DET3 FI on MX5 NA

[BGTMIDGET7476]

Good Morning Forum Folk.

I have been put onto there since purchasing my DET3 for an engine conversion I have completed.
Background is always a key in these things so here is what I am running.


What you have there is a 1.8 MX5 lump shoved into a 1974 MGB GT, the install was completed before summer and I'd been rolling around on standard MX power which in an MGB GT isn't too bad.
As with anything like this I soon got bored and wanted a challenge, so as the MX lump lends itself to a little boost I designed mounts and installed the C-Class Supercharger you see there.


A friend suggested the Piggyback FI mode DET3 above Powercards and rightly so, it's an amazing bit of kit.


Anyway on to the question at hand:
I found this wiring diagram on a site for the MX5 (as there is not one from ECUMaster yet), but I am wondering 2 things and would like to know if someone could tell me.

Port 18 Power out, seems to suggest it goes to the live for the injectors. Is this correct? it also points to a component N.75, I am guessing it's a resistor of some sort but looking at other installs I cannot see anything similar.
Also I purchased DET3 with the inbuilt MAP sensor so I presume the Map Switch PinOut can be left alone?

Many thanks for you input in advance.
Nathan

[ktsirigotakis]

Hi my friend I like your project sounds very interesting!!!!


N75 is the boost controller!!!! vag cars call it N75! in your case you don't need it better for me is to use power 1 & 2 to control your injectors

now the built in map you can use it to throw to the garbage the MAF that you have there and use map.

at that diagram that you have at pin 2 they put the wide band out put to have reading inside the program.

you can read the manuals of det3 and read here at the forum how you like to wire the det3. det3 is an Peggy back ecu that you can wire it in different ways depend on your needs!!!!!

[BGTMIDGET7476]

Hi

Many thanks for your input.
I have been using a standalone LC2 but in that case I may as well connect it up to the DET3.

That makes sense on the boost controller, never thought of that .
Oddly enough I was about to mention the injectors, putting all 4 on that one bank seemed a little excessive and I didn't want it to overload the out etc. I currently have them ready to connect so I'll spread them across the outputs.

Thanks again.

Hi my friend I like your project sounds very interesting!!!!


N75 is the boost controller!!!! vag cars call it N75! in your case you don't need it better for me is to use power 1 & 2 to control your injectors

now the built in map you can use it to throw to the garbage the MAF that you have there and use map.

at that diagram that you have at pin 2 they put the wide band out put to have reading inside the program.

you can read the manuals of det3 and read here at the forum how you like to wire the det3. det3 is an Peggy back ecu that you can wire it in different ways depend on your needs!!!!!

[ktsirigotakis]

connect the lc2 because it takes measurements and you can see it on your fuel table the a/f ratio makes your life very easy to tune it!!!!

tip.

if you delete the maf take measurements as n/a

[BGTMIDGET7476]

connect the lc2 because it takes measurements and you can see it on your fuel table the a/f ratio makes your life very easy to tune it!!!!

tip.

if you delete the maf take measurements as n/a

Thanks for the advice, over this Christmas break I have now managed to get it running, well at least ticking over.
However I have noticed to get a stable tickover the VE table settings need to be into the 110 mark, is this correct?
I have set all the sensors as required, but getting a nice 14.7:1 and stable at tickover does require quite high levels.

I have done a small road tune and this also seems to require high levels in the VE table, generally up to the 150 mark, my concern is the 3D table seems to be totally red and not progressive like some examples I have seen.

Any advice on this would be great, I can provide a screen shot of the tables and logs.

[Jadzwin]

Did you enter correct injector size ?
What is your divider ?
What is your fueling strategy (speed density or alphaN) ?
What is your injectors battery calibration constant

[BGTMIDGET7476]

Did you enter correct injector size ?
What is your divider ?
What is your fueling strategy (speed density or alphaN) ?
What is your injectors battery calibration constant

Hi
Thanks for the response.

Injector opening time is 1.000ms
Injector size is 254cc
Speed Density as I was lead to believe this would be better for the "Charged" install.
Battery Voltage Correction 0.100

I have it set to Bank Fire and I believe the Divider is 2.

Many thanks.

[Jadzwin]

Looks correct. You can just lower your inectors size to lover VE table values.
And please check if your number of cylinders is correct.

[BGTMIDGET7476]

Looks correct. You can just lower your inectors size to lover VE table values.
And please check if your number of cylinders is correct.

Thanks for the info.
I ended up flashing the DET3 to standard then flashing back to Fuel Implant and adding the same settings seemed to keep the numbers low.
Managed to have it working and boosting for all of a day before the engine ate something or threw a Rod, so at the moment it's game over. I have a new engine on order but I need to see what caused this failure first.

Cheers.