change injectors, the the first thing you'd normally do is change the injecotr size in the code, and Then look at what you have.
If as in his case, there is a low rpm problem, then the most common item to ACTUALLY NEED to be corrected is the battery voltage correction. If you make a fuel change then you'd want to make a fuel correction. If an air flow change then an air flow correction. These are where you need to start. Changing fuel corrects with an air change can be done, however, don't be surprised if in the cold run routines, or AE stuff there is another problem.

 

Could the problem be in the way the EGR is run by the ARAP code? I was having a severe lean problem at idle and in normal driving situations. I copied all the tables identified in TC's 6e.tdf and copied them to an APYU bin (89 TA). Everything fell into place. The car idles like it did stock (smooth as silk) and under most normal driving conditions I see 128s in the BLMs and INT.

I'm now playing with High Way mode working on my gas mileage. Next spring, when the track opens, I'll be working more on performance. (That, or I'll get a stop watch)

Sparks a flyin'

[This message has been edited by sparks383iroc (edited December 13, 2001).]

 

 

Formula, I know that you are doing a lot of "experimentation", much as I do. Some of the things I do is just not information that should be given to a newbie. For people that are well acquainted with prom burning and know when to "back off" and read the first signs of "trouble", I will share the info with them; but not a newbie.

Taking "spark advance" to the "ragged edge" is one of those things that should only be done by experienced prom writers. Running super lean AF ratios in Highway Mode is another along with playing with the "MAF Scalar" tables.

Lastly, there is "short term" and "long term" usage that needs to be considered. I have done things that "in the short term" do not seem to cause any problems. But in the long term, who knows. Right now, I am running a fairly lean AF ratio in Highway Mode that, in the short term, seems to work fine. But I may very well find in the long term that I am burning my cats out. I will let you all know in another year or two on that aspect.

I have played with the "MAF Scalar Tables" and while it is not a big deal for myself, I would agree with Bruce that this is definitely not something for the newbie to play with; it can cause more problems than it solves. I have also found that modifying the values in the "MAF Scalar Tables" often will correct on RPM/Load area, but cause another "RPM/Load" to be off. It really is a "balancing act where a compromise is sometimes required". Again, this is really an area for only the "experienced" prom writer to play with.

BTW, at what RPM do you find your 400 maxing the MAF (255 gm/sec)?

 

[QUOTE]Originally posted by sparks383iroc:
[B]Could the problem be in the way the EGR is run by the ARAP code? I was having a severe lean problem at idle and in normal driving situations. I copied all the tables identified in TC's 6e.tdf and copied them to an APYU bin (89 TA). Everything fell into place. The car idles like it did stock (smooth as silk) and under most normal driving conditions I see 128s in the BLMs and INT Hmmmm, There is something about the arap code...I just got done with a friends 88 vette. First I'd tuned it to 128's with the 32b tdf. Lots of mods on it- hot cam, ported heads, etc. Then he wanted to switch to the 6E arap. So changed values to the arap to start; and the lower maf flow's where suddenly about 6% lean! I've watched the egr open commands to try to correlate, but couldn't make it correlate. I can understand a big caution for newbies-at least if they don't already have a good understanding of how an internal combustion engine works! And yes, get the fuel press. etc. correct first-but I've tried the volt./pw correction for idle leaness; problem was consistency. If my fans kicked on (I've got the dual 11inch spals plus another in front), hot weather, (under hood temps up and volt. down) Or especially when that *&%$ alt. was going out again! Anyway, just my $.02 from what I've found to work/not work for me.



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86 406

 

 

So your talking about one specific engine, unlike the one that started this thread.

Sure helps if you stay on the same page.

If you stay at the ship biz, for another decade, you'll still be a decade behind me in time I have in chips.
I don't make these comments lightly, and misappling the info., is misappling it.
The only *universal answers* I've made here are in the *final answer* postings. The reason for this forum is for guys to gather info., for their specific application. You'll note my answers do vary a little, as they are specific to an individual.

 

Formula5, glad to see that you got your car running well, and you did it YOUR way. As you said, the MAF tables are the key to getting our cars to run correctly. Every motor has different airflow numbers, depending on many things. The stock GM tables are good starting points. But when you make changes, for any reason, in the intake airflow path the numbers will change. I burned a few chips this summer trying to get them correct. I thought I was going up a dead end road, but persistence paid off, and I got them good. My BLM's run about 128 +-6, much better than the rich numbers I saw before tuning. I am sure I could do some more tweaking when I get to it. I don't think I changed them much from stock. The great thing about PROM tuning is that when you make changes to your motor, you can change things in the PROM to account for it.

As far as that battery correction table, my take is that table is for high demands on your electrical system which could be seen at idle. IE, all lights on, fans, motors, heaters, killer stereos etc. Thus the bat volts might low, and you would need some extra fuel to keep her idling. But if your electrical system is up to snuff, then that table shouldn't really be a factor. I just don't like the way TC defined that table. From 0 to 25.6 volts, come on!! I think it should be from 10-15 volts, with a smaller step size between values. That way you would have more adjustability. A car battery normally runs in this range, don't you think? Acutally more like the 12.8v to 14.4v over most general conditions.

This is just my 2cents on this topic. I am not doubting anyone here.

 

 

I was kind of bieng an a$$ to you grumpy,sorry

 

Glad to see that you are making an apology to Bruce. Bruce is probably the most valuable of resource we have at on this Board IMO. Who do you think I turn to when I seek "greater wisdom"?

I am currently using my car as a "test mule" as I intend on rebuilding my engine shortly anyway. I am testing things I would NEVER recommend to anyone else - not that they are a "secret", but they are dangerous. Some are dangerous for even the "experienced" ECM'er.

The funny thing is that there is often "multiple approaches" you can take in your eprom burning that can "fix" a particular situation. (A "stumble" at a specific RPM and/or Load for example). Sometimes one of those approaches is better than another because one approach fixes "only that situation" while the other approach affects not only that situation, but others as well.

MAF vs SD's approach for the Fuel Tables is a great case in point. From my working with MAF systems, I find MAF affects fuel more "globally" and then it works in conjuction with the TPS% to determine LV8 - MAF's calculated Load Value. I am still studying the relationship and interplay between the MAF, TPS% and LV8, they are definitely more complex than my SD. There you just adjust a particular RPM/Load variable and you affect nothing else.