I decided to post this here even though it probably should be in the ECM section. I guess its a tech question too. 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.
-jesse

 

Sounds like they are 30#'ers to me.

 

Your diagosis makes sense to me. I wish I could help you with the physical markings, but I can't. What to say to Summit? Exactly what you have said here. I would check the boxes against the invoice and catalog. If they are the wrong injectors, it is likely due to one of two situations. Either they were packaged incorrectly at the factory, or someone at Summit picked the wrong parts off of the shelf. As a partsman I've been in both situations. Just remember, Summit didn't make the darned things. Good Luck.

 

I think that SVO injectors are color coded for different sizes. Sorry don't know which colors are which.

 

Well, mine are 30#, and they are RED.. so there's a start. Anyone else have SVO's they know the size of?? I think the 24# are orange ..?


[Modified by Glock'94, 6:41 PM 2/23/2002]

 

Guys,
Thanks for the reply, but I just had a very bad thought come to mind. I would presume that the mistake came from Ford. This is my dilema now. What if I have a mixed batch of injectors? I mean some #30s and others #24! :eek: How could I tell? The more I think about it the more concerned I become with the idea. I really don't care if they are #30ers but I DO care if some are #30s and others are not. This really sucks. I would think if only acouple were #30s I would have reached ~128 somewere between 25 and 30. Not 31. Does that make sense. I am definately calling Summit and demanding some kind of resolution, becuase if I trash this engine, ie one or two cylinders running way lean because the rest are #30s. Well I am not being left with the bill. And I sure as heck am not ripping the SR back off to send them back. :cuss If they want to pay to have them sent back that is fine.
On a good thought I would imagine that the injectors are color coded from the factory for just these reasons. I have all *blue* ones now. Perhaps that can shed some light on the problem. I will keep you all posted as to the outcome.
I still would like to know if someone has a way of making sure they are all the same. I wonder if a resistance check or impedance check would be possible. That could be done right on the car as is. Well if someone know please share your thoughts. Thanks.

 

You should be able to read serial/model #'s off of them to make sure they are all the same. If they are different, that would be bad and you'll never get it tuned properly.

 

Guys,
Just did a search and here is what I found:

-Ford fuel injectors are color coded for easy identification. The top half color
determines the capacity.

Grey 16 lb/hr Stock for non H.O. 5.0's

Orange 19 lb/hr Stock for most 5.0's

Light Blue 24 lb/hr Stock for all Cobras

Red 30 lb/hr

Dark Blue 36 lb/hr

I have the light blue ones. At least that is what color the plastic is. But why would I have such a high injector constant? This is weird! Now I am scared again I am not getting a good reading. What to do...WHat to do....

 

when did you change your O2's last? perhapse they are faulty ... maybe the injectors aren't working right and are letting too much gas in.. dunno man...!

 

Has anyone got the 24# SVO's to work properly in an LT-1? I think I need new injectors based off an ohm test, and was considering the SVO's. Can I just install them and reduce the fuel pressure to 39psi? :confused: :boxing

 

those _are_ 24lbers. what you're experiencing is a difference in "slopes" between injectors.

injectors aren't a constant flow rate, they change flowrate based on pulsewidth. at small pulsewidths, like idle and light cruise, some injectors can be of a radically different size than their "rating."

it just so happens that bosch and hitachi 24s (they're almost identical in function, and are used interchangeably by ford - both light blue tops with either black or silver bases), are among the most linear injectors available. they're almost always close to 24lb/hr ratings. the problem stems from GM's programming, where they have built-in slope compensation for the stock injectors. obviously, that slope doesn't match the slope of the 24s.

i can't remember if my obd-ii lt1edit allows any kind of slope changes to the injector size, but ford software does. not only does ford software allow for different size high and low slopes, it also allows you to change the breakpoint pulsewidth (the pulsewidth at which the injector changes from one size to the other).

working with ford injectors is easy-peasy, because you just have to look up the slopes and breakpoints in the stock programming for whatever vehicle uses the injector size in question. for 24lbers, use a '93-'95 cobra. for 30s and 36s, different year t-bird SCs. for 42s, '99-up lightnings.

ford sells a 150lb/hr injector out of their motorsport catalog. now _that_ is a difficult to tune beast. it's an injector meant for something other than gasoline (maybe CNG?), and can behave like a 50-60lb/hr injector at some pulsewidths. those are impossible to tune properly, you mostly have to try and fix WOT, get idle/cruise as close as possible, then count on the closed loop operation to keep cruise/idle near stoich.

which brings me to another point... i've seen a few people talk about BLMs corresponding to how lean or rich their car is running. if it's in closed loop, this isn't the case. what those numbers tell you is how much compensation is necessary due to O2 sensor readings. so, unless you've gone beyond the limit of closed loop compensation, you're not necessarily running lean.

 

I'm certainly NOT an authority on injector facts.
If it wee me, I'd be forced to remove the injectors and
take them to an injection specialist.
In Dayton, we have "Dayton Diesel Injection Service".
They can set up and test individual injectors to see if they are
in fact running up to full potential.
From personal experience, they discovered some of mine
from a Holley Projection were barely running at all.
Naturally, Holley dis-owned me and their stuff and made my
supplier replace the defective "ONE" and not the other two.
But my point is that they can be tested for proper operation.
Good luck. This sort of thing really fries my brain :mad
and makes me wanna :boxing someone.

 

Guys,
Hey thanks for the advice and comments. Through some further reading including the above posts I think I am alright. I have discovered that others that have experienced similiar problems.
I also started studying the graphs I have and I think if I bring the injector const. down a hair more I should be running around 128 in all RPM ranges and cells. I feel much better about the situation now.
Thank you all for the great information. In situations like this is were the forum really is handy. THanks.

 

I think that Ford and GM rate there injectors different I think injectors that Ford rate #24 lb/hr is more like #30 lb/hr for GM.
I think I read some where people saying to get the Ford rate #24 lb/hr injectors if you are going to go to #30 lb/hr for a GM because they dont cost to much and are rated #30 lb/hr for GM.

Jay

 

I think that MSR hit it right on the button. With different parameters you must compensate for the different intended systems. For example a ford guy using GM #30 injectors would probably have a low 20 injector constant. Also GM rates their injectors at 43.5 psi. Ford is around 37.5psi. But I took that into account when I started. There are still other factors that need to be accounted for.
-jesse :cheers: