Outer Limits 4x4 Board

Does it matter anyway?

Yes at last I have got my Nissan P40 engine converted from carb to fuel injection. Although I am still in the tuning stage the results so far are impressive. Lots more torque and power and it idles happily on a 45deg slope which was the main reason why I started the conversion. Previously it tended to flood on steep hills which is not much help when winching and your plugs slowly oil up. Took it for a tuning/test run down 60 km of river bed over the weekend (max depth of fords about 60cm) and I found that previously where I had been using 2nd lo I now used 3rd or even 4th. Nearly got stuck in loose pea gravel a couple of times, I was on my road tyres, 32" ATs, but the extra power pulled us through. Should have no trouble turning our Simexes. Some of this power & torque improvement results from new extractors I had made to replace a warped exhaust manifold, but even before I fitted the extractors we powered up a steep fire break where previously we used to struggle.

System is,


Megasquirt ecu
Falcon EA throttle body (TB) (similar 4L straight 6 engine)
Megasquirt relay board
Coolant sensor (CLT) in thermostat housing
Manifold air temp sensor (MAT) in inlet manifold
Manifold air pressure (MAP) sensor in megasquirt ecu connected to manifold vacuum take-off
Wideband O2 sensor in exhaust with LC-1 controller
Throttle position sensor (TPS) incorporated in EA TB along with fuel pressure regulator
Bosch HP fuel pump fed from a 2L surge tank which is fed from original mechanical pump
Missan inlet manifold modified to take Falcon manifold plate and tapped for MAT sensor
Air filter modified from a GQ

Ignition at present is conventional Pertronix ignitor and dizzy but as soon as we have the fuel sussed out we will convert to Megasquirt controlled ignition using the signal from the Pertronix.


Picture of installation below. And yes this is a LHD truck.



and another with the filter box removed




We still have a lot to learn especially about tuning, but hey, 12 months ago I knew nothing about efi and now I have a working system.

David

AWESOME!!

I am just researching a similar project for my 253 Holden motor.
Am looking at an almost identical setup with falcon throttlebody and megasquirt to run it all.

Did you build the megasquirt yourself?
How did you go getting a basic tune and is the megasquirt simple enough to work out for basic tuning?
I am in the roughly the same boat as you, never played with EFI before so everything is new to me.

Seeing this has given me a big bit of reassurance to give it a go.

Thanks
Leeham

leehamescort wrote: Did you build the megasquirt yourself?
How did you go getting a basic tune and is the megasquirt simple enough to work out for basic tuning?
I am in the roughly the same boat as you, never played with EFI before so everything is new to me.

Seeing this has given me a big bit of reassurance to give it a go.

Yes, we built the megasquirt ecu, relay board and stimulator board (for testing the ecu during construction) from kits imported from the US. You can just buy the printed circuit board and then source the components locally but you don't save much and waste a lot of time. For assembly you need basic soldering skills and the ability to follow instructions. A solder station such as sold by Dick Smith is almost a must. I cheated and got one of my sons to assemble it for me. Megasquirt is very much DIY so you have to work things out yourself sometimes particularly with the various ignition options - dizzy, EDIS etc but there is alot of help on the megasquirt site and in the megasquirt forums.

Megasquirt is actually quite a sophisticated ecu with all sorts of features most of which you don't use initially. Basic tuning consists of setting up the base parameters for your particular engine and injectors using the free Megatune software - eg simultaneous or alternating firing, warm-up enrichment, and the VE table etc. and then getting the truck to fire up and idle right. Once that is done you head off down the road with your laptop plugged in and adjust the various "bins" in the VE table to get the appropriate AFR (air/fuel ratio) for the various combinations of rpm and MAP. It is recommended you have a co-pilot do this if you don't want to write your truck off prematurely!(':P')

You can datalog all your your readings over a period as an xls file and view them later with Megalog Viewer which will analyse your VE table and suggest changes. All this assumes you have a wideband oxygen sensor which will give you your actual AFR whereas a narrow band O2 sensor will only tell you whether you are richer or leaner than the stoichiometric AFR of 14.7. Wideband sensors and controllers are not cheap but you would soon be lost without one. Then when you have a good VE table you can move on to acceleration enrichment etc. and closed loop AFR control. This is the point we are at.

You don't understand it all at once but the more you get into it the clearer it becomes. Well, sort of!!

With the hardware installation it pays to plan carefully and make and keep drawings updated as you go, particularly the wiring diagrams. Megasquirt can control both spark and fuel but I suggest you try one or the other first not both together. We tried both together but had timing problems so are getting the fuel right first.

If you want to read a good introduction to how efi works I have the Technician Notes for the EA Falcon in pdf format. PM me for a copy.

David

got any Links to were you purchased your Mega squirt from?

There is a list of suppliers at

http://www.megasquirt.info/

See FAQ No 7

I got mine from SparkandFuel at

http://www.sparkandfuel.com

and got good friendly service from Gary. He supplied me with kits for the Megasquirt II v3, the Relay Board and the Stimulator Board. He also supplied an LC-1 wideband O2 Controller.

David