Go to tables on the menu bar, go to ECM constant table and open it. There you will see injector flow rate second from the top. Go ahead and dial it up to 30 lbs/hr. There you go!

 

I would start by getting the injector constant to 31 or just under. Then drive the car datalogging.

Then take the BLM's that you are seeing and divide by 128 and then take that # and multiply by the current injector constant.

So if you are seeing 150 BLM's, then take 150/128=1.1718, then take your injector constant, say 30, and take 30 / 1.1718 = 25.6 and you will have the new value that will get you to 128 BLM.

I honestly haven't messed with much more other than lots of VE table tweaking, but that is MAFLess stuff..

I don't know much on tweaking offset yet, maybe one of these days...

 

Thanks, I'll do that. The injectors are certified at 30.80. I'm at 29.99 and BLMs are pretty close to stock equivalent (24.87). This leads me to believe the offset vs voltage should be revised. Different brand injectors have different characteristics, open-close speeds depending on voltage. I found a comparison table on the web and will try those numbers. Someone told me that the delay also affects split BLMs somewhat but we'll see!

[ 11-04-2006, 09:52 PM: Message edited by: producers_kid ]

 

what kind of mods did you do to your car to neccessitate the need for 30lb injectors let alone the more expensive flow matched ones. If you got them for a deal, then that's another story

Anywho, you'll prolly find that you're going to get them close to dialed in with the injector constant in the mid 32lb range. Logically it should be lower, but many have noted that with SVOs 30lbers BLMS are where they're supposed to be, with the above indicated range. Plus that's usually where bryan sets them. not sure if my offset vs voltage would be the same ( I have non flow matched 30lb SVOs) but I can send you my values if you want to play with them.

 

I can send you my values if you want to play with them.

Appreciate it. If you need it email is producers_kid at yahoo dott com. These were $285 at www.gefracing.com and are matched to within 0.01 lb. I would have had to spend at least $100 to get my stock ones cleaned anyhow and I wanted to rule out lazy injectors. Also, I want to be able to better use E85 when it becomes available (though I've received conflicting info as to how much bigger the inj have to be for a stock engine +30-50%). Us tinkerers can never leave stuff alone.

[ 11-05-2006, 06:58 AM: Message edited by: producers_kid ]

 

I have been struggling with some split BLM's.

Is it more injector flow variance or is there something like ind fuel trims that can help?

 

I don't know. I tried tweaking the cylinder balance but get the smoothest idle with stock settings (no real surprise there). Quick thoughts: I have learned not to underestimate the effect of keeping fresh standard plugs and factory type carbon wires. Incomplete combustion shows as lean. MSD ignition made a HUGE difference on a previous car I had but it might make this computer go nuts.

 

Originally posted by RamAirRocket:
I would start by getting the injector constant to 31 or just under. Then drive the car datalogging.

Then take the BLM's that you are seeing and divide by 128 and then take that # and multiply by the current injector constant.

So if you are seeing 150 BLM's, then take 150/128=1.1718, then take your injector constant, say 30, and take 30 / 1.1718 = 25.6 and you will have the new value that will get you to 128 BLM.

...

I don't know much on tweaking offset yet, maybe one of these days...

It's a little more complicated than that. PCM has the following fuel map "table" it uses to store blms:

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> 0 900 1200 2000 redline
0 +-------------------------------+
| | | | |
| 0 | 1 | 2 | 3 |
| | | | |
30 +-------+-------+-------+-------+
| | | | |
| 4 | 5 | 6 | 7 |
M | | | | |
A 50 +-------+-------+-------+-------+
P | | | | |
| 8 | 9 | 10 | 11 |
| | | | |
80 +-------+-------+-------+-------+
| | | | |
| 12 | 13 | 14 | 15 |
| | | | |
100 +-------------------------------+</pre>[/QUOTE]* The table was copied from one of the Datamaster/LT1Edit help sites.

Every cell has it's own blms. A certain cell is selected by the pcm based on rpms and engine load. The easiest way to tune would be to adjust an injector constant so that all the cells are either lean or rich and work with injector offsets to correct the trims.

