Higher pound injectors - worth it for my car?

Red03Mustang · Aug 2, 2005

Hey all. I've been looking at some higher pound fuel injectors. I figured they would help keep my car supplied with all the fuel it needs, plus keep the idle smooth since mine tends to get a little jumpy every once in a while.

I was thinking 24lb injectors. I don't really have any engine mods, so I was wondering if this would be worth doing or not. I have everything listed in my sig, which is pretty standard bolt-on stuff.

Don't our cars come stock with 17lb or 19lb? I was thinking 24lb would be a good step up if this is a good idea to do.

forpit2000gt · Aug 2, 2005

I don't recall if 03 comes with 19 or 21, but the 19lb will support well over 300 rwhp and you are no where near that.

jstreet0204 · Aug 2, 2005

Instead of just beleiving everyone that comes in here and tells you that you don't have enough mods to justify larger injectors, find out for yourself.
I noticed your sig says you have a predator. Use it to datalog the injector duty cycle. If you are going above 90% it is probably a good idea to upgrade. I don't think you will, just thought I'd give the info on how to determine it.

BTW you should already have 22's so if you are going to upgrade it is usually better to go much higher than what you think you will need since it is easier to make a large injecor act small, than it is to make a small injector act big.

03gtmustang · Aug 2, 2005

No reason why you should get new injectors.

forpit2000gt · Aug 2, 2005

what color are the injectors?

forpit2000gt · Aug 2, 2005

jstreet0204 said:
Instead of just beleiving everyone that comes in here and tells you that you don't have enough mods to justify larger injectors, find out for yourself.
I noticed your sig says you have a predator. Use it to datalog the injector duty cycle. If you are going above 90% it is probably a good idea to upgrade. I don't think you will, just thought I'd give the info on how to determine it.

BTW you should already have 22's so if you are going to upgrade it is usually better to go much higher than what you think you will need since it is easier to make a large injecor act small, than it is to make a small injector act big.

Without major engine mods or power adder, you will not need larger injectors than factory.

jstreet0204 · Aug 2, 2005

forpit2000gt said:
Without major engine mods or power adder, you will not need larger injectors than factory.

I know that smart guy. I told him how to prove it... And was saying that if you DID need to upgrade, you wouldn't want to take such a small step going from 22's to 24's

squares98 · Aug 2, 2005

03's have pink 21lb injectors

RedBullitt · Mar 13, 2006

well lol i was getting random misfires and the "fuel trim maxed" code before the nitrous... so yeah thats no fun. your injectors should be plenty fine for now, but its all in what you are GOING to be doing. if you will need them eventually, buy them whenever you want. remember, you will have to at least calibrate the maf. if you make a big jump in injector size you will peg the maf voltage and have to get different internals or new sensor.

ProCharger GT · Mar 14, 2006

I'd reccomend the SCT MAF if you ever get that far, just put mine on and it works great - mind you on the procharger setup, it's a blow thru design - Pro-M makes a Univer MAF that was the biggest POS I ever bought, couldn't calibrate it to work with my car even after sending it in twice. the SCT MAF plugged right in (after getting a hose adapter) and the car fired right up.

Mike97gt · Mar 14, 2006

RedBullitt said:
well lol i was getting random misfires and the "fuel trim maxed" code.

the "fuel trim maxed" codes you are referring to have nothing to do with running out of injector.

you are talking about po 171 and 174 codes for lean bank 1 and 2

what that is referring to is the pcm added more than 25 percent above the stock fuel trim and still can not bring the mixture to stoch. so the pcm sets those codes for lean bank 1+2

now you have to keep in mind that the PCM is pretty much blind at WOT because it is equipped with narrow band standard 02 sensors from the factory. thats why the pcm runs open loop ( no feedback) at WOT, because any feedback from the 02's is useless.

when these lean codes are set is usually at idle or other high vacuum situations, thats when you are likely to suck in unmetered air from a leak such as a broken vacuum line. this extra air causes the mixture to lean out beyond the 25 percent threshold that triggers the po171 and 174 codes.

the best way to see if you really need a bigger injector is to watch the injector on time and see what your af ratio is.

DropTopPony · Mar 14, 2006

new 30lber's 4 sale

Procharg: what SCT MAF did you get 2400/2800? I'm not sure if that would be overkill for me. I might just get a LMAF to go with my roots blower.

jstreet0204 · Mar 14, 2006

svttech76 said:
when these lean codes are set is usually at idle or other high vacuum situations, thats when you are likely to suck in unmetered air from a leak such as a broken vacuum line. this extra air causes the mixture to lean out beyond the 25 percent threshold that triggers the po171 and 174 codes.

To add to this. The main reason you see these codes during idle and low load conditions, is because the stock adaptive table is setup to only learn under these conditions. The table below is the stock adaptive table. Only the cells with a positive number are set to learn. All the cells with negative numbers are only applied to from the learning cells. The -11 means it is getting its adaptive data from cell 1 row 1 (idle) which is not an ideal situation. One of the benefits of a tune is to change these non-learning cells to learn and apply its own data back to this range.

ProCharger GT · Mar 15, 2006

droptopponynj said:
new 30lber's 4 sale

Procharg: what SCT MAF did you get 2400/2800? I'm not sure if that would be overkill for me. I might just get a LMAF to go with my roots blower.

I got the 2400 since thats what was available at the time. Honestly they look identical and are the same price, so I don't know the exact difference between the two. Regardless I don't think I will be anywhere near the 850 HP range to worry about pegging the MAF.

Mike97gt · Mar 15, 2006

jstreet0204 said:
To add to this. The main reason you see these codes during idle and low load conditions, is because the stock adaptive table is setup to only learn under these conditions. The table below is the stock adaptive table. Only the cells with a positive number are set to learn. All the cells with negative numbers are only applied to from the learning cells. The -11 means it is getting its adaptive data from cell 1 row 1 (idle) which is not an ideal situation. One of the benefits of a tune is to change these non-learning cells to learn and apply its own data back to this range.

nice post jstreet

you seem to know quite a bit about the EEC system. do you tune these cars?

jstreet0204 · Mar 15, 2006

svttech76 said:
nice post jstreet

you seem to know quite a bit about the EEC system. do you tune these cars?

I bought the tweecer several years ago to tune my own car, and I've spent a lot of hours learning this stuff since then. There are a few books on ford fi that I've read, but probably the most useful was the SCT tuning manual and the tweecer message boards..

01Steeda · Mar 15, 2006

well here is a question for ya. my 02's are switching randomly. the wires have been checked and all check fine. )2's have been changed and it still switches with no pattern. thinking it may be the EEC now. how much would i be looking at for a new EEC?

Higher pound injectors - worth it for my car?

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