How to: Fuel injector swap
Originally Posted by WS6FirebirdTA00
see a lot of people have the 38# injectors listed in their tables as 31#ers, i dont like to tell my computer a false injector size to get it to work, i want it to knwo the right one and then fix the computer to work with that
oh i agree 100%. dont lie to the computer.
but i highly doubt that a so called 38# injector truly flows 38#s at atmospheric pressure with stock LS1 PSI.
so to not lie to the computer, we have to say what this injector is really doing.
thats why the formula wont work right off the bat... not all injectors are linear enough that you can just go straight across and map them... thats why theres a table there instead of a constant and a formula in the PCM.
Originally Posted by RedHardSupra
ok, so what is the correct procedure to get your IFR tables perfectly calibrated to the hardware installed?
short of a graduated cyl, a injector mounted above it, and a stopwatch, i donno..
but thats why i think its a good idea for people to share what they have..
if one person does theirs good and shares
and another person does theirs and shares
and we see that "hey, all of these brand X injectors curve like this", then we're all better off...
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
yeah i see what your saying, i just thinking finding a curve for njectors would be hard, it woudl be nice if this information was supplied to us. although the racetronix ones rated at 3 bar and 4 bar pressure, which i assume they actually test these numbers, fall right in place with the formulas, so if they actually for them at these pressure and measure the fuel flow then we could use formulas to get them in the tables
Did injector swap today!! The step by step was great have some additions though:
1)Before removing the injector wire harnesses start with the drivers side. There is a bracket that is attached to the last bolt that holds the throttle cable. By removing this first it will free up A LOT of space.
2)As for the last two harnesses on the drivers side I did not take them off until we poped the injectors out of the manifold.
3)When taking the fuel rail out there is a fuel line that we kept attached (says caution fuel) we turned the fuel rail towards the drivers side so that the whole rail takes a 90 degree turn towards the drivers side
4)As for every thing else worked out great! Took 1hr 30 mins for first time. I had to mess around with tune though. Scaled it by what is was suppost to be 1.8xxx but was running too rich -12 LTFT so i scaled the table by 1.05 **twice** first time got me around -8, -9 second time (the tune I am at now) -4, -3. This is at idle and part throttle. Under 30% throttle the LTFT are right at -1.6, **0** Can't get any closer than that.
Getting FULL tune this Sat! Can't wait to see what kind of hp I will get out of the injectors???
Thread very helpful and I can not say thanks enough!!!!
1)Before removing the injector wire harnesses start with the drivers side. There is a bracket that is attached to the last bolt that holds the throttle cable. By removing this first it will free up A LOT of space.
2)As for the last two harnesses on the drivers side I did not take them off until we poped the injectors out of the manifold.
3)When taking the fuel rail out there is a fuel line that we kept attached (says caution fuel) we turned the fuel rail towards the drivers side so that the whole rail takes a 90 degree turn towards the drivers side
4)As for every thing else worked out great! Took 1hr 30 mins for first time. I had to mess around with tune though. Scaled it by what is was suppost to be 1.8xxx but was running too rich -12 LTFT so i scaled the table by 1.05 **twice** first time got me around -8, -9 second time (the tune I am at now) -4, -3. This is at idle and part throttle. Under 30% throttle the LTFT are right at -1.6, **0** Can't get any closer than that.
Getting FULL tune this Sat! Can't wait to see what kind of hp I will get out of the injectors???
Thread very helpful and I can not say thanks enough!!!!
if you need to redo your ve after new injectors, then your IFR is plain wrong. i swapped the injectors and my VE table was still in the -2 to +1 range across the whole range, perfect idle right away.
the swap however did take me like 5hrs, but i also have a 4point strut tower brace which is a biatch to take out...
the swap however did take me like 5hrs, but i also have a 4point strut tower brace which is a biatch to take out...
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
o yea i dont have that bracket on the back side of the intake, took all that **** out sorry i forgot about that one, thanks for adding, with that gone it takes me about 3 min to get the rail out
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Verdad Gallardo Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
i think i read one of them was suppose to hold the rail on incase of an accident, but if i get into a bad enough wreck where the 4 other bolts cant hold it down then i think i have bigger problems lol
Originally Posted by WS6FirebirdTA00
Step six:
...On the new injector o-rings you want to put some sort of silicon grease, be sure to get it on the oring only, on both of the orings, not doing this may damage the orings...
...On the new injector o-rings you want to put some sort of silicon grease, be sure to get it on the oring only, on both of the orings, not doing this may damage the orings...
Oxygen sensors don't like silicone.
It kills them, similar to how leaded gas kills them. Any silicone that makes its way down the side of the injector is eventually going to make its way through the exhaust. Gasket sealer was even reformulated for fuel injected cars so no silicone is present to work its way into the exhaust.
So I went back through and wiped them all down before I put them back on the engine. I'm going back to using grease or vaseline next time...
Originally Posted by John_D.
I had this comment in my head when I put my 60 lb'rs in a couple of weeks ago, and used some spark plug wire dielectric grease (silicon), and after lubing up the 7th injector, I recalled an important fact.
Oxygen sensors don't like silicone.
It kills them, similar to how leaded gas kills them. Any silicone that makes its way down the side of the injector is eventually going to make its way through the exhaust. Gasket sealer was even reformulated for fuel injected cars so no silicone is present to work its way into the exhaust.
So I went back through and wiped them all down before I put them back on the engine. I'm going back to using grease or vaseline next time...
Oxygen sensors don't like silicone.
It kills them, similar to how leaded gas kills them. Any silicone that makes its way down the side of the injector is eventually going to make its way through the exhaust. Gasket sealer was even reformulated for fuel injected cars so no silicone is present to work its way into the exhaust.
So I went back through and wiped them all down before I put them back on the engine. I'm going back to using grease or vaseline next time...
just FYI, even "sensor safe" RTV still effects them.
its just that household silicone will kill them in a instant.
automotive silicone wont kill them as fast.
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
Originally Posted by John_D.
I had this comment in my head when I put my 60 lb'rs in a couple of weeks ago, and used some spark plug wire dielectric grease (silicon), and after lubing up the 7th injector, I recalled an important fact.
Oxygen sensors don't like silicone.
It kills them, similar to how leaded gas kills them. Any silicone that makes its way down the side of the injector is eventually going to make its way through the exhaust. Gasket sealer was even reformulated for fuel injected cars so no silicone is present to work its way into the exhaust.
So I went back through and wiped them all down before I put them back on the engine. I'm going back to using grease or vaseline next time...
Oxygen sensors don't like silicone.
It kills them, similar to how leaded gas kills them. Any silicone that makes its way down the side of the injector is eventually going to make its way through the exhaust. Gasket sealer was even reformulated for fuel injected cars so no silicone is present to work its way into the exhaust.
So I went back through and wiped them all down before I put them back on the engine. I'm going back to using grease or vaseline next time...
