ECm for a car??? please help me

I am new to this site, and am glad i found it. I have a 93 Plymouth Sundanace that i plan on creating a fuel management system for, I know of a website where a guy used a circuit board to build an extra injector system that would turn on based on voltage reading from one of the engine sensors... Basically i wanted to know if any one could look at the diagram on the site, read a bit of the info and let me know how that should be done, the parts i would need and if i could get them easily... I know im asking alot but i would really like to know how its done, and i couldnt get ahold of the guy that runs the site...

thanks
Dustinicus

I don't think you understand the complexity of an ECU?, it's a highly complex system designed and programmed for specific vehicles.

I am sure that there are many people here who would help and encourage you, or on the other hand rip the idea to shreds!
But first you have to tell us which website has the info on the fuel injector system.

JimB

http://www.turbodiy.com/Mopar Pages/twin_turbo_89_shadow_detail.htm
-thats the one for the main page that the link is on...
http://www.turbodiy.com/Mopar Pages/extra injectors control detail.htm
-that has a general discription of whats going on....
http://www.turbodiy.com/Mopar Pages/schematic detail.htm
-that is the circuit shematic for the board...

I know that its just for the extra injectors, but I was more over wondering if i might be able to have some kinda of rising rate voltage regulator that increases volts or ohms or watts, wich ever one increases how much output the injectors give, then hook it into the extra injectors and find out what i should set the volts at (based on an ohm meter and my air/fuel ratio gague) and everyhting at while its running, then set it up to kick in more juice when it starts to go lean on me...

Another idea is to build an on off system to run a different injector system to switch between the two at idle, and kick em both on once the rpm's get high enough... mabye even an advancer on the distributor timing so it will advance it early right when the car kicks on both injectors... Anyway thanks for any help I can get, and i think just figuring out that circuit board will help me to build just the setup that they have running, and figure out other little things with some more research and help here...

hope i didnt loose you,
Dustinicus

How about including a link to the site?

Just talking about it isn't much good.

I posted links, but i guess they didnt show up, how do i do that? or is anyone willing to let me email the links to them please?

-Dustinicus

the extra injector's ar normally only used on boosted car's and are run from a pressure sensor in the boost pipe, higher boost + more fuel = more power.

The injectors are pulse width modulated, so a longer pulse = more fuel.

one side of each injector is connected to igition + (12v), and the other is grounded via the ecu, to provide the opening pulses.

adding an extra injector is easy, with sensors readily available, and the most basic pic processor capable of doing the conversion from voltage to pwm and can also add some safety features with the spare pins.

if your serious about building your own ecu, i suggest that you visit www.megasquirt.info, build one of there ecus and learn how it all works, and then (if you successfully get your car running on the megasquirt), proceed to building something of your own with the features you need.

be prepared to buy new injectors along the way, as they are different impedence between different cars, and can be damaged by wrong wiring.

and if you screw up, and run lean, its gonna blow your engine too. not trying to put you off, just want you to realise how big a job this is.

I understand that i could really f my world up if i do something wrong i got an air/fuel gague for this reason, adn as for the pulse width i know of the impedence and all that, i just wonder if there are resistors and such that could read engine speed and automatically adjust pulse width to where the rpm is.. but i guess that would take a REALLY big circuit board with alot of stuff that a megasquirt would cover.. ive looked at the megasquirt, but when i asked them about it they wanted me to buy a munch of stuff im not so sure that i would need for my car right away, all i want is fuel management, and they are talking spark control new sensors, do you know anything more that i might not? i guesss im kinda lost... sorry to have bothered anyone...

ok im back again... I was wondering you said that the extra injectors read boost and that help to decide when more fuel is needed couldnt it work the other way and read vaccume, and when the car is at WOT (WideOpenThrottle) there wouldnt be any vaccume and when its idling it would read nothing but vaccume, so could a guy make something so when it reads full vaccume the fuel is normal, and when its reading no vaccume to have the extra fuel, i can adjust what ever might be nedded to adjust i just kinda was wondering about any kinda crude but effective method to wire up my current injector system... (I am using a single injector ECM and making it run 4 injectors at once in batch fire mode)
How about an electronic switch system that will rotate between 2 different injectors... example being: every time the signal is sent to fire what the ECM thinks is 1 injector, instead it only fires 2, then the next time it gets the signal it fires the other 2??? could that work? and would it be very hard to make somthing like that? I know i am asking alot and i really am hoping that i will be able to get something off the ground.. I am not talking about building a completely different fuel system, I'm talking about using the stock system, and making some "adjustments" to run 4 injectors instead of the crappy 1 TBi style that has no breathing room and sucks balls... besides, i plan on turbocharging in the future, I like custom stuff, and this car is a life long project (ive had it since i was 14 when my dad gave it too me) so i really wanna do alot, but ide like to be able to say when some one asks "howd you get that to work?" or "what the hell is that?" i just wanna be able to say yeah it was some work but I did it with NO BODY else.. satisfaction..

thanks again for all the help i can get...

