Bosch 42# Injector Data Help Needed

[Supercharged111]

It seems every time I crack into either truck's tune I realize a jillion things I screwed up where I last left off. The 3500 is way less wonky and, surprisingly, it's more of a longshot being a mish mash of 350 and 8.1 stuff running a 454 pretty well. Well the time has come to make it right, preferably not the hard way that I've taken before. Where I was at yesterday was a properly running truck that threw a P1665. I intend to look that up on Mitchell as I suspect it pertains to the in tank MAP sensor that this truck does not have. What this truck does now have is a 2 bar MAP sensor and 42# injectors. I slapped them in at my hangar, flashed COS3 onto the existing tune, plopped the cal back in, did the recommended things per the tutorial, adjusted IFR, and drove home. I threw a P0200 on the way home and found an open circuit on injectors 6 and 8 so the plenum comes back off tomorrow to see if I'm retarded and didn't plug them in all the way or if they somehow developed open circuits after being ohmed by me and the guy who cleaned and flowed them. I'm leaning toward the former. I have 2 spare unflowed presumably usable junkyard injectors to swap in if it's the latter. ASSuming I can get that wrapped up in a timely manner, I want to make sure I have good accurate injector data plugged in for these things. They were used on the ASA LS1 motor way back in the day, here's a link to a thread with an ASA tune and a .txt document with injector data.

https://forum.efilive.com/showthread.php?20205-corvette-ASA-2000-tune-strange-spark-v-high

The document was uploaded by Mr. Prick who hasn't been around in forever andit claims to be a script. If it is indeed a script, I'm dying to know what I need to run it so it plugs all this data into EFILive for me if that's how it actually works. If not, the document is terribly copy/paste unfriendly. I PM'd him a few days ago and didn't hear back which I kind of expected. He's not been on in a while. I also forgot to plug in the damn vacuum reference line so hopefully between these 2 problems the truck idles like glass. The units on the document differ from the defaults which is why I just dumped IFR from the tune in post #1 in and drove home. I want to get the timing and everything spot on for this and I do have a 4 bar FPR like the LS1 did so no need to adjust values based on that like I had to on my 1500. Plan is to put the Whipple back on when the truck is right again, preferably tomorrow.

[statesman]

As far as I know, the ASA LS1 only ever used 36lb injectors. I wouldn't use ASA data with 42lb injectors.

[Supercharged111]

I'll have to dig up the thread that broke it down. I believe they are 36# at 3 bar (GTP factory pressure) and 42# at 4 bar.

Did some research, these injectors are 41.5# at 4 bar. Regardless of what they flow according to the internet, they are the ASA injectors. I jammed in the 5 g/s value from the ASA tune which comes out around 40#. I never changed the latency or any of the other stuff that's included in the .txt document. From what I recall, comparing an LS1 tune to an ASA tune, the only injector values altered were the IFR only. I'm going outside to pop the plenum off and address the now open circuit across injectors 6 and 8 and hope to have a decently running truck that needs only minor tweaking to be happy again. Since I am 4 bar this time around, I shouldn't need to alter any of the donor data.

[Supercharged111]

I went whole hog. 6 and 8 injector plugs were on, but not seated. Also forgot to reinstall the vacuum reference line for the FPR, truck runs better than ever now with non-leaky injectors. Hot restarts no longer require long cranking with throttle and dare I say transient feels much better? Was not expecting that. Just need to sort out all the injector data. Here's the quote from Mr. Prick:


The "ASA.tun" is junk. :sneaky:

Here's a script for the Bosch 0280 155 868 fuel injectors.
Bosch_0280155868_36 lb_injectors.txt (http://forum.efilive.com/attachment.php?attachmentid=9079&d=1285514630)


Note he claims the document is a script, which means if you press go it does the work for you correct?

[statesman]

With a speed density tune, getting the flow rate exactly right isn't nearly as important as getting the dead-time (voltage offset) right. With the larger injectors, you'll be idling deep into your small pulse table and your idle afr's will wander if that table isn't right.

[Supercharged111]

So piggyback question now: the COS manual stated that you must disable the MAF for 2/3 bar applications. Is that because they anticipate you'll peg it? If you don't peg it, what are the drawbacks to leaving it on? I guess I'll have to dump the data one by one into EFILive for the injectors. I get what you're saying with the small pulse.

[aaronc7]

I ran COS3 with MAF for a while before supercharging--no issues or anything. Like you said I think the manual is just assuming that you will be going to 2/3 bar SD only tune.

[statesman]

aaronc7 has already answered your question, but I'll say a few words as well.


So piggyback question now: the COS manual stated that you must disable the MAF for 2/3 bar applications. Is that because they anticipate you'll peg it?

Yep. If you're running low boost or operating the engine at high elevation, you'll be able to use the MAF sensor without any problems. Pegging the MAF is the only reason to disable it and run in SD.



If you don't peg it, what are the drawbacks to leaving it on?

No drawbacks... MAF is preferable to speed density. I'd recommend leaving it on if you're sure that you're not going to peg it.

[Supercharged111]

Is it ideal to cap MAF usage at 80% or something like most do with injectors? I know if the case of the flapper door air flow meters used by Toyota in the 80s their resolution sucked at the top end of travel, just wondering if a heated wire MAF like this would be the same? I'm headed to a lower elevation and looking to put a smaller pulley on the blower as soon as I get the fueling kinks worked out, just trying to see what my limits are here. Having previously run SD on my 1500, I overwhelmingly prefer to have the MAF playing as the truck seems far less affected by changes in weather and elevation.

[statesman]

The only reason you peg the MAF is that the PCM has a 512g/s limit... the sensor itself will read higher, so you can run right up to the 512g/s limit safely. Elevation changes can catch you out, so the amount of margin you leave for that is something you have to decide for yourself. Put the smaller pulley on now and you won't have to worry about it anymore.

[Supercharged111]

This is good to know. I will first address my fuel delivery, head to lower elevation with as much margin as possible, then do the pulley. I really do think I have the margin in the MAF tables for it, but the calc.vet probably won't happen before I leave hence me waiting to pulley down. I will then post up with logs and before/after tunes so my blending can be judged, I really suck at that and want to get better.

[joecar]

So, if you're running out of MAF (due to PCM internal 512 g/s limitation as statesman said), you can scale MAF/VE/IFR down, and shift all the tables that reference flow or mass.

[Supercharged111]

Oh yeah, I recall that being mentioned in my 1500 thread. And I lied, I'm going to pulley down after work today now that I know I have more than enough fuel for the job. I've got to wonder about the closed loop KR too, will have to grab a log of that.