 

I am running 1100, 1500 and 2300 and 38, 60 and 75 boundaries to capture much more of the BLM cells. Stock BLM boundaries suck.

I use the Injector constant to baseline the table, then VE to refine it. But that doesn't help splits. I haven't found anything help splits yet.

Originally posted by Ram Air 9C1:
</font><blockquote>quote:</font><hr />Originally posted by RamAirRocket:
I would start by getting the injector constant to 31 or just under. Then drive the car datalogging.

Then take the BLM's that you are seeing and divide by 128 and then take that # and multiply by the current injector constant.

So if you are seeing 150 BLM's, then take 150/128=1.1718, then take your injector constant, say 30, and take 30 / 1.1718 = 25.6 and you will have the new value that will get you to 128 BLM.

...

I don't know much on tweaking offset yet, maybe one of these days...

It's a little more complicated than that. PCM has the following fuel map "table" it uses to store blms:

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> 0 900 1200 2000 redline
0 +-------------------------------+
| | | | |
| 0 | 1 | 2 | 3 |
| | | | |
30 +-------+-------+-------+-------+
| | | | |
| 4 | 5 | 6 | 7 |
M | | | | |
A 50 +-------+-------+-------+-------+
P | | | | |
| 8 | 9 | 10 | 11 |
| | | | |
80 +-------+-------+-------+-------+
| | | | |
| 12 | 13 | 14 | 15 |
| | | | |
100 +-------------------------------+</pre>[/QUOTE]* The table was copied from one of the Datamaster/LT1Edit help sites.

Every cell has it's own blms. A certain cell is selected by the pcm based on rpms and engine load. The easiest way to tune would be to adjust an injector constant so that all the cells are either lean or rich and work with injector offsets to correct the trims. </font>[/QUOTE]

 

Yes, each one is different for no apparent reason. Even splits are different between cells. That's why, to get a "perfect" VE or MAF table, you'd have to use one big cell and lock the BLMs to 128, turn off ALL PE, and then log to see what the integrators do over time, make adjustments until they are 128 consistently (or lock the integrators and log the BLMs). I'm not that dedicated (yet) or convinced that it would accomplish anything important in the end. Life is too short as it is, but I digress...

 

488
488
7782
7782
7782
7782
6073
3967
3204
2686
2258
1984
1770
1648
1526
1373
1251
1129
1007
885
763
671
580
488
397
366
336
305
275
244
183
183

Top is 0.0. through bottom to 19.6
Those be my offset vs voltage for my 30lb injectors.

sounds like you got a good deal on them. 30lb SVO FM injectors are now like $360. I got my NFM ones from Summit (through amazon) for $114. Had $100 worth of amazon gift certificates from the Gf's Aunt and Uncle

 

Thanks, Buffman. That's +183 over factory almost across the board. Looks like I have some logging to do. I'll let y'all know if I uncover something.

 

Originally posted by RamAirRocket:
I am running 1100, 1500 and 2300 and 38, 60 and 75 boundaries to capture much more of the BLM cells. Stock BLM boundaries suck.

I use the Injector constant to baseline the table, then VE to refine it. But that doesn't help splits. I haven't found anything help splits yet.

It's probably caused by a physical problem such as an improperly adjusted throttle body (high iac count/no idle passage hole/etc), an exhaust leak before O2s, unmatched injector flow between two banks, a vacuum leak or something similar.

There are "individual cylinder fuel trim" tables but I wouldn't recommend changing them unless you're 110% sure there are no mechanical issues.

 

Originally posted by RamAirRocket:
Stock BLM boundaries suck.

Agreed if you running a big cam.

 

Continuing the saga of going to 30# injectors for those interested, all else being the same, it looks like the above offset numbers lowered the BLMs about 5. Maybe it needs more. However, it has a lean stumble anytime the tps moves, especially cold, and will give a lean pop, EVEN THOUGH THE BLMs ARE CLOSE TO 128. Using Speed Density mode the stumble goes away so I think the MAF table needs to be scaled or offset. I'll do my tuning in SD mode first then match the MAF.