BTW did any one look at those links i put on an earlier post... they would be kinda helpfull with the extra injector system and all and my trying to make some (sorta).. Did the links even work?

right so im guessing from the post above that your car isn't turbo'd or supercharged, - so... does the car have a catalytic convertor, or lamda sensor, (the one in the exhaust pipe) cos if it does, then your fighting a losing battle. the ecu is factory programmed to produce a particular mix of air and fuel. When you inject more fuel yourself, which the ecu isn't aware of - it will notice it in the exhaust, and back off the standard injectors to compensate. Only way round this is to either build a pretty complex board (approaching megasquirt level of complexity) and piggy back it onto your existing ecu, or fool the sensors by modifying the inputs ect to the ecu.

My personal view is this, if you JUST want more fuel (why i do not know, as it will run rich and loose power, unless theres more air to go with it), the you should unplug your air temp sensor from the intake pipe (or wherever it is on your car) and replace it with a pot (value will depend on your particular vehicle) by running a pot from the loom that used to go to the temp sensor, to a pot mounted in the car. what your doing now is fooling the car into thinking its colder outside than it really is, at which point the ecu will lengthen the pulseses to the injectors giving you more fuel. combined with your a/f meter you can dial-in your desired fuel (up to a point) till you get to the stichometric spot (14:1 or there abouts i think).

hope this helps, and you did ask if you could get a resistor to cause more fuel to inject, by adding it on the air temp sensor wires, thats exactly what you'll be doing.

dont blow up your engine!!!

I think he wants to drive down the street with black smoke coming out of the exhaust. The catalytic converter will get extremely hot trying to burn it and the engine will have hardly any power.

If he fiddles with the turbo's boost sensor so it boosts the boost, it will need more fuel which is where adding injectors comes in. A good way to blow up the old engine.

What is your goal here? Are you trying to make the car more powerful, more fuel efficient, work with a turbocharger or some other modification, or run on an alternative fuel or what?

More fuel doesn't in itself mean more power. In most cases the injectors are sized so there's no limitation on getting fuel into the engine.

I know how air/fuel works, and i know more fuel will just make the car run rich, i dont have an air temp sensor on the car it never came with one, and it dosent have a catalytic converter, what im trying to do is make the singe injector system it has now, run the multi port intake that i have for it, the way i have it now it runs WAY too rich, and im not sure why, ive seen this mod done before and its worked fine for otehr people, they just batch fire the injectors so they all fire at once, but they way they did it was just wiring them all to the one output from the ecm...,
what i wanna do is make something that will alternate between the four injectors, and fire them 2 at a time... so the first signal would fire say injectors 1 and 3 then the second will fire 2 and 4, jsut something that will switch between the two...

What about a magnetic pickup sensors, and a toothed wheel? would something like that work, say a 1 tooth wheel and 4 sensors that make the injectors fire only when the wheel hits the coresponding sensor?
so... my theory is that i could make the sensors be directly connected to the coresponding injector, and that way it will fuel the cylinder that needs the fuel next.... but my other thing is that i would need somthing that after a certain RPM to switch them all into batch fire mode...

Hope you all follow me
Dustin

We call it a "crankshaft position sensor". Ford pickups and vans would fire 4 injectors at a time, it was called "bank firing" as opposed to individual "sequential" EFI. One injector replacing the carb is called "throttle body fuel injection".

Any attempt to run an EFI without a number of sensors will run into problems, the fundamental nature of the problem is that the amount of fuel needed per cycle changes based on a number of factors. Without some basic sensors it won't just be less accurate or a bit less mpg than it could be, rather it could overheat the cat, foul the engine with carbon, flood, backfire, or stall often. And get terrible emissions.

Yeah you really need to look at projects like MegaSquirt and others. They seem to know how to do it right.