MX5 Link Inj 5,6,7,8 pins

[Monsterbishi]

Good evening all,

Am contemplating doing something daft with my MX5 which has a Plugin G4+ which will involve eight fuel injectors (Can you guess?), are the pins for the Aux Injectors mapped onto the factory MX5 pins at all?

Also, does anyone have a startup map for a TFI Ignition Ford 302w V8?

[Simon]

On the plugin Inj drives 7 and 8 are only low power so would not be suitable for injection control without additional hardware.

You would be better to pair injectors and run group fire on the existing 4 drives.

[Monsterbishi]

Group firing it is then :-)

So for the pairings, would I follow the spark order?, ie:

Inj1 1,3

Inj2 7,2

Inj3 6,5

Inj4 4,8

 

[Simon]

8 Cylinder, firing order 1 8 4 3 6 5 7 2.   Pairs as per OEM Toyota 1UZFE wiring.

·	Injector drive 1 is wired to injectors for cylinders 1 and 7.

·	Injector drive 2 is wired to injectors for cylinders 2 and 8.

·	Injector drive 3 is wired to injectors for cylinders 3 and 5.

·	Injector drive 4 is wired to injectors for cylinders 4 and 6.

[Monsterbishi]

Cheers for that, I've plumbed the eight injectors to run off the four drives and am building up a basemap to get the thing started but I have a question -

Given that it's TFI so only have a single trigger, As far as the Injection Mode goes am I right in thinking that I should set the Injection Mode to Multi Point Group and the Injection rate to 1/2 cycle so that the first two drives pulse on the first 360 degrees and the second two pulse on the next rotation?

 

[Adamw]

The TFI system has one narrow tooth that comes around every 720 crank degrees so that is all you need for sequential but whether semi-seq is a better option or not will depend on how the injectors were paired.  How did you end up pairing them?

[Monsterbishi]

I currently have them paired with the banks of the 302w:

Firing Order: 13726548

Bank1 - 1,7,6,4

Bank2 - 3,2,5,8

Inj1 - 1,7

Inj2 - 6,4

Inj3 - 3,2

Inj4 - 5,8

I haven't wrapped the harness yet so it's not a big deal changing things around.

[Adamw]

I would use multi-group mode in this case and set injection rate to 1/2 engine cycle.  It will fire injector drives 1&3 together, then 2&4 together 360deg later.  You will only have two injectors in each rail firing at the same so pulsation will be acceptable.  I dont think there is any merit in changing wiring for semi-seq in this case as the firing order does not lend itself well to the semi-sequential strategy.   

[Monsterbishi]

Cool, that ticks another box then - thanks for taking the time to reply 

[Monsterbishi]

We're up and running now, I have a couple of small questions if you don't mind?

The first is about the ignition table - is the timing table total advance including base timing or is it on top of the base timing?

The second is regarding the Master Fuel setting - am I right in thinking that it's best to keep this number as low as possible whilst maintaining safe air/fuel ratio's so that there is maximum flexibility in the fuel table?

[Adamw]

1 hour ago, Monsterbishi said:

The first is about the ignition table - is the timing table total advance including base timing or is it on top of the base timing?

Total including base timing.  

 

1 hour ago, Monsterbishi said:

The second is regarding the Master Fuel setting - am I right in thinking that it's best to keep this number as low as possible whilst maintaining safe air/fuel ratio's so that there is maximum flexibility in the fuel table?

Correct, although it is not usually all that critical.  If you used a Master fuel that was way too big you would end up with very small numbers in the fuel table so you get less adjustment resolution.  If you have numbers around 50% in the middle of your fuel table or around 30% at idle it is in the right ball park.