[ 11-09-2006, 08:27 PM: Message edited by: producers_kid ]

 

I am now at 31.81 inj constant. Increasing the Offset vs Voltage makes the BLMs shoot way down (removing fuel from the calculated amount) but the engine still has a brief lean stumble moving off idle, especially cold -- after all, it's coming off of pulling lots of fuel! Other than that it runs great and idle is smooth! What I think happens is this: The 30# Bosch "SVO" injectors are pintle style which requires a longer minimum pulse to get them to open - practically about 1.2ms to 1.3ms people say. But the factory "Low Pulse Width Injector Offset Adder Vs. BPW" curve, which acts as a cushion, is set for the smaller faster disc type Rochester injectors. So, with the increased offset vs volts, I was bouncing off the artificially high min limits beginning at around 1.6msec which is fine for 24#. This also makes coast conditions rich (Cell 2 @ 1.x msec) because the computer cannot pull any more fuel - bad for fuel economy. I can see why, with a stock setup, tuning would be very delicate (if possible at all) with pintle injectors larger than 30#. Anyone have any knowledge to share about this?

Also, the car runs really strong even though the BLMs are 150s. I am speculating that the Injector Constant is set artificially high to overcome these driveability issues: If you can't raise the bridge, lower the water! Therefore, if the computer is always adding fuel and your PE is correct, you'll never run into a lean spot crossing cells.

[ 11-18-2006, 10:01 PM: Message edited by: producers_kid ]

 

Originally posted by producers_kid:
I am now at 31.81 inj constant. Increasing the Offset vs Voltage makes the BLMs shoot way down (removing fuel from the calculated amount) but the engine still has a brief lean stumble moving off idle, especially cold -- after all, it's coming off of pulling lots of fuel! Other than that it runs great and idle is smooth! What I think happens is this: The 30# Bosch "SVO" injectors are pintle style which requires a longer minimum pulse to get them to open - practically about 1.2ms to 1.3ms people say. But the factory "Low Pulse Width Injector Offset Adder Vs. BPW" curve, which acts as a cushion, is set for the smaller faster disc type Rochester injectors. So, with the increased offset vs volts, I was bouncing off the artificially high min limits beginning at around 1.6msec which is fine for 24#. This also makes coast conditions rich (Cell 2 @ 1.x msec) because the computer cannot pull any more fuel - bad for fuel economy. I can see why, with a stock setup, tuning would be very delicate (if possible at all) with pintle injectors larger than 30#. Anyone have any knowledge to share about this?

Also, the car runs really strong even though the BLMs are 150s. I am speculating that the Injector Constant is set artificially high to overcome these driveability issues: If you can't raise the bridge, lower the water! Therefore, if the computer is always adding fuel and your PE is correct, you'll never run into a lean spot crossing cells.

the injector constant is set so high because they are 30lbs at whatever fuel pressure they are rated at. at our pressure they are like 32lb injectors.

 

Thanks Buffman. I heard that's a myth - that the injectors are now flowed at standard 3 bar (43.5psi) but I certainly don't know.

MAYBE SOMEBODY CAN TELL ME WHY the stumble gets better the higher the injector constant (I'm up to 32.8 and BLMs now in the high 150s) BUT THE PERFORMANCE IS GETTING BETTER AND BETTER! There is something I am missing here but I've noticed it before: Neck snapping throttle response and BLMs in the 160s! Anybody else notice this?

