Am trying to teach myself tuning basics. Not doing any actual uploading etc. Am leaving that to the tuner. I have both HP Tuners MPVI2 and EFILive (V1).

I installed Deka 80 signature series on my new TSP LQ ProCharged D1 370 - Camaro Z28 running perhaps about 10 to twelve lbs of boost. Was told the 60's would be borderline on gas (no plans to run e85). Rest of fuel system is spec'd up to 1000 rwhp on gas. Plan to tune for much less than that (maybe 650 -700 rwhp)

I need clarification on how to enter the data from the XL SS supplied by the vendor for the minimum and default pulse width values. Haven't received a reply from the vendor yet.

The EFI Live tables are B4003 and B4004. Both current tables contain values I assume were loaded by a previous tuner when the Mototron 60 injectors were installed.

The values are 1.276591 in each table. The description for units of measure is in milliseconds in EFI Live.

The new values to be modified reading from the XL SS for minimum and default pulse width is 0.125. There isn't any description stating if the unit of measure value is milliseconds or a percentage of a second.

There is a significant difference between 1.276591 and 0.125. That's a 98 percent difference. The difference in size between a 60 and 80 injector is about 33 percent understanding there are a lot of other factors when sizing an injector.

I am not arguing that 0.125 is NOT accurate, just want to be sure that is the correct value that I should enter in each table is 0.125 instead of 1.25. I don't want to assume anything.

Why do I ask? For example: 2.99 percent is actually .0299 when we calculate 2.99 percent of some value.

 

those are just minimum pulse widths so if you enter dfco or whatever, it uses that pw. they mostly come in to play for aggressive dfco or if you have injectors large enough that require a very small pulsewidth at idle. you will need b9021 as well if that is the case because thats an additional minimum pulse width setting

 

I am going to enter 1.25 into each cell instead of .0125 for minimum and default pulse widths.

I doubt seriously that the 98 pcm in my car and the pcm injector driver can squeeze pulse width down to 125/1000 th's of a second. So I'll just stick with 1.25 which is almost the same as the value for the Mototron 60 (which was 1.27 milliseconds). I still haven't received a reply from the vendor.

When I purchased the injectors the vendor suggested the Deka Signature series because I have a 98 with the stock PCM (not an 896 or 411). He said I could spend more money on injectors but would be wasted because of my PCM. He didn't elaborate why and I probably wouldn't have understood the technical details if he did.

This link appears to suggest if what is entered isn't correct can be more harm than good. Just speculating on my part but I think it should be 1.25 in the Excel SS instead of 0.125.

http://injectordynamics.com/articles/low-pulse-tech/

 

There's a few tables that get added together to arrive at your actual min pulsewidth. Often time you see the min/default and B9021 (min transient fuel pw) changed to very small values on large injectors, in order to be able to command a small enough pw to hit stoich AFR at idle/low load etc.

This info from EFI Live forum matches my real world experience:


I usually set B9021/B4003/B4004 to the same value, let's say 1.0 ms. Then min PW ultimately comes down to 1.0 ms + B3701. With my Deka 60 injectors, I found that anything less than 1.4ms commanded, they actually weren't really open or weird stuff happened. IIRC B3701 around 13.5-14.0 volts was 0.7ms. So I made my B9021/B4003/B4004 tables to around 0.7ms also. Which sets it up so min pw possible in any scenario is 1.4ms and I never command less than that. It will run a little rich 13AFR in very light load/decel cells, but I always reenable DFCO anyways, so it works out fine and no issues.

Before this I ran Deka 80s and they worked very well despite some of the negative things I read online. I did end up reducing the min pw tables even more, so it was able to idle stoich etc.

 

I recently researched this for my V and in very dumbed down terms, the way I understand it is you set you min PW low as a threshold for how short the pulse is allowed to be in milliseconds. If it is set too high, it will inject too much fuel causing a rich condition especially at idle.

the PW adder and injector offset from what I understand is like a “preload” for the actual injector PW because the mechanical movement of the injector takes a certain amount of time once the ecu gives the signal for the injector to fire. This lets the injector fire “on time”

im gonna stop talking at this point because that is the extent of my knowledge

derek

 

To address the actual question, I believe I used the 0.125 or something close to that when I had the Deka 80s. I believe a value of 1.25 will end up making min pw probably something around 1.6-1.7, which might result in a rich condition in idle or low load. You want it low enough so it won't make the car run rich, but now so low that you dont end up in situations where the commanded pw is so low that the injector doesnt actually open.

