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Injector wiring query
stuart_g - 26/7/18 at 05:34 PM

I am helping a mate with a Ford Anglia build which has a 2.0l silvertop Zetec in it running Jenvey throttle bodies.
The ECU he has is a M-tech V4 which is essentially Megasquirt 2 Extra version 3.4.2

We have got the car running but sometimes it diesn't run that well. We are also struggling to find a company actually willing to set it up on a rolling road. We have been thinking it may be time to get either an Emerald or an Omex.

I have been looking at the wiring diagrams of the Emerald and Omex and have noticed a difference in the injector wiring compared to the wiring diagram we used.

The difference is that on the M-tech diagram injectors 1&3 and 2&4 are paralleled where as on the Emerald and Omex injectors 1&4 and 2&3 are paralleled. Does any one know why this is?

Here is the diagram we used to wire the car.



Here are the settings from the ECU.



Any help would be great.

Thanks in advance..


[Edited on 26/7/18 by stuart_g]

[Edited on 26/7/18 by stuart_g]


luke2152 - 26/7/18 at 09:21 PM

It might make a difference to smooth idling. Some engines may prefer one way or the other due to firing order. But it wont make any real difference after all carbs are not timed at all and they do just fine. Injection timing just isn't that important.


SPYDER - 26/7/18 at 10:26 PM

The diagram shows a wasted spark type setup using only a crank sensor. The ECU has no idea which individual cylinder is on which stroke. It only knows which pair are "up" and which pair are "down". The logical pairing would be the Emerald way.
As already stated, however, with your setup it won't matter much.
4 squirts alternating can yield consistent results on a wasted spark setup. You need to keep an eye on idle pulse width though.
The VE Analyze Live feature on Tunerstudio can get your VE table tuned to a large extent.

The drawing shows the O2 sensor wired directly to the ECU. Is this for a narrowband type?


britishtrident - 26/7/18 at 10:27 PM

It is bank firing of companion cylinders, on a straight 4 cylinder engine cylinder 1 is always paired with 4, and cylinder 2 is paired with 3.


stuart_g - 27/7/18 at 09:55 AM

quote:
Originally posted by SPYDER
The diagram shows a wasted spark type setup using only a crank sensor. The ECU has no idea which individual cylinder is on which stroke. It only knows which pair are "up" and which pair are "down". The logical pairing would be the Emerald way.
As already stated, however, with your setup it won't matter much.
4 squirts alternating can yield consistent results on a wasted spark setup. You need to keep an eye on idle pulse width though.
The VE Analyze Live feature on Tunerstudio can get your VE table tuned to a large extent.

The drawing shows the O2 sensor wired directly to the ECU. Is this for a narrowband type?



We aren't using a O2 sensor.

It just seemed strange that the injectors aren't paired the same as the coil is. The way the injectors are wired is one cylinder up and one cylinder down.

Would it be better to rewire the more traditional way and would I need to make changes to the settings in the ECU?


stuart_g - 27/7/18 at 09:57 AM

quote:
Originally posted by britishtrident
It is bank firing of companion cylinders, on a straight 4 cylinder engine cylinder 1 is always paired with 4, and cylinder 2 is paired with 3.


This is what I thought, that is why I thought it was strange not to be wired that way.

Not sure wether it would make any difference to the running of the car if they were wired 1&4, 2&3?


SPYDER - 27/7/18 at 10:52 AM

Just change the wiring. Or swap plugs. Where did you get your VE and Ignition tables from, and for that matter, the rest of your settings?
I would advise the fitting of a wideband sensor. You could then use VEAL on Tunerstudio to improve your VE table.
I'm not surprised that the MTech drawing is erroneous. They don't exactly have a stellar reputation.


stuart_g - 27/7/18 at 11:19 AM

VE and ignition tables are default.
The other settings were put in by myself from the Mtech instruction/setup manual.
The ECU was on an earlier version of firmware (2.0) which was simpler layed out. I have upgraded and imported settings from a backup.

If I change the wiring would I then have to change the sequetial injection settings to semi sequential?

I could do with a VE and ignition table from an ECU already setup for 2.0 Zetec??

Can't use live tuning as unregistered version of Tuner Studio.

[Edited on 27/7/18 by stuart_g]


SPYDER - 27/7/18 at 11:20 AM

You won't need to change any settings. Can't you just swap the plugs?
Why is it set on SEQUENTIAL SIAMESE?

[Edited on 27/7/18 by SPYDER]


stuart_g - 27/7/18 at 11:41 AM

Ahh yeah I see what you mean. Can just swap injector plugs either 1 and 2 or 3 and 4 to achieve the correct wiring. will do that.

Not sure why iut is set as sequential siamese, it was set as that after restoring backup. Shouldn't that be set to semi sequential?

Think a wideband sensor would be a good idea and have boss in exhaust. What one do I need 2 wire, 3 wire etc or is a wideband a standard?


SPYDER - 27/7/18 at 11:57 AM

It should probably be on UNTIMED INJECTION. SAVE the setup before making ANY alterations.
I use and recommend the 14POINT7 Spartan wideband. Usually available from ExtraEFI.


stuart_g - 27/7/18 at 01:25 PM

I've swapped injector plugs 3 and 4 over. Engine still runs but not very smooth. Haven't altered any settings in ECU yet though.

Would VE and ignition tables from a running car help do you think?


SPYDER - 28/7/18 at 03:09 PM

Tables from a Jenvey equipped setup might help. Might not. No harm in trying anything but without an oxygen sensor you are effectively blind. I would normally suggest going on the MS forums but your MTech ECU will simply raise their hackles.


40inches - 28/7/18 at 04:51 PM

You could have it set up on a rolling road for about £150-200. A wideband set up will cost about £130-150 anyway.