Why Programmed Fuel Injection

[mgardner]

Is there a specific reason that they call it programmed fuel injection? Don't all electronic fuel injection systems use some type of program to determine the proper amount of fuel flow into the engine? Just wondering.

-Mark

[Vanilla Sky]

no, not all of them do. some are more simple systems, more like mechanical, but with less in the way of controlability. that's really what set our cars apart from the domestics of the day. our cars can readily adapt to any and all conditions, whereas something produced by dodge in the same era is more akin to the megasquirt system that has become popular for some odd reason.

[pmpete]

PGM FI is a sequential port fuel injection system. It was way ahead of its time most makers at that time were using throttle body ( one huge injector to replace the carb). Other that did have multi port only squirted fuel at whatever rate the ecu felt it need to provide enough fuel and it fired them all at the same time. Sequential started showing up on other makers 5 or so years later meaning the injectors only fire at the moment the valve is open. This minimizes "pooling" on the intake valves. Also the 88-89 model feature the dual mode intake system that was "discovered" by other makers up to 10 years later.
Paul

[mgardner]

Also the 88-89 model feature the dual mode intake system that was "discovered" by other makers up to 10 years later.
Paul

What does that mean? Are you referring to the secondary butterfly valves? I don't know much about these cars, as this is my first and I only aquired it about 9 months ago.

[HondaBoy]

i think that was what he was talking about. my instructor in college explained the different fuel injection systems a few weeks ago. i think the reason for the "mega squirt" type thing was popular was because it was cheap and easy. just not so great for optimum fuel mileage. my '76 datsun 280Z has a pretty advanced fi system in it for its day. multiport with computer control. dont really know how its all works, maybe some what the same as the programed that honda has, but surely not as advanced. doesnt really adapt to climate change like pgm-fi does.

[pmpete]

The dual mode intake butterfly valves work like this. Below 3500 rpm it closes off half of the intake passages. So the engine is restriced to breathing through half of its valves. The purpose of this it to keep the velocity of the air high. This turbulence creates better mixing of air and injected fuel for smoother burning and more torque at low speeds. That is why the LXi's are so good in the driveabilty department. Above 3500 you will can usually feel the transition as the engine is allowed to breathe at its full capacity.
Paul

[AccordEpicenter]

if it wasnt programmed fuel injection, itd run like a ford:barf:

[speedpenguin]

i think the reason for the "mega squirt" type thing was popular was because it was cheap and easy. just not so great for optimum fuel mileage.
Mega Squirt is popular because the program is free. At least that's what I think. I would only use it if I was trying to convert a carbureted car over that I couldn't swap an EFI system from another car into.

[mgardner]

if it wasnt programmed fuel injection, itd run like a ford:barf:

Yea, I got an '87 Bronco II that's fuel injected. It makes me want to convert it to carbureted, because I've been having nothing but trouble out of it lately.

-Mark

[Mars]

The dual mode intake butterfly valves work like this. Below 3500 rpm it closes off half of the intake passages. So the engine is restriced to breathing through half of its valves. The purpose of this it to keep the velocity of the air high. This turbulence creates better mixing of air and injected fuel for smoother burning and more torque at low speeds. That is why the LXi's are so good in the driveabilty department. Above 3500 you will can usually feel the transition as the engine is allowed to breathe at its full capacity.
Paul

Were these engines kind of a precurser to vtec?

[pmpete]

This was used on later version of the F22 in the 4G Accords. Got tossed on the VTEC F22s and F23's that showed up on the 6G. The 6G F23 is a sweet motor. I own one I should know. VTEC is really a lot more complicated though. It basically allows you to have completely different Cams for low speed and high speed operation of the engine.
If you ever get the change to drive one of the New Civic Si's do it the VTEC in those is mindblowing for the amount of performance boot they have when it kicks in.
Now if I could get my hands on one of those K20s and give my accord a transplant that would be something amazing.
Paul

[HostileJava]

Got tossed on the VTEC F22s and F23's that showed up on the 6G. The 6G F23 is a sweet motor. I own one I should know. VTEC is really a lot more complicated though. It basically allows you to have completely different Cams for low speed and high speed operation of the engine.

Paul

Maybe I"m missing somthing, but the F23 Vtec in my van hasn't impressed me much. Other then the fact that I can rape older civics in my van anyway. Is it a different engine then what's in the 6G accords? I believe mine is an F23A7

[pmpete]

In a much lighter Accord its a blast. Speaking of dusting Civics with an Odyssey, I love doing it with my 06 with its 3.5VCM. Now thats power! Never thought a Mini Van could haul ass like that. What is really cool it the way it switches to 3cyl when cruising, can hardly notice it.
Paul

[HostileJava]

In a much lighter Accord its a blast. Speaking of dusting Civics with an Odyssey, I love doing it with my 06 with its 3.5VCM. Now thats power! Never thought a Mini Van could haul ass like that. What is really cool it the way it switches to 3cyl when cruising, can hardly notice it.
Paul

I was under the impression that the accord wasn't that much lighter? I think my van weighs in at around 3500 lbs.

Edit: Now that I think about it, the 6G is probably closer to 3000 lbs.

[pmpete]

Yes you are correct a 6G 4cyl weighs in at about 3000 lbs. 500 pounds makes a big difference. One thing you do have going for you is the Ody has shorter gearing to comp for the weight.
Paul

[pmpete]

Speaking of weight problems, the 06 Ody tips the scales at 4600 lbs amazing how that motor can move that oink.
Paul

[AccordEpicenter]

it is a hell of a load on that little motor. Early ody's use F22s from accords. If you ever do an engine swap in accord, dont put an ody motor in it, that big load takes its toll on the motor, even though an F22 is hella stout already, kinda like A20

[pmpete]

Good point on the F22s being in the early Odys. The F23 with VTEC was a lot better set up but still close to its limit. Just stay away from the early F22s they had major problems with the rear main seal.
Paul

[mgardner]

Another thing that I read on other threads is that our ECMs are non-chippable or unchippable and stuff like that. Why is that? No one ever really gave an explanation as to why they arn't chippable, they just said that they weren't.

-Mark

[AccordEpicenter]

they dont control ignition timing (chipping a PJO therefore=pointless). There are ways of chipping them but its not like you think and its way way different than chipping say, a P28 ecu