foxtrot

I have 110K miles on my stock injectors and I want to upgrade them from 19 lb to something a bit higher as I have a few mods.

Q1. What type of connector or injector type do I need? I see some on ebay but I want to make sure they will fit. Some say EVO typeIII etc??? Is there some standard name I need to verify?

Q2. Is there such a thing as mismatch in injector flow being too high? I know the 19lb is not quite enough as I am pinging at WOT high load condition in 5th. If I go to say overkill 30lb would that be too much? Is there a sweet spot in the fuel delivery band or will I still get what I need?

Q3. If I go with a 24lb/hr set would I have to do anything like change my MAF?

Thanks!

CalBoy101

Pinging at high RPM could be injectors maxing out but it also could be from the the fuel pump/filter not being 100% or from too much advance, has the car had a tune?

Keep in mind that one of the main things they do in a tune is bump your advance up and they might have gone too far.

Unfortunately the only way to know for sure if you are running lean would be using an in car AFR gauge or paying for a dyno run.

Does your 98 have the PI heads? If not the 19 lb injectors are probably ok if the rest of your fuel system is up to snuff.

If you are pretty sure you need bigger injectors the 24 lb ones will work and you don't have to change your MAF but you would need a new tune to correct for the bigger injector size. You can get a set of new FORD SVO 24 lb injectors for $229. They have a different style electrical connector but they come with adapters for that.

Another way to go is to get some of the pink colored 21's that were put on 2003-2004 GT's. You'll see these used on Ebay in the $100. range or so but they'll be used so it would best to have them cleaned and tested and that adds another $120. or so to the cost, about the same cost as the 24's.

foxtrot

Non PI heads
Stock tune never changed it. Don't own a tuner.


Ruled out vacuum leaks
Replaced PVC and hose assy.
Replaced MAF also with new.
Replaced fuel filter and pump (pump was bad).

Pinging tends to be noticeable after the the car is hot on hot days. I know this could also be carbon build up but I have done a the SeaFoam thing. Only way to solve that is a tear down.

Soooooo it might be my injectors as I say they are the originals from 1998 and the fuel here in AZ sucks SH#$%. So for $200 I can simply buy a new set throw them on and see if that fixes the problem.

This is less costly than a Dyno run and AFR set up.

What parameters need to be changed going from #19 to #24? and how is this done? I assume I need a tuner or have some one do this with one. If so I just upped the cost of going to a higher volume spray.

CalBoy101

Foxtrot, for your current mods I think your 19's have enough capacity but they could be dirty, causing your pinging.

If you can pop them out and wait for a few days I've had pretty good results having injectors cleaned, they test them after the cleaning and give you a chart showing exactly home much each one flows. In the past I've used witchhunter.com and they did a nice job but they have boosted their prices up a fair amount.

I just bought a set of the 21's I mentioned and sent them to mrinjector.us he charges $16. each and sounded like a pretty experienced guy on the phone so I'm hoping they come out well. You might also be able to find someone local to do the cleaning.

Going to 24's will cost you some dough and you're likely not going to go any faster since the 19's are probably enough flow for your engine.

You would need to get a revised tune that corrects the fueling for the larger injectors. You would gain a little HP also from this tune as they tweak the timing and fuel curves to give you a little more power, most of it comes at RPMS's less than the HP max but it will cut your ET down a little (maybe a tenth or 2).

I bought the combo SCT tuner and Bama tune service from American muscle, I think it was around $380. This is a hand held tuner that lets you save the original stock tune and replace it with one of their performance tunes. The create the tunes for you based on the mods you have and the type of gas you want to run.

You get "life time" free tunes (actually only free as long as you are still tuning that particular car). But if you are doing bolt-ons this isn't too bad, when you make change, like larger injectors, you give them a call and they email you a revised tune. Its not as good as a real dyno tune but for bolt-ons its not too bad, I'm pretty happy with it so far.

foxtrot

I hear ya .. looks like the most inexpensive move forward thing is get mine cleaned or buy some new/refurb ones.

Thanks for letting me bounce this of you.