pcmhacking.net

OK, here's a great little request from a mate who is asking me if I can Delco his 300ci straight 6 F100 on petrol/LPG.
He's been looking for one of these with control box but hasn't found one.
In the early to late 80s,some yank and jap stuff had ecu control (inc the gm c3 carby, that was controlled by the gm c3 ecu...sound familiar?) on their carbys. SOME even had o2 sensor for close loop cruise.yes, that's with a carby. Some models we got here that had this were certain camrys. The Camry system was simple, hose going from top of carby/ air filter to underneath the throttle plate with an ecu controlled high frequency bypass valve which ,when the car was cruising on the highway , predictably the ecu would read o2sensor and actuate bypass valve to lean out the intake stream or not to create a close loop mode for the engine..under the carby.(incedently Nissan h20 ,mitz colt ,4g63 ,2l escort carbies and more used a similar system for deceleration enleanment albeit vacuum actuated)
Knowing the c3 ecu aka delco used to do it anyway, my feature request for a spark only tune is (if it can be done...can it?)

To use ..the(wideband/narrowband) o2 data to actuate the IAC , which will be installed in its own little manifold and piped between the airfilter and underneath the throttle plate .
Is this possible to do in a bin?
I've also thought about undesirable leaning on a straight six and will probably install the o2 sensor at the bottom of no6 ex runner to make sure cyls no 2-5 will be richer.
The handy part of this mod is the bore size is almost the same as a 304, so a hsv knockboard could be used!
Anyone interested?

The yank stuff was for catalytic convertor equipped carb cars cause a convertor needs the fueling to swing rich then lean then rich like closed loop fueling to feed the convertor enough oxygen to burn the bad stuff some had an air inlet on the convertor as well to feed in fresh air to burn

I'm aware there's a spare pwm out on the 12p, and I'm happy to mod it, I just don't know how to chain it to an injector line and only step the IAC when under the right rev range/speed/load so it will correct a rich exhaust.
I know 16 bit address space,rough 8bit architecture and counting in hex, just not the OS well enough...iirc there's a spare customisable algorithm in the tune last time I looked at it, but can I use that to drive a stepper witha pwm out...hmm maybe I should double check. Apart from that idk
If its possible, can someone point me in the right direction?

That's interesting! The first car I knew of with an 02 sensor I came across in my readings was a 1.9 (yes, a holden Opel moonchook engine) carbied Opel rekord D '76 which had a glasshouse suspiciously lh-uc Torana like...
I the cat needing o2 is news to me, makes total sense.

Sorrite I rftm'd again. Course its possible.
Especially with a pwm board and a ford 7200vv carby.
Thought it sounded familiar.
Or I could use a carbon canister solenoid.

delcowizzid wrote:The yank stuff was for catalytic convertor equipped carb cars cause a convertor needs the fueling to swing rich then lean then rich like closed loop fueling to feed the convertor enough oxygen to burn the bad stuff some had an air inlet on the convertor as well to feed in fresh air to burn

Yes thats right, Antus, the associated hardware (with Mitz carby engines )is called a secondary air system , which does exactly that, its air 'supply' pipe is tuned length.
the other system that also allows additional freshair on decelleration enleanment(with a minuki carby) is called the "mixture control valve".
so this function is available on mitsubishi carby cars.

Just a thought on the narrowband to control AFR, You wouldn't need the delco to do this, just choose a PWM air bypass valve and a simple analog, or digital circuit to read the o2 voltage and adjust pwm accordingly. I'd use opamps and maybe a 555 to do it, or you can go the arduino route.

There's also an open source delco 808 project that you could code in what you wanted. It's coded in C which is a lot easier for most than asm though it is not developed anywhere near like what 11 or 12p is.