I ordered my injectors from summit and they were *supposed* to be #24 lb/hr SVO injectors. Well the invoice and box say that they are #24, but when I installed them and ran craigs software on them I was running extemely rich. BLMs were always at 108 except at WOT (which doesn't count). I thought at first it was my Fuel pressure, but I lowered it with no change in the BLMs. I resorted to asking and reading all posts. Then I started to increase the Fuel injector constant higher and higher. I got to 28 lbs and became concerned when no change occured. With 24 lb injectors I should have been running VERY lean (as I was when I had the vacuum leak) but I was still very rich. I could smell the gas out the exhaust. So today I had a couple of minutes and decided to increase the injector constant to #32 lbs/hr. This did the trick my BLMs went to around 134 which indicated lean. Finally but this kinda backed up my suspicions of getting the wrong injectors. This is were I need you guys tech expertise. I think that Summit sent me #30 lb injectors instead of the #24. That is the only logical explination of why it would be running that rich at lower injector constant setting. I should also add with in the lower injector constants I was only at 40 psi and still it was really rich. I am now at 45 psi and many areas are right at 128 with a couple slightly lean and a injector constant of 31 lbs/hr. The car feels pretty strong there too. OK here is why I posted it in the tech section. Is there any way that I can identify if these are actually #30 injectors. I noticed when putting them in that they looked like they were spray painted with a black *body* and they have blue plastic tops and brown plastic bottoms. I really never noticed if there were any numbers on them. Were would they be located if they had some ID markings. I am kinda POed that they are #30. I don't want to have all kinds of problems trying to tune them and I definately don't want to have to rip the SR apart again. 3x in two months would be just too much. I am going to call Summit on Monday and complain and see what they say. Perhaps some here can offer an explination of why the injector constant has to be so high to lean things out if in fact they are #24 injectors. It just doesn't make sense to me? Well thanks for the help....and what do you think i should say to summit.

Well, maybe I sould throw my 55s away since I have to run a 60 injector constant, not.

Seriously with the Battery voltage correction, and all the little trim values, I wouldn't worry.

Injector selection is guess at best and to get them right in on shot is a rather lucky guess in my book. It normally takes me 2-3 shots to get them right for my own cars.

If you search the archives, I do believe I have some notes worth reading about injector sizing.

What color are the injectors? If theyre Blue, then theyre #24.

Yeah, the 30lb SVOs are red and black. They also exhibit that same painted-over look that you describe. I have to agree with Grumpy on this one though.... Every engine and car is different and yours is just liking less fuel injector (constant) than you thought it would. I look at injector size as a kind of range of sizes that can be run and just use the PROM to get the ones you end up with to work with that particular setup. I knew the 30lbers that I have now were gonna be bigger than I needed when I bought them, but I didn't want to buy one set of FIs and end up changing things later on and needing bigger ones. I choose to err on the large side for the FIs and play in the PROM....

And if you have gotten it around 134 BLMs you are pretty d*mn close and I really wouldn't call that a lean *problem* ... It needs a little tweaking from there, but you are really pretty much right there on the doorstep, IMO...

Good Luck,
Matt

THanks guys. yes most of the RPM range and cells are at 128 but a few range into the 134 area. I will try lowering the constant back and see what the blm exhibits then. Thanks again for the advice and comments.
I will post the results as they develope. Thanks.

I seem too remember Grumpy stating on more than one occasion.."Give the engine what it wants...not what YOU think it wants.." cheers, Bob

Well fellas I got her nailed down now. All the cells and RPM ranges are within 2 blm or right on 128. Pretty good I must say for a novice! just kidding. I did pick up some knock at cruise that I never experienced before. Seems to start around 1650 RPM and at very light load situations. Tomorrow I will pull some timing from that area on the RPM vs Load vs Spark table. I also have some around 2200 rpm and high load situations. I will take that out once the lower is taken care of. One thing at a time to keep track of things. I suppose it wouldn't hurt to do both at the same time. I am not trying to break any minimum burn records. I noticed that the car kinda hunts at idle in park any suggestions. I suppose I could increase the IAC counts there. Just wondering if you all have a suggestion to correct it. I am also running about 134 blm there. I think that is due to the screens in the MAF being removed, perhaps I will bump the %voltage correction at idle to straighten that out. I think I read that about 2 months ago somewere. Well thank you all for helping. I might also add the car feels REALLY strong now. I found an ooops when gathering the data though. I adjusted the TV cable a bit the other day after logging and tonight after logging and looking at the data, the throttle is only 65% open! WOW and it really felt like it was ripping. I'll have to get that straightened out tomorrow and try it out again. Can't wait! Thank you all for your help!

I have always heard that the Ford injectors are rated at a lower (38 psi) pressure. Therefore a 24 lb SVO injector is really like a 26 pound GM injector. I have the 30 pounders and my IC is set at 33. That seems to be the right number.

If it makes you feel good, I have a basically stock engine with stock injectors. To get my fuel tables right, I had to increase my Injector Constant from 22# to 25.5#.

Also, as Bruce said there are a lot of other parameters that also work inconjunction. Batter Voltage vs PW, as mentioned by Bruce, Coolant parameters, etc. On SD cars, you also have the MAT tables to worry about.

The name of the game is to get the "major effect" with the injector constant as mentioned by the others. And then "fine tune" the other areas with other tables.

Sure wish I was that close!

SVO injectors are rated at Ford fuel pressure. I think that is 36lbs to 38lbs. Calculate what your new pressure is by using the following:

injector flow rating=

(new pressure/old pressure) square root X old injector flow

My SVO 36lb injectors, at 43.5 lbs of fuel pressure are actually 40lb injectors.