I have them too, turned the fuel pressure up to 44#.....seems ok to me.....

 

 

 

I think the issue is that it has to flow 22 pounds per hour with pressure at 43.5psi so if you have a lower fuel pressure, you might get 19.5? IDK. Got a link to that article? Where did you get the injectors? Could it be old and/or dirty?

 

But do you have good pressure? Have you checked what it is when you turn the key on with the engine off? How well did it bleed down? Fast or slow? What is your fuel pressure under load at WOT?

 

 

Tried it briefly https://squareup.com/store/southBay-...-tpi-injectors

Is that what you are talking about?

If so, I'm guessing that since Ford uses lower fuel pressure it will flow less and hence the 19.5pph. I think I read something about that. Ask Jon since you got it from him.

 

 

You would be guessing correctly. As an example, the FORD "SVO" 24lb injectors in my 383 flow 25.5 in a 43.5psi fuel system. OTOH, my system isn't developing that much pressure...it's closer to the FORD pressure....making them flow 24lb/hr.

When looking at other types of injectors (than OEM), it's usually good practice to obtain electronic data "curves" for how they perform....to alter ECM parms accordingly. FIC is good about providing that data and will KNOW for sure what you can expect -- regardless of your actual pressure. They will work especially if you are tuning and don't have a huge setup.

L98's will go into dual batch fire mode -- which means injectors can perform a lot "bigger" than if in sequential systems. I used these exact injectors in a newer ODB2 setup and they worked like a charm...especially since they atomize better than our OEM injectors.

All this said, make sure you specify application (which I'm sure you will). In the back of my mind, I'm remembering Bosch III injectors can go "lean" under certain conditions (maybe idle)? FIC had a "fix" for that (in my older memory) where (I'm thinking) they use micro drills to enlarge the orafice to flow slightly more. To me, that means a different injector would be a better choice. I think this was a way to leverage a better-designed injector in our older setups w/o retuning. The next bigger size (B3) had it's own issues that also required retuning.

Fair notice: 7-8yr old memories involved here.

Conclusion: Answer to original question was answered by Aklim....meaning flow is dependent on fuel rail pressure (Ford vs GM)

 

 

Or...you could buy a Moates adapter, chip burner, chip(s), ALDL cable and tweak....plus have hardware for future changes/diagnosis.

 

 

 

IIRC, you have an 89 -- like me. That means we use the same BIN (parms).

The easiest thing to try is inputting injector size as 19. The smaller the ECM "thinks" the injectors are, the long PW will be as a default. Since O2 sensor feedback "takes over" once it hits closed loop, injector size might not help much. (Be aware changes w/o resetting the ECM don't necessarily react the same as a complete reset -- which includes trims. That said...

I would also try raising the "Closed Loop Rich/Leah Threshold" values. It's my understanding they "tell" the ECM where the swingpoint of the O2 sensor resides -- by a few rpm (airflow) ranges. To me, this is the only way to CHANGE how rich/lean you actually run during closed loop (though I've seen some evidence of transitional [throttle] differences after changing injector size and/or MAF table values...which may be a product of slower ODB1 computing speeds.)

You didn't say WHERE it's going lean OR under what conditions it's surging? My surges a bit on start-up. I think it's due to the engine being unable to stabilize at that low rpm when cold. So...it starts to falter then commands more air to speed it up....backs off, then repeats. I've added more fuel during open loop (around idle) which seems to help.

Oddly, I've also heard more fuel is "bad" for a cammed engine trying to idle during warm-up. OTOH, I'm better at understanding where/how to add fuel than I used to.

 

 

The thing I don't like about "rebuilt" injectors is the only documentation you usually get is static flow rate. Having the correct voltage offsets is important as it changes the flow rate greatly at lower pulse widths. I've had three sets of Bosch 3 injectors and fought a rough idle and low speed cruise for years. (even with BLM's at 128). I never blamed the injectors because they were "new", I kept changing other things. I ended up buying new Bosch EV14's, they come with charts showing flow rates from very small pulse widths to static, and voltage offsets at different pressures. Each injector is numbered so you know the flow rate for each of the injectors. It fixed my problem, makes a huge difference when the injectors are consistent and matched at small pulse widths too.

 

 

My under, which is standing is that you should be with 22. I think 85 used 24?

https://www.corvetteactioncenter.com/forums/c4-technical-and-performance/102559-fuel-injectors.html

My bad. 85 used 24 and others 22. I suggest you give Jon a call. I have verified his work before so I think he is honest enough

 

IF I recall right, my 85 had 24 # but Jon recommend that I use 22 # and raise the FP....been about 4 years and have had no problems...