 

Are you tuning for ethanol or something? BLMS certainly in the 150s-160s are wayy lean.. The highest I had my injector constant was 32.47 and I thought @ WOT (running 93) it was a touch lean according to the wideband I was using. I ended up backing it down to 32.43 now the thing is running in the 11.9-12.4:1 AFR. guess it's time to play with the MAF table

 

Mostly E10 around here. You'd be real lean if the computer wasn't correcting for it or if blms are locked at wot. Maybe you're right about the maf (the injectors came with a disclaimer that they were for racing and the factory air meter settings would have to be adjusted) but I was taught that tuning should IDEALLY be done from scratch in this order:
1. VE table open loop
2. SD closed loop
3. MAF tables

 

Yeah the BLMs are locked @ WOT on my car. After talking with a few people they seem to think just moving the constant from 32.47 to 32.43 wouldnt have richened the AFR up that much, but it seems to have. So I'll have to tinker with it again when I can borrow my friends wideband some more and I dont have to worry about the outside temps being in the low 40s.

 

After passage of time and much trial and error, I have found that the response delay vs volts of the latest style red-top Bosch 30# injectors is actually slightly less than or equal to the factory settings. I had been seriously misled by the old data applicable to the former so-called "SVO" injectors and made the mistake of assuming that the delay should be increased 183usec over stock. This artificially long delay caused a lot of problems such as off-idle stumble, lean pop and almost stalling when coasting engine cold. Also, because the delay is an adder (not a multiplier) the factory VE table range was not correct and would have to be drastically mis-shaped to get the fuel curve correct.
So basically, having REDUCED the factory delay vs volts table by 31usec, reducing the IC back to actual flow rating, increased the overall PE vs Coolant Temp about 8%, scaling the MAF tables 106% (compensation for E10) and going back to the factory VE tables, the SOTP performance and throttle response off idle is about the best it's ever been -- on regular E10. No more stumble. I can post the bin when I get it dialed in just right.

 

Originally posted by producers_kid:
After passage of time and much trial and error, I have found that the response delay vs volts of the latest style red-top Bosch 30# injectors is actually slightly less than or equal to the factory settings. I had been seriously misled by the old data applicable to the former so-called "SVO" injectors and made the mistake of assuming that the delay should be increased 183usec over stock. This artificially long delay caused a lot of problems such as off-idle stumble, lean pop and almost stalling when coasting engine cold. Also, because the delay is an adder (not a multiplier) the factory VE table range was not correct and would have to be drastically mis-shaped to get the fuel curve correct.
So basically, having REDUCED the factory delay vs volts table by 31usec, reducing the IC back to actual flow rating, increased the overall PE vs Coolant Temp about 8%, scaling the MAF tables 106% (compensation for E10) and going back to the factory VE tables, the SOTP performance and throttle response off idle is about the best it's ever been -- on regular E10. No more stumble. I can post the bin when I get it dialed in just right.

so are the values I gave earlier (for offset vs voltage) an incorrect setting, or are they going to be different for you because you're running an ethanol mix? I don't seem to be having an issues with the settings..

 

Offset vs voltage table compensates for how fast injectors open at various voltage levels. Pintle injectors open slower than stock rochester type injectors. The difference gets bigger with size.

Extra 180 us (@ 12-14 V) sounds reasonable for 30 lbs Ford injectors. 42 lbs injectors need extra 350 us or so to open.

I don't see how anything other than fuel trims would be affected by the adjustment to the injector offset tables you describe. On the other hand, VE and MAF tables can make a big difference in driveability if the values are off.

Ford uses 39 psi of fuel pressure to rate their injectors.

[ 02-11-2007, 01:18 AM: Message edited by: Ram Air 9C1 ]

 

I cannot address your tunes because I do not know what other changes and/or tables have been modified, but there is more than one way to skin a cat, so I'm not surprised your tunes are working well. But, from what I learned, I would have been closer and saved a lot of trouble if I had followed the advice of 9C1'Soon to be married' Stangkiller and simply increased the injector constant. I'm publishing this to save others from making the same mistake, and I see there are others out there who are complaining of lean stumble off idle with these injectors.

Let me try to explain specifically why I believe there is lean stumble when the injector constant is too high: With a mostly normally shaped VE table (a nice rounded curve), the computer has a problem with pulling fuel in the very low MAP region and then suddenly adding fuel off idle when crossing into the next cell -- because it is off the curve.

[ 02-11-2007, 09:17 AM: Message edited by: producers_kid ]