possible injector problem 4.6 stroker

[turbobaja1835]

I have recently built a 4.6 liter stroker for my 92 xj and I love the motor but at the current time I have the stock injectors in it still because I can't seem to track down a set of ford 24 lb. injectors for the price i want to pay. My motor bogs down on up hill climbs on the street if I step on it and the only thing I can figure it is, is the stock injectors. I think it may be bogging down due to the lack of fuel they are putting out. I am wondering who out there has had a similar problem or might have some input on the situation???

Thanks, Joe

 

[turbobaja1835]

I have recently built a 4.6 liter stroker for my 92 xj and I love the motor but at the current time I have the stock injectors in it still because I can't seem to track down a set of ford 24 lb. injectors for the price i want to pay. My motor bogs down on up hill climbs on the street if I step on it and the only thing I can figure it is, is the stock injectors. I think it may be bogging down due to the lack of fuel they are putting out. I am wondering who out there has had a similar problem or might have some input on the situation???

Thanks, Joe

 

[wascobi]

did you check out www.fiveomotorsport.com ?

 

[Eagle]

Bob Salemi (who posts on here as just "Bob" when he's around) had that problem when he first installed his stroker. Being a tinkerer type, he already had an adjustable MAP sensor and he used that to fool the computer into enrichening the mixture, and that was able to smooth out the flat spots and bog. He then tried a set of 30# injectors and found they were too rich. He has finally found an injector that's fairly close to "right" and runs well -- unfortunately, I don't remember what the rating was. I think it was 26# but I am not certain.

I know he did a write-up, but I don't recall if it was posted here or on the Strokers' discussion group at Yahoo.

 

[Bones]

I run a 4.6 with 30lb injectors. According to the Air/Fuel gauge, I am running a bit on the rich side. I plan an adjustable MAP sensor set up soon for some fine-tuning.
I will probably still leave things a bit on the rich side, as I would rather spend extra on gas than a new motor.

The cheapest way to buy a set of injectors is to watch eBay or call Mike at Accurate.

I would guess 26 lb Injectors would be close to ideal, but I'd still rater choke down 30's than to try and over clock 24’s or 26's if they ran to the lean side.

Bones :skull1:

 

[M. Lake]

Changing to an adjustable FPR off a '96 or newer 4.0 will change the fuel flow rate per hr. I don't know how the #s are exactly, but Dino might. In which it will richen up the injectors.

 

[Dr. Dyno]

The '96-'99 4.0 injectors flow 23.3lb/hr @ 49psi while the '00 and later injectors flow 22.5lb/hr. These flow rates aren't enough for a stroker so you'd definitely need a MAP adjuster. The MAP input voltage will need to be higher than the stock 5.0v to prolong the injector duty cycle and richen the A/F mixture. Remember that there are limits to how far you can go and once you've reached a 100% injector duty cycle, you can't richen any further. If you reach an injector duty cycle of 90% or higher, it's safer to replace them with bigger units.
The '96 and later 4.0's have an in-tank regulator so an adjustable regulator really isn't an option. It IS an option on the earlier 4.0's though so you could crank up the fuel pressure above the stock 39psi to increase fuel flow through the stock injectors. The increase in fuel flow is proportional to the square root of the fuel pressure, so an increase in fuel pressure from 39 to 44psi would produce a 6.2% increase in fuel flow.

 

[M. Lake]

Thanks Dino

 

[sjx40250]

Adjustable Fuel Regulator

The '96 and later 4.0's have an in-tank regulator so an adjustable regulator really isn't an option. It IS an option on the earlier 4.0's though so you could crank up the fuel pressure above the stock 39psi to increase fuel flow through the stock injectors. The increase in fuel flow is proportional to the square root of the fuel pressure, so an increase in fuel pressure from 39 to 44psi would produce a 6.2% increase in fuel flow.[/QUOTE]


Dr D where would I find an adjustable regulatror?

 

[Bones]

Dr D where would I find an adjustable regulatror?

HESCO sells an adjustable fuel pressure regulator on their site. Like everything else at HESCO, it's about 2x what it should cost though.

I do not believe everything that HESCO spews as gospel but they do make some quality stuff. I run a HESCO water pump and looked into the AFPR when I did my stroker.

Bones :skull1:


HESCO catalog

 

[rsalemi]

Adjustable regulator $3

[Look at the Hesco website - www.hescosc.com) - and make your own - tap the inside of the vacumn port, insert roll pin and allen set screw (with flat ground on one side to allow vac to work) and crank up the pressure (carefully - don't split the diaphram) . I showed 14 HP gain on a stock 4.0 going from 39 to 48 lbs - works same on stroker - I'm running 24.6 injectors at 45 lbs giving 26.7 lbs and a 13.5 AF ratio.