Injector settings?

[Aloicious]

Okay, So I've changed my intake on my '96 from running the crappy L31 poppets, to a MPFI intake running some common EV1 style Injectors like these:


I'm using a 411 PCM running COS 3 based off OS#12212156 for a 2002 express van. well, I've got it running and doing well, but I KNOW some of the injector tables like B4005 are off quite a bit from the poppets (the poppet injector B4005 stock table is almost ALL negative ), but I'm having a hard time trying to find another tune that runs this type of injector running the same OS so I can get the #'s from.

I know the C3500 on holdencrazy uses the same injectors, but the OS is way different and much of the injector tables don't transfer over.

Does ANYONE have a stock tune for anything running OS#12212156 and those EV1 injectors?

[Aloicious]

anyone?

any info would help out.

would the injector settings for the EV1 injectors be about the same as the EV6 that is fairly widely used?

the problem that I've got going on is basically the AutoVE is dialed in fairly well, for the most part, +- 1%. however I get a lean spike when the trottle is increased and a VERY rich spike (like down to 10:1 afr) when I let off the throttle. it happens at most all throttle increases/decreases, not just WOT. and the areas which the spikes occur end up averaging out to within 1% on autoVE (because the most time spent in those cells are durring driving, and the spikes are only at throttle changes), which is why I believe it is an injector tuning issue more than a VE issue...the real injectors work alot different than the stock poppet valves that were stock on the L31 motors. even if the injector settings aren't the full cause of it, I'd still like to get 'em dialed in correctly.

I'm not at my tuning computer tonight so I can't post a tune or log...but just mainly looking for the injector settings...

Thanks folks.

[joecar]

How to set those "other" injector tables is still a trial/error art unless you're able to flow measure injectors at their starting/stopping points...

If you have an oscilloscope you may (or may not) be able to see the lag between electrical and mechanical open/close events...

Hopefully someone will chime in with more info.


I borrowed this image from the picoscope website, I added the annotations:

[Aloicious]

How to set those "other" injector tables is still a trial/error art unless you're able to flow measure injectors at their starting/stopping points...

If you have an oscilloscope you may (or may not) be able to see the lag between electrical and mechanical open/close events...

Hopefully someone will chime in with more info.


I borrowed this image from the picoscope website, I added the annotations:

Thanks Joe, I don't have an oscilloscope here...I have one I can use, only problem is its about 120 miles away, and it is seriously from the 60's...

as far as flow rates, I did have the injectors flow tested and cleaned prior to installing them. so in the results, I have their static flow, pulsed flow @2500 rpm, and cc/min @43.5 psi. as well as their resistance test. the info I have is attached.

[dfe1]

The only significant difference between the EV1 and EV6 connectors is the connector. Before high flow EV6 injectors were a viable option, a fairly common option was (and still is) to install EV1 injectors, adapt the connectors, install fuel rail spacers and bolt everything together. You should be able to use a 12212156-based OS in your 411 computer, set the injector flow rate as required and call it a day. I wouldn't worry about opening/closing lag, voltage corrections and all the other injector minutia. You should be able to get things very close by working with injector flow rate. Once you get things sorted out, that you can play with the other stuff if you feel like it.

[Aloicious]

The only significant difference between the EV1 and EV6 connectors is the connector. Before high flow EV6 injectors were a viable option, a fairly common option was (and still is) to install EV1 injectors, adapt the connectors, install fuel rail spacers and bolt everything together. You should be able to use a 12212156-based OS in your 411 computer, set the injector flow rate as required and call it a day. I wouldn't worry about opening/closing lag, voltage corrections and all the other injector minutia. You should be able to get things very close by working with injector flow rate. Once you get things sorted out, that you can play with the other stuff if you feel like it.

Thanks Joe and Dfe1. I suspected the EV6's were pretty close to the EV1's, I've been running the 12212156 OS (well actually COS 3 of it) for a while without issue, but after the MPFI swap is when the issues showed up with rich decel, and lean throttle, so I was hoping to find another tune running the same OS and injectors I could just copy it and fine tune from there. but the poppet "injector" settings were almost totally opposite of any other calibrations I could find, so I knew they were way off when I swapped to EV1's.

I've got my IFR fairly well on (I used my injector flow testing data (average259cc/min), converted to gm/sec), and I've just swapped the injector info in from a 02 camero 5.7L w/ 12212156 OS, which, as I understand runs the EV6's, so I can hopefully fine tune from that.

Thanks again for the help guys.

[Aloicious]

Okay, so I've been VEing ALOT and have got the BENs fairly well in line, except for the lean throttle tip in, and rich decel, I've played with the VE table in those areas, as well as using the MAF and adjusting it's table, but the rich/lean issue just stays the same. I'll attach my most recent autoVE log with the tune it was run on. I have been playing with the B3701 table to try and solve the problem but its just a crapshoot with it. The injectors I'm running, I found out, are stock LT1 24# rochester injectors.

does anyone have the pulsewidth vs. battery voltage tables for these stock LT1 24# injectors? I'm having a crazy hard time finding them.

Also, for those looking at my tune, my VE table has not been 'smoothed' after performing auto VE at the recommendation of others, and it is actually running well (despite the rich/lean issues) so keep that in mind when looking at the VE table.

[hquick]

Hey Al,
funny this just popped up. I've been reading and searching all night for info on my 42's...but to no avail. I can't believe I should be using the same settings for my 42# as I was for the 19lb poppets (IFR excluded).

[Aloicious]

Hey Al,
funny this just popped up. I've been reading and searching all night for info on my 42's...but to no avail. I can't believe I should be using the same settings for my 42# as I was for the 19lb poppets (IFR excluded).

Hey Howard, thats my thinking exactally. especially since the poppets weren't actual "injectors", and if you compare the L31 injector settings to virtually anything else, there is some seriously strange things going on, like, compare the B4005 to any other vehicle, like a '02 camero which runs the same OS and you'll see what I'm talking about...

here's my theory on my lean throttle/rich decel problem:
take this chart showing what the PCM expects the injector to flow, its pulsewidth (under the red line), vs. the non-linear ACTUAL mechanical on/off flow of the injector (blue line)


so to me, when looking at it, first off, if the pulsewidth commanded by the pcm is too short, there is more flow (blue line) outside of the expected (red line), especially around closing, if the PCM commands too wide a PW, you get less flow under the expected causing lean.....now if the part labeled 'offset' is too large, even if the pulsewidth is correct, that would push the time of the actual injector flow later, causing a lean condition at injector opening, and a rich condition around the throttle closing. this is all ofcourse if I'm interpreting this correctly.

so in my experimenting with B3701, I've been able to get a rich throttle tip in, and lean decel (opposite of my current problem), but nothing inbetween and the rich lean extremes seem to be much worse, so I'm still using the L31 B3701 right now. this makes me think it has to be an injector setting of some sort. I also noticed that the L31 tables B3702 and B3703 (injection timing offset) is a bit higher and b3703 is different than everything else (again compared to every other stock tune using the same OS - '02 camero, '02 vette, '02 silverado, etc...all of which use the exact same b3702-3 but different B3701's).

so I may have to cruise around to some LT1 forums and see if folk there have the pulsewidth vs voltage information for the injectors I'm using. I bet the injector settings are at least partially contributing to your issues as well.

let me know if you find anything else out.

[hquick]

Well.....I did some searching also...and found some interesting info on 'the other peoples' forum.
The HPT forum has a 13 page thread on this exact issue..I just haven't had time to read it again and digest it properly.

http://www.hptuners.com/forum/showth...ht=pulse+width