i know this topic has been beat to death but i need help and i dont have time to search. i have an 86 305 tpi with headers dual flows,ads chip, bigmouth intake,255 ltr holley fuel pump, summit cam 420/442 lift and 202/212 duration no emission stuff, and bored tb, plennum and runners. my stock injectors are cracked and the end fell off one of them. i already have 24#injectors not going to buy more. would it be fine to put them on and turn the fuel pressure down, well i am going to put them on but will turning the pressure down help and to what pressure should i put it at?

 

Turning the FP down will help but you will really need to change your PROM to compensate for them, especially since you have the stock 19#ers now. Are they Accel injectors?

 

I have had my accel 24# injectors on my stock 305 TPI for over a year and no problems. Stock Prom too.

 

You dont have time to search but you have time to site down and write this post ? THat's stupid !

 

Didn't you answer your own question? You are not going to buy any more b/c you already have 24s? If i were you i would get at the most 22s, but then again your not buying any more! Put them in and burn a chip, atleast.

 

Your gas mileage almost surely dropped because you are running rich. You may not notice it (not sure if you track your mileage or not) but you WILL be better off by getting a new chip. Your injectors are pumping in MORE than 25% more fuel than your computer is aware of.

 

When I first got my car I got about 9mpg. I replaced my intake gasket and saw that my injectors were all cracked so I got new ones. I decided to go with 24# because I thought that would give me more power. I didn't know too much about thirdgens then.
I now get around 15mpg so that is definately an improvement. Plus my scan tool goes Lean...Rich...Lean...Rich.

 

I can assure you that with your setup you are not making more power with those injectors vs. good, working stock ones. You would be better off getting a new PROM though since you have already installed the injectors.

 

Hmm, 15mpg out of a EFI 305 - Thats pretty Pitiful.

Danny is dead Right. Garunteed your BLMS are pegged at 108 In Closed Loop All day Long.

Thats Not Running "fine" By any means.

You really need An injector constant change in the PROM at least - And I know just the guy to do it lol

 

the 24#"s are off an 89 mustang.

 

i am in the military and i just now was able to get back on the computer, so its not that stupid

 

24# is way too much fuel for a 305 generally, there may be wild buildup exceptions but yours doesn't sound too extreme.

To get to 19# you'd have to drop the fuel pressure way below the spec limits of the injectors, resulting in a dribbly spray instead of a nice atomized cone. That's assuming your regulator goes down low enough, my Holley with my fuel pump mins out at 38-39psi. At 39psi your injectors are delivering ~24#.

So...you have two easy options: jump on EBay and snag a set of yellow-top Ford 19# injectors for cheap (not very high demand for these) or have a chip burned to reflect the 24# injectors and see if the engine is happy that way. I'd go the first route, seen Ford 19# injectors go for $50 and you can sell your 24# to offset the cost.

 

Ok so Bort.. Do you do them and how much do you charge??(Burn chips)
Kevin.. should I set my PSI at 39 for the time being?

 

double-post

 

You should adjust it to whatever it takes to make your engine happy. BLMs in the 128 range are a good indicator.

 

Link In my sig should Cover it... Don't really wanna use TGO as an advertising medium

 

A 1988 GM EPROM for a 350 and your gearing should get you a lot closer with it's 22# inector constant than the 305 chip with an 18# injector constant. It still will probably run rich regardless, just less rich. You might be able to "tune" the idle by gutting the MAF sensor (if you haven't already). Anything and everything you can do to get more air into the engine (since you'll be putting more fuel in) is critical. Anyway,,, the EPROM from your local GM dealer should run around $45. Depending on how tight (or not) your money is,, it might be worth a shot.

 

Or you could spend the Same amount of Money, And Do it Right.

 

Sorry,,, not trying to take money out of your mouth - just a quick and easy option.

 

It's not about that - Its about this guys car Running Right.

What you suggested is Not really a Viable Option - thats all.

replacing one wrong part with another.

 

Not a viable option? Viable - Likely to "live", at the stage of developement where its likely to "live".

The $40 bucks you charge for burning a chip does not include modifying the EPROM to accept the chip. So you either have to be skilled with a soldering gun or buy one of the Moates adapters, or find a custom JET chip going on Ebay to use your chip - which I'm not knocking any of these things.

All I'm saying if the dude doesn't want the hassle (how little it may be), he could go to the local GM dealer and get a chip that would more than likely work better than what he has now. Right, wrong, or indiferent, it's an option.

 

Good points -

But I wouldnt recommend it. There are other differances between the 305 and 350 Bins beyond injector Constants - Where he is closer on some things he is gonna be farther on others.

I personally don't think it would serve him any great benifit, But thats Just my semi-educated opinion - either get a Chip thats Right, or leave it how it is.

 

Oh I will Add some evidence.

A member of this forum sent me a log from his Car Using 24# Injectors on a stock 305 Bin. It is ontop of a pretty pumped engine.

His BLM's were at 108 across the board. So if you think that the injectors arent causing you to be rich - Don't be so sure.

Im burning him a chip that sets the Constant right, and then we will likely take another scan and go from there. IMO a better option than band-aiding it.

But Do what you like, it is your car, after all.

 

this may sound stupid but what is BML? im guessing its the air fuel ratio on the dyno, maybe

 

You're right.

 

BLM = Block Learn Mode

Also known as LTFT or Long Term Fuel Trim. A good indicator of how much fuel the computer is adding or subtracting in order to keep the AF optimal. i.e. running rich or lean.

Just do a se... nevermind.

 

HAHAHAH That is freaking funny. That is the exact reason why I dont post here that much. All you have to do is learn how to search and be creative with the words you search with and you can answer every question that you will ever have. Well almost but for any starter you will answer every question.

 

Exactly - Why Do you think I havent posted a question on here in over a year ?

Not because I know everything....

 

I have 24# injectors and the fuel pressure at 48lbs and my car still runs rather lean. The fuel pump is pretty new too.

Last time it was dyno'd, they hooked up the stoich fuel meter and it ran around 15.00- which is lean.

 

Formul8.. This is Crazy3rdGen from MfBa. Do you have a chip for the injectors or no?
Also do you know a lot about 700r-4's?

 

I'm still running stock chip. That may be the problem.

Also, the ONLY advice about 700R4's I will give you is to have FLP in Naperville build you a new one. I have one in my car and it kicks ***.

 

Are you running Accel/Ford SVO injectors?
If so: At 48psi they are flowing 26.46lbs/hr. That seems like quite a bit of fuel for the mods you have.

 

I am running ADS matched injectors. The car runs great, I have the timing at 10 degrees, and no explanation other than the car loves the way it is tuned. No miss, no knock, no detenation.

I have owned this car for 9 years and have tweaked it little by little.

 

Do you know at what PSI the ADS injectors are rated at?

 

Running a WB-02 Behind a Functioning Cataletic Converter will Do funny things like that.

I have YET to see a car Running Larger Than Stock Injectors on a Stock Chip that is not setting at 108 BLM At part throttle.

WOT you might be a little closer - but thats a differant story.

 

I like to piggyback a question on here, I'm debating puting Holley or Accel 24# inj on my '89 that I'm rebuilding.
I looked in Jegs and such and noticed that the Accel's are much cheaper but do they last?
I read one good commet so far in this thread - any other comments?