Very High AutoVE values... Injector Size Identification?

[dc_justin]

Here's the background information. I bought a used Magnacharger Radix kit for my 2003 Silverado SS that was pulled at a dealership off of a trade-in vehicle. The kit come new with 42lb injectors.

I've set up the IFR table to 5.29 to account for this, as that is what I have read is approximately the proper size for these injectors.

Everything seemed fine until I picked up a WBO2 and hooked it up yesterday. I've got a 2 bar MAP and VE scaled accordingly (haven't gotten around to upgrading to custom OS yet). I followed the Auto Tune guide, disabling the MAF, Trims and Closed Loop operation, and scaled the VE up 30% rather than 15%, just to be on the safe side.

My problem is that even with this 30% increase, I have BEN factor values greater than 1 for most cells that I hit, and this results in VE % greater than 100% while I am still at 10" of vaccum. Intuition tells me that it's not possible for the VE values to be that high, and that one possible solution is that my IFR values are too high... I'm wondering if perhaps the dealership that removed this radix swapped out the injectors at the same time, but I don't know how to visibly identify stock injectors.

Any ideas on this or how to identify what injectors I have?

[Tordne]

Do you know what sort of 42lb injectors they are (brand - part #)?

To scale them we need to know at what pressure they are rated at 42lb, often times this is 43.5 psi, unless they are Ford Motor Sport injectors in which case they are rated at 40 psi.

Then you can use this spreadsheet (http://www.allmod.net/hpt/injectors.xls) to calculate what they should be on an LS1 at around the 58 psi mark.

Cheers,

[dc_justin]

I'm pretty sure that they are GM Marine 8.1L injectors. Not certain what this equates to at 48psi. Fuel pressure is vaccum referenced from 48psi to 62-64psi under boost.

[Tordne]

I missed the last line in your original post :oops:

There is usually a part number visible on the injector towards the top (connection to fuel rail). The number might be formatted similar to "0 280 155 931" which from memory is a common stock injector used in Corvette, Camaro and Holden vehicles.

Once you have found that part number you can probably search on LS1TECH or Google and find out brand and perhaps more information about the rating etc.

Good luck.

[Texas Terminator]

do you know what your actual fuel pressure is at the injectors?

[DrX]

I spoke to Magnuson today re: my crazy injector duty cycle values(my FP drops from 60 to 51 psi at full boost). They mentioned that their injectors are, "36(or so) lb/ hr injectors but 42 lb/hr at GM pressure."

So the flow rate depends what they mean by "GM pressure". My factory FP is 60 psi but this varies with model year/application. My tune from Mag has IFR set to 5.0 across the board(I think it should actually be ramped for my setup). I have a returnless non boost-referenced fuel system.

[caver]

The VE table is not actual Volumetric effiency it is predicted airflow and can easily exceed 100% the maximum value is 500%.
If you change the display to the default (Grams*Kelvin/kPa)it might make more sense.

[dc_justin]

do you know what your actual fuel pressure is at the injectors?

My fuel pressure gauge is tapped into the driver's side fuel rail and reads 48psi at idle, 62-64 under boost.

[dc_justin]

The VE table is not actual Volumetric effiency it is predicted airflow and can easily exceed 100% the maximum value is 500%.
If you change the display to the default (Grams*Kelvin/kPa)it might make more sense.
I understand that it can easily exceed 100%, and definitely should when in boost, however my values seem ridiculously high... EG. before I hit boost, my VE % are upwards of 120% and showing a BEN Factor of greater than 1 at that point

[SinisterSS]

Are the MAF and long term/short term fuel trims disabled in your AutoVE/speed density version?

[dc_justin]

Yes, they are disabled.
B3801 = Disabled
Maf High Fail Frequency = 1, limit = 1
Closed loop normal temp = 122

What about B4206, "Use O2 With Open Loop Commanded Fuel Table" ?

I never saw it mentioned in the guide and just now noticed it.

[dc_justin]

I missed the last line in your original post :oops:

There is usually a part number visible on the injector towards the top (connection to fuel rail). The number might be formatted similar to "0 280 155 931" which from memory is a common stock injector used in Corvette, Camaro and Holden vehicles.

Once you have found that part number you can probably search on LS1TECH or Google and find out brand and perhaps more information about the rating etc.

Good luck.

I finally got around to checking it out.

I found some numbers stamped on the back of the injector, but in a different format than what you described.

1143A
25176861

Mean anything to anybody?

