Questions about injector setup for a standalone

[astondg]

I have a 2.3L M20 with a standalone ems that has 4 injector drivers. The guy that installed it has connected all the injectors to one driver so they all fire together and in the ECU setup "Multipoint 1" is selected as the injection arrangement (definitions at bottom). My questions are:

1) How are the injectors fired on the standard M20? The same as mine, in smaller batches (if so how many at once)?
2) What benefit (I'm thinking fuel economy) would I get from a different arrangement to what I have now? Or how much is what I have effecting my fuel economy now?
3) What would be the best alternative, 2 lots of 3, 3 lots of 2? And if I group them which do I group (1,3,5 & 2,4,6 ? what about 3 lots of 2?).
4) How do I go about this? Can I just connect the wires to the injectors and the correct pins on the ECU? How do I tell the ECU when to fire what? Is that the injection arrangement? Do I change it to "Multipoint 2" in the ECU setup? Is it more complicated than that? Will the map need to be changed?

Multipoint 1 : Regardless of the number of cylinders the injectors will be fired twice every cycle (two complete engine revolutions).

Multipoint 2 : Regardless of the number of cylinders the injectors will be fired once every cycle (two complete engine revolutions).

I don't know much about this, as I am sure you can tell, but firing all the injectors all the time seems very inefficient to me and the fuel consumption isn't great so if it can be improved I'd like to do something to fix it without paying someone else. Even if you can point me to some information about this it would be helpful.

Thanks,
Aston

[Demlotcrew]

I have no idea, but i would say that three banks of two will give you most flexability, also the M20 doesnt really have a cam position sensor as such maybe thats why he put them all on one driver?

Andrew

[Andy335Touring]

On the M30 (and pressumably(sp?) the M20) they are fired in threes if i remember correctly ?

My Emerald is wired to fire them in pairs. If you wanted to wire yours like mine heres how it is on mine.

I think the firing order is the same on the M20 as it is on my M30 ?

Firing order is 1-5-3-6-2-4

Injector driver one is wired to cylinders 1 + 6
ID two 2 + 5
ID three 3 + 4

I'm not sure how it will affect your fuel consumption firing in either threes or twos ? I was told fully sequential firing helps fuel economy slightly but does nothing to improve the power and it's supposed to cost you extra labour on the rollers in set up time to time the injectors so they fire as the inlet valve is starting to open.

I think it's Multipoint 2 you want according to this quote ? I think it would be best if you contact the ECU maker to see whats best.

" The injectors themselves are connected to the fuel rail via a clip and Ԛâ€ËaOÔš' ring which has to contain the high pressure within the fuel system. An injector is simply an electric valve or solenoid. Fuel is supplied to the injector at a known and regulated pressure, and the valve or solenoid is normally closed. Fuel is introduced or injected to the engine by firing (opening) the injector for a predetermined period of time once per engine revolution or per engine cycle. The longer the injector is held open the more fuel is introduced. This injector time is known as the Ԛâ€Ëapulse widthÔš' and the technique of varying fuel in this manner is known as Ԛâ€Ëapulse width modulationÔš' as it is the pulse width that is varied according to requirements. Since the fuel injected is per revolution or cycle, as engine RPM is increased, so is the number of times the injectors are fired. This has the effect of meeting the engine's requirements for fuel regardless of rpm. "

Some very good info on fuel injection on the site where i took the quote.

http://emeraldm3d.com/ems.htm

I can't remember the out come of your last thread about fuel cut out on a closed throttle but did you change the settings so it cuts the fuel with a closed throttle ?

HTH

Andy

[astondg]

So the people with the Mega-Squirts and stuff that have the injectors in 2 or more groups have a cam position sensor too?

What does the standard M20 do? Are all the injectors fired at once?

Thanks,
Aston

[Andy335Touring]

Ant is your man for MS stuff.

How the M20 fires its injectors might depend on which ECU set up it has ?

My M30 from an E34 was fired in threes i think and i should imagine the face lift E30 320/5 would be fired the same way as the ECU's are the same its just the chip with differant maps on thats changed from model to model like say an E30 320/5 or an E34 530/5 ?

Does your 323 have a traditional dizzy i.e. Vacum and/or bob weights to varey(sp?) the timing ?

[Andy335Touring]

Sorry, i miss read your post, i don't use a cam phase sensor, i think you need one to run fully sequential injection to tell the ECU where in the conbustion cycle the engine is.

[astondg]

Sorry, my second post was being written while you were posting your first. I went away from my computer to answer the phone and got sidetracked and then came back and clicked submit but you had already posted and I didn't know.

Ok, thanks for that. Firing order is the same as my M20 so I guess the injectors could be grouped like that. I have just had it retuned by someone else and he mentioned that he normally groups them but didn't go into any more detail and I forgot to ask. I will talk to him again and see what he says, I would like to do the work myself though if it isn't too difficult.

I'm not worried about fully sequential because I read something similar to want you said, but this one batch fire thing seems to be the other extreme. I want something in between I think that might give a little better petrol consumption.

Thanks for that link, very good info like you said.

I have had it retuned and I asked the guy about the fuel cut but he said he wouldn't turn it on either because I am racing it. He said that if the injectors cut out when you back off, when you try to get on the power again there is a flat spot that is hard or sometimes impossible to get rid of. Not something I want on the track, shouldn't be a problem on the road though.

He also found out that the base timing was out 10 degrees I think so he fixed that and retuned it. That should help the fuel consumption but, although I haven't been able to check it since I got it back, I think it is still a bit high. 10L didn't last long and I can see the gauge drop in a 20km trip.

You have given me some stuff to think about, thanks. Any other comments welcome though. Maybe Ant if he has the time?

Thanks,
Aston

[Turbo-Brown]

Overrun fuel cutoff it such a pain in the arse!

Perhaps the system that brings the fuel back in has improved since the 80s, but my 205 GTi had an overrun cutoff and it made the car a nightmare to drive.

You'd get up to speed, 30mph being a favorite, then try to maintain that speed.

You peek at the speedo and realise you're doing 32 so you back of the throttle which should gently bring the speed down. However, it cuts the fuel dead which makes it feel like you've slammed the brakes on. The speed drops to say 25 with the hapless driver trying to gently ease the gas back in. The ECU finally gets the idea and bangs the fuel on again.

The net effect is that you kangaroo down the road. It's also a big problem in corners where the cutoff which leads to sudden engine braking can cause lift off oversteer

Anyway, back to the injector firing thing: Doesn't seem to matter when the fuel goes in. The M20 had 1-2-3 and 4-5-6 linked to fire at the same time as said so only one injector per batch can be syncronised with the cylinder it's feeding.

My old Volvo 260 had that old Bosch mechanical injection which sprayed into the engine all the time without pause too

[astondg]

That 205 GTi sounds like it was a bit annoying and dangerous too . I think they are supposed to be a fun car though . I've never been in one.

So I could go with either the 2 lots of 3 injectors in that ^ configuration or 3 lots of 2 injectors like Andy335Touring said. If I did 2 lots than I should be getting the same economy as a standard M20 as far as that part is concerned, I imagine the 3 lots would be marginally (maybe negligably?) better.

Could there be any difficulties in doing this or is it mostly just a matter of wiring up the injectors to the pins on the ECU and letting it sort most stuff out?

Thanks,
Aston

[Turbo-Brown]

Mine was funny, when the interior of the car warmed up (and presumably the ECU too) the problem went away, so it was great in summer cos it was always warm! Apparently it's just a case of changing a resistor in the ECU to cure the problem permanently

[Andy335Touring]

I'd try phoning up the ECU makers to see how you should swap the wiring over as last thing you want to do is to short out some thing in your ECU !

Have you not got a manual for it ?

[Chaos]

205 gti jerkiness in traffic is a well known problem.
amazingly the best fix me and a few others found was to use a superchip (normally summit id avoid like the plague)

[Chaos]

On the M30 (and pressumably(sp?) the M20) they are fired in threes if i remember correctly ?

My Emerald is wired to fire them in pairs. If you wanted to wire yours like mine heres how it is on mine.

I think the firing order is the same on the M20 as it is on my M30 ?

Firing order is 1-5-3-6-2-4

Injector driver one is wired to cylinders 1 + 6
ID two 2 + 5
ID three 3 + 4

why have u set them up like that?
as opposed to say
ID1 - 1 and 5
ID2 - 3 and 6
ID3 - 2 and 4

not an area ive much experience in andy, so if my question is a bit stupid then i apologise.

[e30_Turbo]

My ms uses batch firing on 2 sets of 3 injectors, thats were my know how stops, but I have a laptop on route to me so will be able to learn/play a bit more.

All this tech talk makes me realisehow much more I need to know.

(p.s. I only know this much because I watched Ant indentify and cut the wires to the injectors when we installed MS.)

[Andy335Touring]

I must admit i don't know all the ins and outs of it, when i was wiring it up i phoned them up to see how it was supposed to be and thats what they instructed me to do.

[Turbo-Brown]

why have u set them up like that?
as opposed to say
ID1 - 1 and 5
ID2 - 3 and 6
ID3 - 2 and 4

not an area ive much experience in andy, so if my question is a bit stupid then i apologise.

You have 1 and 6, 2 and 5, 3 and 4 because these cylinders do the opposite thing to each other.

1 is inducting whilst 6 has just had it's power stroke and so forth and so on.

Don't think it makes much difference in the end though, hence 1-2-3 and 4-5-6 being linked from the factory.

Apparently fully sequential can give tiny gains in the midrange (no idea why) but ultimate power doesn't change compared to batch.

[calder]

there are a couple of good books available from Amazon.(pick your own country), especially one by dave walker. It explains quite a lot about injector sequencing. iirc sequencing wasn't too critical, but timing and mapping is important as you would expect.

[Andy335Touring]

I keep meaning to get Daves book, may be i'll pick one up when i take mine for remapping if he has them there.

[calder]

it's good bedtime reading seriously, it is well written
I've got Haynes Engine Management by Dave Walker