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Messages - dennisL
1
« on: May 23 2013, 10:41:19 AM »
Steve, the analog inputs to PL are adjustable and saved in the ini file. Don't know if adjustments affect the SM display values but certainly affect the PL program. You can adjust the range (min - max volts) and the "OffsetVolts". The offset shifts the range slightly (plus or minus).
2
« on: April 27 2013, 10:26:00 AM »
Both the BL and INT values are limited by programmable values set by the chip maker. The stock INT limits are 100 and 150. If the INT value goes beyond one of the limits during C/L corrections, the INT value is clamped at the limit value and life goes on.
The stock BL limits are 105 and 150. After a C/L fuel correction is calculated, the BL min/max values are treated the same as with INT. Before writing (storing) a newly calculated BL value, it is clamped to the limit value. Now, if the ecm ever reads a BL value from memory that exceeds either the min or max value it will reset all the BL cells to 128. Since the BL value cannot exceed the min/max during a BLM write, reading a BL value beyond min/max indicates a corrupted number which is why the BL cells are reset.
[size=0pt]As for the percentage of correction, a value of 150 produces a 17% increase in fuel over the ideal 128 value. [/size]A value of 105 reduces the fuel by 18%.
3
« on: January 19 2013, 09:41:28 AM »
I'm thinking about getting an AEM digital voltage gauge and possibly their digital fuel pressure gauge, but thought I'd check here first. Steve, you have the voltage gauge right? Would you recommend it?
Anyone using the AEM digital fp gauge?
5
« on: January 04 2013, 02:44:01 PM »
That's what I suspected Steve, thanks. The voltage hasn't dropped below 13.0 at idle, driving, or wot, according to Power Logger so I guess its ok. I don't know how many amps my hot wired fuel pump draws at 18 psi of boost and since the alternator output probably goes down with rpm, I was concerned about that.
I feel better if you used a 100A for awhile and had no problems, but I'll start looking around for a replacement.
6
« on: January 04 2013, 11:56:42 AM »
I recently discovered that the alternator on my 87 GN is a 96 amp unit rather than the 120 amp unit that was there before the Buick dealer replaced it. This was done in 2001 but I just discovered it while cleaning the engine compartment. It seems to be working fine but ... Should I replace it with the proper 120A version? Will the 96A alternator negatively affect performance in any way or am I ok as long as I don't install a mega-watt stereo? I'm thinking that Buick used the 120A for a reason but I don't know what it was. Oh, and my male ego would appreciate it if you would keep this quiet. I don't want the general public to know that I have a tiny alternator.  Thank you.
7
« on: December 12 2012, 04:45:02 PM »
Yea there is ... and that's what I'm trying to get straightened out. Its called Acceleration Enrichment (AE) and I listed what the program does to create the "pump shot" in a previous post.
Here's what I've learned so far: the minimum pw for my 009's is 1.358 ms @ 145°F. The coolant temp. does make a difference, so I have to make the pw larger for colder temps. I've got the compensation for injector dead-time spot on and the AE is now responsive. A few more tweaks for very cold and it should be done. Oh, and during a test drive today I thought my BLM was broke because all the cells were 127 and 128. The log confirmed the ecm was learning to those values during closed loop. This is the best I've seen for this car.
Guys, thanks again for getting me pointed in the right direction.
8
« on: December 11 2012, 11:13:38 AM »
No throttle cracker modifier in that chip? Might help with that tip in lean spot... I'm not sure what you're referring to (?)The stock program triggers AE with a very small positive TPS increase (0.78%).The AE pw = Coolant Temp. multiplier x delta TPS.(There was another multiplier for TPS position, stock value of 1, which I removed).Add pw to sum of all previous pw's.[/size]The Max AE pw is selected by Coolant Temp.[/size]If the sum of AE pw's is greater than Max, then limit pw to Max. This is 99% of the time.[/size]Add injector battery offset to pw and squirt![/size]I'm not sure what I could add to make throttle stabs more responsive. 
9
« on: December 10 2012, 12:11:56 PM »
Thanks Mike and AJ. That Megasquirt stuff is very interesting.
Since I don't have a flowmeter or Megasquirt I'm using the engine and Power Logger to test. I can't measure the dead time but the AFR curve shows the effect of low pw's. I started with a very small pw (< 1ms) and am working my way up. I can see the AFR actually go lean at the start of AE when the pulse is too small. There is also a hesitation between gas pedal and engine response. I'm up to 1.3ms and should be able to test some more today.
Dennis
10
« on: December 08 2012, 12:50:50 PM »
My AE testing got slowed down after I decided to rewrite the AE portion of the program. There was just too much useless stuff, like multiply by 1, runtime multiplier, and more. I'm back into it now.
As to the minimum pulse width issue, I've learned that there is a min usable pw. Here's a quote from something I found:
[size=0pt][/size]
[/color]Injectors should not be operated below 1.5-2.0msec PW’s due to the non-linear portion of the curve. At extremely low PW’s, the injector’s coil does not have time to reach its magnetic potential, thus the opening and closing action of the injector becomes erratic.
[/color]
At a "too small" pw the amount of fuel is not predictable. Each make and size injector has its own characteristic but the 1.5-2.0 msec min appears to be the accepted practice. I've been using around 1 msec AE for my Lucas 009s but now I'll be testing 1.5 - 2.0 msec to see if I notice a difference.
11
« on: December 01 2012, 05:00:57 PM »
I just looked at the stock min AE pulse with my glasses on and its 0.488 mS. Big difference - that little decimal point makes.
12
« on: December 01 2012, 11:19:19 AM »
An 80 year old couple tells their doctor they want to have a baby but "nothing we do seems to work."
The doc tells them "take this jar down the hall to that room and give me a sperm sample."
After awhile they return and the husband is all sweaty.
He says "Doc, I tried my left hand then my right hand. My wife tried her right hand, her left hand, and even took her teeth out and tried her mouth. We just can't get the lid off this jar!"
13
« on: December 01 2012, 10:49:41 AM »
Thanks AJ. I have a scope but no flow meter so won't be making that test. The min asynchronous pw for stock injectors is set to 488 mS which seems large for a minimum. (  ) A few mSec makes sense for a true min and adding a margin of 100 - 150mS would seem reasonable to me, but I'm only a computer geek. I mess with this stuff for the education benefit and didn't want to break something if I made the pulse too small. I'll leave it alone for now as it only comes into play at hot temperatures and minimal tps increase. Each calculated AE pw is added to the previous total so the pw grows rather quickly until it reaches the max allowed. From what I see on Power Logger, most of time it jumps right to the max pw.
14
« on: December 01 2012, 08:53:44 AM »
With no pulse width you have no fuel .[/size]I was going to say something smart here but I'll just leave it at DAAAA.  [/size][/size]I think Dave makes a good point on the minimum pulse needed to pull open the injector but its interesting that the program makes the pw = 00 when the calculated pw is below the min. Almost as though a "too small" pw would cause a problem.
15
« on: November 30 2012, 02:10:15 PM »
I got side-tracked on the AE testing but now back into it. I'm looking at all parts of the program that deals with AE and understand the logic but I do have a question. Before the calculated AE pulse-width is applied, it is compared to a minimum AE pw. Can anyone think of a reason for having a minimum size pulse?
I plan to take the min check out and see what happens but thought I'd better ask the experts first. Does a fuel injector need a minimum pulse-width?
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