[Tordne]

I think I saw numbers like that on the "back" of my injectors also. The actual part number that I quoted was found on the "side" or the injector. I did not remove the injectors so I need a high power torch to see it, it wasn't visible otherwise.

Not sure if that is going to be the case for yours. My part number format matches up as a Bosch injector, as do my new Ford Motor Sport 42lb injectors :wink:

[dc_justin]

I think I saw numbers like that on the "back" of my injectors also. The actual part number that I quoted was found on the "side" or the injector. I did not remove the injectors so I need a high power torch to see it, it wasn't visible otherwise.

Not sure if that is going to be the case for yours. My part number format matches up as a Bosch injector, as do my new Ford Motor Sport 42lb injectors :wink:

Hmm, I didn't see anything. Guess I'll have to head back out in a few and see what I can find.

Thanks.

Followup: Okay, both a co-worker and I went out and looked all around an injector using a portable halogen lamp for illumination, but could see nothing. I really don't want to pull the fuel rail to have to see this thing...

[Tordne]

Followup: Okay, both a co-worker and I went out and looked all around an injector using a portable halogen lamp for illumination, but could see nothing. I really don't want to pull the fuel rail to have to see this thing...

I know exactly what you mean. I was wrapped when I saw the part number which looked like what I had seen in other threads. You obviously checked on both banks, so you could see both "sides" of the injectors

I searched for (as have you probably) those numbers that you posted, but neither returned anything for me :(

[deezel]

I think most guys use around 5.10-5.25 for the IFR value on the Delphi marine injectors that come with the Radix kit. With a vacuum referenced regulator, that range seems to work.
If you have removed the vacuum/boost reference, I'm not sure what to tell you. Good luck developing your own sloped IFR table.

As for the open loop setup. I did disable the B4206 to turn off short term trims. Also keep an eye out for the P1514 ETC predicted air flow code.

[dc_justin]

I think most guys use around 5.10-5.25 for the IFR value on the Delphi marine injectors that come with the Radix kit. With a vacuum referenced regulator, that range seems to work.
If you have removed the vacuum/boost reference, I'm not sure what to tell you. Good luck developing your own sloped IFR table.

As for the open loop setup. I did disable the B4206 to turn off short term trims. Also keep an eye out for the P1514 ETC predicted air flow code.

I still have the vaccum/boost reference.
P1514 has bitten me in the arse a few times, usually right as I hit full boost at lower rpms. First time it came up I thought I popped the motor :shock:

My concern is that at 0 vaccum/0 boost and 4000rpms, my VE table is wanting a value just above 151%. The ONLY way this makes sense to me is if either a) my injectors are smaller than I think they are or b) even with the MAF disabled as recommended, it is still being referenced...

[EFIGUY]

Justin,

I think you might need to take a step back for a minute to get to the root of the problem...

Before connecting the LC-1 and actually logging the AFR you had a fairly decent running truck, right?

Then AFTER hooking it up, you logged some seriously "lean" AFR's and end up with crazy high VE values.....

If it were really that lean, then it would never have run the way it did before the AutoTuning attempt.

Most of the cars I have seen have VE tables that are pretty close for the stock engine when the MAF is disabled. Obvioulsy you would need to do a little more because of the boost (which is why you added the 30%), but you said your VE's were in the 120% range BEFORE hitting boost....that doesn't add up.

I'd take out a spark plug and see if it isn't all sooty and black.

My first suspicion would be that either the LC-1 is reporting the AFR vs Voltage values incorrectly, or the PID is defined incorrectly in your software.

Obvioulsy the problem here is that you are using an LC-1, not an LM-1 where you would be able to immediately see the difference bewteen what the Innovate is reading, and what the software is displaying. However, since you don't have that capability you don't really know what the AFR is.

I would try using someone's else wideband with an actual readout to see if you're really as lean as you think.....

If it turns out that you are actually that lean, then move forward with the freak injector investigation.

Hope that helps.

-Ben

[dc_justin]

For some reason as I was emailing you Ben, I figured out what the deal is.

There is no problem with the values I am seeing.
I've been lazy and haven't updated to a 2 bar OS yet and have been runnnig a scaled down VE with a 2 bar sensor. EFILive's VE formula to convert from % to g/cyl is what is causing my % to be so high. With my atmospheric pressure being 50-55kPa, the equation used needs to see a much higher percentage to equal the same g/cyl as if I were using a 1 bar map and at 100kPa.

Thanks for all the ideas and help. As with most things I do, the answer eventually just dawns on me, but would never happen without discussing the problem extensively with someone else. :lol: