Small block EFI question

[FredZeppelin]

Hi all,

Compliments of the season.

I am preparing to fit an aftermarket EFI/CDI kit to a 2014 V7 engine that is missing most of the OEM gubbins.
I plan to fit a single throttle body and branched inlet duct.

I've got the ignition triggering figured out, I believe, but I am puzzled:
How does the OEM ECU decide when to fire each injector?
 
Many thanks in advance for any light you can shed.

Cheers

Fred

[rodekyll]

Hiya, Fred.

The ignition on a smallblock is completely random.  There's no figuring it out.  Sorry.   




Or there's a cam position sensor up front in the timing cover at about the 1:00 position as you're looking at it from the front.  It senses missing teeth on a phonic wheel that spins with the camshaft, which (among other things) times the spark.

[pete roper]

Signal is given by a missing tooth on the phonic wheel, ECU works it out from there.

[FredZeppelin]

Thanks guys for your prompt replies.

I've figured out how to time the ignition from the 48 tooth wheel on the cam nose.
There are 2 sets of 2 teeth missing, 180 degrees apart, so a gap passes the sensor every 360 degrees of crankshaft rotation.
If I fire both coils 8 degrees or so before TDC on each cylinder I'll get a wasted spark on one cylinder.
I assume that's what also happens on the OEM system, because I can't think of any other way.

However...
I can't figure out how the ECU can distinguish the induction stroke from the power stroke on each cylinder, so it can fire each injector at the right time.

What am I missing? 

[beetle]

With the current V7 MIU-G3, it uses the MAP sensor to distinguish the induction stroke.

[beetle]

I'll explain further. As the ECU sees two gaps for every revolution of the phonic wheel, it uses the MAP sensor to identify the intake stroke via the negative pressure in the intake manifold.

[FredZeppelin]

Thanks Beetle.
I'm not familiar with the new system, so I have a couple of questions:

- The manual for the previous version (2012- 2014 I think) doesn't mention a MAP sensor - is there one?

- Where is the MAP sensor mounted in the new version?

- Assuming there is a shared throttle body and a branched inlet duct, how does the new ECU decide which cylinder is producing the negative pressure detected by the MAP sensor?

The solution I'm considering is to use a separate throttle body and inlet duct on each port, with a MAP sensor in each duct and an idle stepper motor in 1 throttle body.
Not pretty.

The alternative is to remove another tooth from the tooth wheel and use that signal to control the injectors.
 
Thanks for not asking why I don't fit standard Guzzi parts. I'm beginning to wonder myself.

Cheers

[beetle]

The MAP sensor is integral to the MIUG3 ECU/throttle body assembly. All single throttle body Guzzi's have one.

The ECU calculates the piston position via the phonic wheel. When the there is a negative pressure peak in the manifold, the next piston TDC will be the compression stroke.

If the MAP sensor fails, the ECU goes into fallback mode, and simply fires the ignition coil at every TDC.





As far as why you are doing this the hard way? I get it. I like to march to my own drum too.

[FredZeppelin]

Excellent, many thanks Beetle.

This engine will go into a bike I'm building from some of the leftovers from Kev Botman's Monzada project.

Cheers.

[beetle]

It would be nice to see the project during the course of the build. I'm quite interested in your progress.

 

[FredZeppelin]

Right now it's part pig's ear, part dog's breakfast, but here is a picture:

[guzzisteve]

I would stick w/carbs.

[beetle]

I would stick w/carbs.

Where's the fun in that?   

[sign216]

My 2cents: I've always enjoyed my MyECU programmable module. 
A terrific piece, but not for the queasy.

[FredZeppelin]

Carbs?

That was Plan A.  I never stick to Plan A.

[guzzisteve]

For Fuel Inj you'll need the sensors installed, or use a later block & cam and possibly heads. Later wiring harness for the MyECU w/works well (mine does). Good Luck on the project.

[lucian]

interesting exhaust set up. Are you staying with that?

[guzzisteve]

What year Nevada engine is in your bike?

[FredZeppelin]

The motor currently in the bike is a V50.  It's a leftover from Steamdriven Kev's Monzada project, as is the Nevada frame. Kev put a Nevada motor in his Monza and I got the surplus bits.

Yes, that's the exhaust I plan to use.  I built the exhaust to fit the Monza motor, so I'll have to build another collector for the new motor since the pipes will be further apart. Once I've finished the collector I'll get the lot ceramic coated to hold the heat in a bit better and fit a heat shield under the tank.  If that's not enough I'll wrap the lot in exhaust wrap and weather the abuse from Kev.

I'm not planning to go to a bigger diameter tubing yet - will get some dyno readings first. 

The muffler is off a Ducati twin, not sure which model. Must be fairly recent because it has a catalytic converter in it.
 
The new motor is a low mileage 2014 V7 which I bought on eBay without any electrical bits.  I have a set of PHF30's but would still have to sort out an ignition, so decided to go for an EFI+CDI kit.