i have already installed 19lb injectors in my 91 3.1 and i need to know what all i need to mod to compensate.i am not going to go back,i am only going forward.i already have a stainless 3" magnaflow catback and cat adapted at the y,and a 3"pvc cold air intake.at this point i have already replaced lots of sensors,and lots of other parts.i just want it to work and work right.

 

well to be honest with you, you went about this the tottaly wrong way, with that exaust and those injectors your gonna a ton of mods to make it work, i'd suggest going with a 3.4 and do cam heads and anything else you can afford

 

i know,it has already gone farther than i wanted to,and i will eventually do an overhaull,but right now i just need to make it work with what i have and i will get to more mods as i can afford them

 

bigger engine, cam, headers, rockers, full intake, and about everything you can throw at these engines.... Or just go with a full custom chip.


I have 3.4, rockers, headers, polished intake, stock ecm and I still ran rich with 19lbs.

 

OK,will a chip do it???if so what chip?where would i get it?what would it cost?

 

no a chip will not do it, unless you goit a custom one burnt

 

how would i have a chip burnt?i dont really know anything about chips.im just now learning engines.

 

it would be easier to just try and find someone who does it, there are a few people on the boards who do them, i'll let them chime in though, don't know if they are freelancing their services


to be honest, its gonna be cheaper to go back to the stock 15's

 

thats what I meant, a custom burnt chip, not the pos OTC ones.

 

i was just calrifying it for him dale

 

AM91 doesnt even have that big of injectors and hes about the most modded engine on here, swap back or keep em and run really rich. the only way youre gonna get enough mods to make up for that much fuel is to drop some serous $$ on parts and labor (machine work).

 

well ,ok.they are saying with intake and exhaust mods i could go with 17s.what do you guys think?

 

think it will still be a bit much.

 

what about if i put a perfomance ignition on it???

 

nope. Just some info here.

I have a 3.4, it takes 17lb injectors factory.

Mods done to it:
polished intake to flow better
debured heads (removed casting flaws)
3 angle valve job
1.6 rockers
headers
catback
modified air intake
all around oem replacement performance ignition (distrib, cap, rotor, wires, plugs, coil) Everything short of a msd-6a.

with all this, 19lb injectors are still to much for my car during normal driving ranges. Up high above 3000 or so, it helped alot. This could be fixed with my stock 17'lbs, and a re-programmed chip, and/or bump up some fuel pressure.

factory designs injectors to run at 80??% duty cycle. You can easly go up 5% with out any issues. Can also bump fuel pressure up about 3-5lbs w/o issues.

most injected cars use 14.7 parts air, to 1 part gas (14.7:1 ratio)
so you have to push some MASSIVE air thru an engine to need more gas. Ontop of everything I have, I would need a cam, and/or some ported heads to get somewhere a stock set of injectors cant be adjusted for thru pressure, or re-programmed ecm.


I'm not bashing your idea, but really, it doesnt sound like your to the point of having to justify more fuel then your stock setup cant handle at the moment. You can easly run an intake, catback, ignition. Them infact are the first things we would all recommend to you with a full tuneup/fluid flush.

 

thank you i really apreciate the solid info anyway.like i said before i am not a mechanic,im learning though.ive been doing body and paint for 10 years

 

oh and what about the msd-6a???

 

msd-6a seems to help at higher rpms, some have reported it takes longer to start the car with it.

It basically repeats half of what the stock ecm does.

paint n body? Send me some 91 light teal paint and a gm drivers front fender please