 

I would set your min pulse width to .8. That's as low as the stock ECU can command and it'll help get your idle AFR in line.

 

Thanks all

I reset values to 0.125 for min and default as shown in the table.

But probably have more issues. After looking at the current IFR table for Mototron 60 injectors it looks as if the only table that was changed from way back to when 42 lb injectors were installed was the IFR table (sloped due to static intank FPR).

All of the other tables are still stock and have never been changed. So essentially I paid thousands of dollars for tunes for the 42 and 60 lb injector upgrades (plus other engine mods) using three 'PRO" tuners and none of them bothered to setup the injectors correctly from stock values. Go figure.

FWIW - none of them suggested that I should change the FPR to a boost referenced FPR even though all three tuners were tuning for 8 to ten lbs of boost.

Unfortunately it was Racetronix that suggested that I needed to change to a boost referenced FPR. Suppose some will argue that it had an ulterior motive to sell me stuff to make the change. I don't feel that way. It was good sound information to know.

So learning how to tune and follow along to examine a tune file is helpful to know if one is getting what you pay for or NOT.

BTW - I won't be making the actual changes. The tuner will be doing that. But I will be checking to see that it was actually done.

 

I have a 98 PCM. Using EFI Live V1 I wasn't able to find B9021.

I have converted the 98 OS to the HPT Custom SD OS. I know that the backup VE table doesn't display in this custom OS. However a 2 bar Primary VE table up to 210 kPa is a substitute for the one bar Primary VE table (stock OS).

What I don''t know is what other tables were added to this custom OS for a 98 and if the B9021 table is one of them.

But it appears there are other enhancements such as:

Under the transient tab which a subgroup of Fuel there is a label named 'Min Fuel Milligrams'. Its definition is 'Minimum injector pulsewidth used to limit transient adjust fuel'. Might this be an enhancement/addition for the B9021 EFI Live table?

FWIW: the subgroups under Fuel > Transient for a stock 2004 6.0 Silverado OS is significantly less than the subgroups in the HPT 98 Custom OS in the Transient subgroup. Why am I a comparing an OS for a 6.0?. I have an LQ9 370.

It appears HPT has a naming convention for tables with a prefix of ECM. This particular table is ECM 2284. It's current value is 0.0000 after the conversion from my stock 98 OS to the the HPT custom 2 bar SD OS. This value of 0 makes sense if this table (B9021) was not in the stock 98 OS calibration.

In fairness to EFI live - V1 is 2005 time frame and it was free to 98 owners, EFI live did not spend a lot of time on it.

 

On 98s I had to get someone on the efi board to provide a custom .cax file to unlock the min fueling table to actually get it to command a low enough pulsewidth to get the idle AFR right.

 

Based on info from the forum on EFI Live the Mototron injector doesn't have very good idle characteristics. Perhaps because when I got them (2007) there wasn't a lot of good info. So it was a guessing game to get good idle.

Plus when searching trying to nail down the values for the IFR table I have found the values range from 72.3 all the way down to 62.5 (that's for an 1:1 FPR if running boost) where the same value (flat rather than sloped) is used in the entire table.

So what does it matter if I am switching to the Deka 80's?

For now I am going to see how far the 60's will take me. If I run out of fuel (at 80 percent duty cycle), it only takes about 30 minutes to switch to the Deka 80's and get back on the dyno.

Both tuners for my 98 pcm tune were using 69.3 at 58 psi as the starting value in the IFR table for the Mototron 60. It's my understanding that the Mototron is actually a Siemens injector. For comparison the Deka 60 values are 10 points higher than Siemens 60's.

Guess I will have to see what the tuner suggests and what values he will use when tuning for the Mototron 60's.

 

So B9021 was there in the 98 calibrations tables, just that EFI Live didn't include it in the 98 interface screens. Makes sense since it was free.

I suppose most simply switched to the 896/411 pcm where B9021 appears as a table.

