Flybackless box converted?

[SamE30]

Hey Guys,

I have a early 3.3 box with no flyback installed in it (I wasn't aware as I bought it like this). I recently switched harnesses to a V3 twinsheild to clean it up.  Once I switched harnesess the car ran terrible, misfiring, won't idle. Check all the wires 10 times over and still couldn't figure it out. Turns out on the old custom harness, there was a flyback diode installed in the injector power line externally but the other end was broken off, so I had no way to know where it went.

Also my box has no flyback installed, but the twin harness has it pinned for it. I would like to get flyback installed and figure out what damage it did to the VEMS and have it checked over.

The car is a E30 M20 2.8 stroker, running Seimens DEKA 630's (I'm switching to EV14's) High-Z. GM coils running wasted spark and the factory BMW VR crank sensor and running the 3-wire idle air motor.

I know there is a place in the US that does it, but I can't seem to find the contact info on the site and I need it ASAP. I would like to send it there as I'm in Canada, and it's closer than EU. Or would it be better to get a new VEMS?

Thanks,

Sam

[VEMS]

Hello Sam,

Please contact Jason (vems.com in the US) i am sure he will be able to redirect you to the nearest dealer who can help you out.

If the ecu was used with external transient suppression diode flyback before and you can still read the part number on the diode (most likely 1.5KE18 or 1.5KE30) you can replace it and connect the new diode (of same type) in the wire going to ec36-pin#23 before the econoseal connector (assuming the ecu is not damaged). If the car still idles now, there is a good chance the ecu is still okay.

Best regards, Dave

[SamE30]

Amazing! It all makes sense now. I connected the diode to the flyback pin and it started right up and idled perfect.

One more quick question. I don't have 5v pull ups for launch control, map switching and no lift shift. I can take a 5v with a 4.7k resistor to the analog inputs and then pull them to ground right? My ecu currently doesn't have inputs. And I can wire them to the EC-18 2,3 and 6?

Don't mind my garbage drawing but like this?

[jrussell]

That would not work with one pull-up resistor. You need the resistor between the ECU inputs too, so 3 resistors is the proper way. There's some more detailed discussion over in this thread if you want more: http://www.vemssupport.com/forum/index.php/topic,2402.msg23235.html

This is how you connect it with external pull-up. Just do this 3 times for your scenario.

[SamE30]

I will try that today.

Thanks,

Sam