i just put in some big dog injectors and i reprogramed the flow rate with ls1edit but i am showing +25 ltrims, from what i understand that is way lean, i haven't driven it for long but and am kind of afraid to not knowing how lean it is.

here are the numbers i used

stock injectors were 21.8lb/hr@58psi or 2.74gm/sec
then i used some 41lb/hr@58psi and i punched in 5.16gm/sec, my ltrims were great with these injectors
now i just put in some 50lb@43.5psi injectors, my math tells me they are 58lb@58psi and that should be 7.3gm/sec

thats the number i put in and my ltrims are off the chart lean, what did i forget?

 

When I was redoing mine recently, I went back to a stock program, with flowrate adjusted fro my svo's. ltrims were 25% 24/7. So I just dropped the whole table by 1 until they came down. Haven't fine tuned it yet, but they aren't at 25 anymore. Plus the pcm is designed to handle some variation, otherwise, we wouldn't need ltrims in the 1st place.

 

Don't sweat it. You math looks right.

For some reason, there are some injectors that the math works great for, and some that don't. It think some injectors flow different rates at different pulsewidths which causes these odd LTrims but accurate WOT running.

Just reduce your injector flow rate table until the Ltrims get under control. After this, you will probably be running rich up top though, so you may have to retune the PE table.

Good Luck,
Kevin

 

thats reasuring, i thought maybe i had a vacume leak or something, i can't see anything wrong and it runs prety good.

how about this, my ltrims are at +25% at idle and always positive the rest of the time but the number varies, i think it just hasn't learned it needs to be at +25 yet. isn't +25 lean, the computer is adding fuel? well it sure seems rich to me, burning my eyes rich and sucking up the fuel. do i have it backwards? is +25 rich and i need to pull fuel?

 

Almost sounds like a vacuum leak? Thinks it's lean and running rich as Bill Gates <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> I don't know why there would be a vac leak though just changing the injectors.

Those injectors are BIG and may take some tweaking to get them dialed in. Be careful because +25 is as far as the Ltrims go. What do your O2's look like at WOT? You might want to do a real short blast to get an idea.

John

PS - Paypal has been sent. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

<small>[ December 06, 2002, 05:53 PM: Message edited by: XLR8NSS ]</small>

 

so just to confirm +25 means that it thinks that it is lean?, how could a vacume leak make it "think" it was lean without actualy making it lean?

also how do you check for a vacume leak? i tried shooting some carb cleaner at the questionable spots and didn't hear any change in rpm. i am concerend because the ltrims don't seem to match the rich smell and i did have to work those injectors in there, they are about 3/4" taller than stock and thru off the fuel rails and especialy the fuel cross over. i also ditched the egr set up and put in a block off plate so there are places that it could be leaking. how do i check cause i sure can't hear it.

 

I don't know what I was thinking. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> <img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" /> It will be lean with a vacuum leak. +25% means it is lean and the computer is adding fuel.

If you messed with the EGR I would definately check to make sure the block off plate is sealed good. Maybe try some RTV sealant around it. It doesn't take much of a leak to send the Ltrims that high.

As long as you don't have any fuel leaks around the injectors/rail you should be good there.

Usually if you have a vacuum leak the idle will be very choppy. I have purposely unhooked the PCV before and the car would barely stay started.

I don't know what to try next. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

John

 

A lot of the larger injectors (especially 42 lb) are really non linear. You may have to scale them so they flow a lot less down low, even if they are fine at the top. You should not just change the whole range in the pcm unless your fueling is consistantly low or high through the whole range

Gary

 

i used 6.XX for my SVO (50lbs) injectors, seems to work fine.

 

Sounds like you need to adjust the injector offset. The bigger injectors require more voltage to open fully and therefore probably require much more offset at idle. I hear the 50# are pretty hard to get right.