 

Motortron 60lbers have always idled like stock on anything I've tuned with but I use Greg Banish fuel injector data.

 

Agree they should, but lazy tuners don't want to take the time like what happened to me - current tune is still using stock values.

I need to buy those CD's instead of wasting my time on the internet searching for answers only to find bad information.

 

Deka 60s? I'm using something pretty close to what's in the injector sticky on here. That should serve you well. I have no issues getting mine to idle or work at low pw.

 

Finally found a local tuner who claims to have 20 twenty years of tuning experience (that takes us back to LS Edit days?).

Background: Since my z28 is Procharged with the expectation to make at least 10 to twelve lbs of boost over the original D1 kit (about 6 to eight), I upgraded the fuel system to Racetronix dual 510 lph hour pumps, dual wire harness and fuel line kit with fuel rails and a 1:1 FPR with fuel pressure gauge.

I followed the installation instructions included with the FPR.

• Remove the vacuum line from the FPR.
• Adjust the fuel pressure gauge to 58 PSI.
• Reattach the vacuum line.
• Test readings when cold and after engine has reached operating temperature (some gauges are a little off once the glycerin heats up in the gauge).
• Change the fuel injector values based on the Siemens Deka file for the Siemens Deka 60 injectors. The IFR table was changed to 72.021 for the entire table. This value is clearly stated and highlighted in red on the Excel SS from the vendor. I verified this value with the vendor.

I also changed other values and tables according to the Excell SS. As stated in an earlier post, some of these values had never been changed from stock (three tuners).

Because I didn't want to drive the car much until I could find a tuner I left it as is except for a drive around the block to test that I could actually drive it on the trailer to be towed to the tuner.

Once on the dyno the tuner wanted to verify that what I had entered was correct. I supplied him with the file. When he looked at the fuel pressure gauge he said it was wrong and that it should read 58 PSI. The vacuum line was attached. Gauge pressure was about 48.

https://dsxtuning.com/blogs/dsx-tech...sure-explained

I attempted to explain to him that the gauge pressure should actually be lower than 58 PSI at idle. His reply was that he had been tuning cars for twenty years and that this is the way he tunes and have never had an issue. Rather than get into a full blown argument I relented thinking that when the car is NA (idle to WOT) the pressure will regulated from idle to WOT and that he will account for it while he tunes. What I didn't consider is what happens when the engine starts to make boost. At the time based on a reduction in pulley size I was estimating it would go from 6 to 8 lbs of boost perhaps to as much as 10 to twelve lbs of boost with the smaller pulley.

He spent almost 8 hours on the dyno. It is a load bearing DYNO jet. At the end of the session it only made 8 lbs of boost. The engine made 637 lbs of torque and 598 rwhp. I'm assuming he did all of the correct things such as spark, timing, and AFR etc.

When I got home, I did a read of the tune. I have HPT MVPI2. I wanted to make sure I had saved copies of his tune. What I discovered is that he changed the IFR table back to a sloped table rather than leaving each value at 72.021 as recommended.

Disagreeing with what I discovered I called the vendor. The vendor agreed that I was right and that he should have left the IFR table flat lined and well as setting the FPR at 58 with the vacuum line removed. Then attach the vacuum line to the FPR.

The vendor said that one way to fix it is to remove the vacuum line. But IMO that won't account for when the supercharger starts to make boost. With the FPR set at a static 58 PSI of pressure as boost increases effective fuel pressure actually decreases on a 1:1 ratio .

It should be the opposite. At 8 lbs of boost, the FPR should increase pressure by 8 PSI. But it won't do that with the vacuum line disconnected. Effective pressure will be 50 PSI when it should raise to 66 PSI (58 + 8).

Perhaps this is why it took longer than expected. At vacuum < WOT fuel pressure was greater than it should be and when in boost it was lower than it should be.

And the discrepancy will get worse as I pulley down to increase boost to the desired level of about 10 to twelve lbs of boost.

So what to do? Taking it back IMO is futile. If he has been tuning this way for years on hundreds of cars I doubt he will admit his method is wrong. He pretty much said that yesterday,

 

Your story reminds me exactly why I got into tuning / being more involved in the tuning process. I would find a new tuner

 

His method is incorrect. You are correct.