Need some help figuring out problem....just finished my 350 hsr project...afr195 heads, xfi 268 cam, 1.6 rr, ford red top injectors....now finally was able to start car and and runs extremely rough and rich....i know ill need a tune but was hoping i could atleast have it idle right...im in the process of figuring out whats wrong( check codes, fuel pressure, etc) but wanted to know if a tuned chip is required at this point??? Thanks in advance

Btw have only messed with timing..need to buy a fuel gauge

 

Most likely, yes.

Those would seem to be a bit on the large-ish side for a 350; not necessarily "wrong" or anything, just, kinda large, as in, maybe outside of the range of whatever your ECM is expecting or able to deal with (which isn't a whole lot if it's stock). Try backing off the FP and see if it improves. That's not the "right" answer, but at least it'll tell you which way you need to go next.

 

Always helpful sofa thanks!!!! Will check fp and try backing off pressure

 

Are these 30#hr injectors ? If thats the case yes back the pressure off to 3 bar.
You need to start tuning , You didn't state which bcc you are using hopefully its a anjf or aujp. I would start with a axcn and set the injector constant then work on the ve in 30-40 kpa.

 

Yes 30lbs....ill try adj fp never done it before but ill check tgo....not sure what ecu i have i pretty sure its a 305 ecu...po swaped the 350....i think its aujp ...more learning it looks like

I dont think ill be able to do my tuning ive seen the tech article on this...any reccomendations on tuned sites or doing ur own???

 

https://www.thirdgen.org/forums/diy-...uide-book.html
Chapter #5

If Your needing assistance send me a pm , You will need to data log but. Most people are using tunerpro.

http://www.tunerpro.net/
http://www.aldlcable.com/

 

^^^reading thru now thanks!!!!!!!!!!!

 

Don't waste your time until you get a custom tune.
30lb injectors with a stock tune for the 22lb units is going to be outside of any adjustment you can reasonably do on fuel pressure alone
if you drop the FP too low the injectors won't spray right.

Even worse it it still has a 305 memcal in it which is tuned for 19lb injectors

FWIW.
The ECM turns the fuel injector on for a set time based on what size it thinks it has , based on the info in the tune.

Like you with a 3/4" garden hose , if you turn it on for 1 min you get X gal of water out.
What happens if you have a 3" hose turned on for the same amount of time ?

 

^^^^makes sense and vetteoz thanks as always ill have to wait for a tune...was excited to get it started just didn't want to believe the truth and have to tune so soon

 

Got some stock injectors to throw back in it temporarily?
Only a 30 min injector swap job on a HSR to at least let you run it

 

For a 350, about as much injector as you're every likely to need, is the Frod light blue top 24 lb/hr ones.

Smaller injectors and high FP is nearly always better than too-big ones and low FP. Common n00b mistake.

If lowering the FP helps, you know IMMEDIATELY that you've got too much fuel.

 

my stock injectors didn't sit low enough and as a result my hsr fuel rails didn't fit against intake....but just want to verify its ok to bump down fp until I get a tune???

ah didn't know 24 lbs was sufficient...seems like I always read bigger injectors you can always bump down...grrrrrr

ill be speaking with tuned for some help and post back when running better (hopefully soon)

thanks guys!!!!!!!

 

That's true, to a point: subject to, if you "bump down" by lowering the fuel pressure then instead of getting a spray you get a dribble; and, in order to "bump down" by reducing the duty cycle, you have to do some electronic programming; and, even I you "bump down by way of programming, there's a limit to how short you can make any real-world injector's duty cycle at light load (idle & slow cruise), such that it becomes nearly impossible to tune down there where your street engine will be spending 95% or more of its life.

Better all the way around to pick an injector size that doesn't require so much of this "bump down", so you can run high fuel pressure, it isn't quite so sensitive to programming, and it's more controllable at the low end of the spectrum of power outputs that it will have to live in.

Given that you can pick up a set of those light-blue tops for like $40 a set and soak em in thinner (not perfect, but adequate for the purpose at hand) for a coupla days and put new O-rings on em and run em, and turn around and sell em if ya don't like em, whaddya got to lose?

 

IMO doing a tune off of adjusting fuel pressure is not the best way of doing things. In this case since the injectors will work fine but the tune is really messed up as even a starting point start and leave fuel pressure at 43.5 with the regulator vacuum line disconnected and plugged. Like vette oz mentioned if the memcal was from a 305 that will make the engine run even worse. Once the injector size is set in the programing and a more aggressive spark curve is used the fine tuning can take place.

 

Cant thank you all enough....so ill leave my fp alone until i see about tuning...i do have spare yellow top fords that are 19 lbs i believe from my 93 f150....maybe get it running better till tuning is complete appreciate the help

 

The memcal You texted me the letters of the broadcast code AXYB acdelco /gm part 16163137. This is a 305 speed density memcal with a manual transmission ;(
No wonder this thing is running so so rich.

 

pm sent....not sure how this has affected the 350 that was in it before the upgrades...im guessing I should feel a bit more kick after the upgrades and correct ecu

 

The butt Dyno is going to go off the chart lol , no seriously If the previous owner had 22-24#hr injectors in the 350 it was running rich all the time robbing hp and washing down the cylinder walls. If they had the 19 injectors from the 305 the 350 would run hot and lean either way not a good combination. I just sent you a pm about a Aujp I have gm 16151348
That would have the correct knock esc module for a 350. A corvette tune with the correct injector flow setting would be a great start but there could be room for improvement thats were data logging comes in. A wide band gauge helps alot but alot can be done bye watching a few data logs in closed loop with the engine warm slow and steady accelerations upto high way speed.

 

sounds like your almost ready for your first spin

 

update****

just to confirm the original problem and fix:

it was the tune that was needed....

thanks to everyones help especially brian @ tunedperformance....im currently speaking with him on fine tuning this street machine...I will be commenting on his vendor thread but quickly need to say this guy is awesome!!! knows his stuff and extremely helpful and nice...and honest!!!!...will save more raving on his vendor thread but had to say

that being said.....took it out the garage today....and all I can say is WOW!!!! drove only through the neighborhood bc I realized I need to take care of exhaust leak and idle but amazing!!!

 

Brian is awesome. Always willing to help, and yes he is a wealth of knowlegde. Has helped us out MANY times!

Brian!!