ALFAGTV6.COM

Copied from:
http://www.gotech.co.za/forum/viewtopic.php?t=323

4agedub wrote:Normally the problem comes when the injectors are leaking slightly. When the ignition is turned on, then a spark is generated and it ignites the fuel in the engine.

To overcome this you will need to install a relay onto the coil.

I have this problem - apparently it can cause damage to the starter - bigger concern is kicking the engine back and derailing the timing (?)

Its generally pretty disconcerting.

Anyone else done this mod?

What is a '2a' diode? Radio Shack?

I initially had made a more simple modification - I was only powering the coil packs when the ECU sent a signal to run the fuel pump.
This does not work because the ECU primes the fuel system when you first turn the key and that in turn causes the coil packs to fire before the engine starts spinning...

Maybe 2a means 2A as in 2 Amperes.

When you say kickback, do you really mean something similar to a plenum pop? On this time it's 2X worse as your starter is turning the enigne one way, the engine could turn either way depending on which cylinder goes pop.

Maybe it's time to try the Gotech Pro X or Autronic SM4

What seems to happen is that when the ignition is turned on, the GoTech fires one of its ignition coils - probably just an oversight in the circuit design. This results in 2 spark plugs being fired and if conditions are right in either of those two cylinders, the engine sort of 'kicks' - could be backwards.
The guy reporting it on the Gotech forum stated that this resulted in 2 broken starters. I don't see this as a risk for our engines ... but we all know that Alfa V6 engines must not be rotated backwards for fear of skipping timing.

As for other options ... I still like Megasquirt. The new version is even better and with the MS-Extra-2 code, can read 60-2 and support wasted spark.. I can have this professionally built for ~$600 so its not like I'd have to wield a soldering iron either.
The great thing for MS is the continually evolving tuning tools (love the software!), masses of enthusiastic support, full WideBand 02 support and even self tune. Instead of specifying how much fuel to inject at a given load point, you just specify what the AF ratio should be and let the MS figure it out

I have a feeling both Autronic and the newest GoTech might have both of those options too.

For now, I just want to figure out the riddle of the wiring diagram so I can use the car this summer. Heck, the Alfa convention is in Portland, OR this year and PIR beckons.

Maybe someone with more electrical skills can explain this one to me - I have been studying the Gotech solution for this problem:

I'm having trouble understanding how this will work... from what I can see, the coils will be powered ONLY when the engine is cranking. I don’t see how pin 87 on the right relay will be powered (12v +) when the engine starts and the key is then released.

I am running a Gotech Pro and have experienced the same issue. Before my settings were correct, it was leaving a bunch of unburnt fuel in the chambers. Sometimes as soon as I turned the key to ignition, I got a backfire. I don't see how the schematic above will solve the issue, but hey I'm not a EE. I'll be watching this thread to see what comes of it.

One way around this problem would be to add a small delay for the power to the coil pack. If you had a 2 sec delay after you turn the key to the run position, it would give the starter time to begin rotating the engine before the coils started firing. It's not a perfect solution as you would still have the problem if you were just turning the key to run, but not starting the car within the delay time.

I'm going to keep thinking about a better solution, but that was one thing that came to mind.

I dont have that problem because my coil pack(155) does not have internal ignitors like the vr6 coil pack which is the main problem. It only fires after the engine rotates. Andy if you can find a way to delay it should be perfect. I will ask the chaps from gotech at races this weekend what they do.

I have removed the ignitors that came with the VR6 coil pack, so that isn't what is causing the initial spark. I imagine you can buy a small adjustable delay timer from somewhere like Newark. I'll look around later this week.

Hi - here is an email from Louis Cloete of GoTech - I dont think he will mind me posting this.

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That drawing is precisely what you need to do. You can go to any electronic shop and purchase a 2amp diode.
The diode must allow power to the relay when the starter is engaged, but not back to the soleniod.

How it works? It's actually VERY easy.
When the ignition is turned on the Gotech relay will supply power to pin 30 of the coil relay. But it will not switch on yet. When the starter is engaged the coil relay will switch on ( Pin85 Ign power). Because pin 85 and 87 is joined the relay will stay on. The coil relay will only switch off when the Gotech relay is switched off, then there will be no power on the coil relay.
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I'll try it this weekend.

This did work as Louis described.
I used a 2.5Amp 1000v Recrifying Diode ~ Radio Shack PN 276-1114:
Note that the silver band indicates the direction in which the current will flow, so the lead closest to the band points to the relay.

The coils only start firing when the starter is engaged and I can confirm that the engine keeps running once the key is released.

So why is this not implemented in the original design?

This is great news! I'll give it a try this weekend!

Thanks,

Andy Micheal,

Just curious how you wired up the GoTech MFI Pro. Do you both run VR6 coil packs (Single pack with 4 pin input & 6 plug output)? Did you wire the diode to the ign wire (Black 2.5mm) of the starter motor? The other wire is constant power. I am still trying to figure out the wiring on mine as it has been a while since I did it. Would be great if any of you have some pics on your relay wiring. Thanks

Yes, I am running a Gotech Pro with VR6 coil pack. I added the diode set up to my car just this last weekend and it seems to have solved the problem. Took me a while of studying the schematic, but now it all makes sense. I ran the black 12V signal that goes to the starter solenoid into the diode. (this is probably a 10 ga black wire in the factory harness). From there it goes into pin 85 of the coil pack relay. (this is what closes the relay contacts). Also coming out of the doide is the jumper that goes to the line providing power to the coil pack. this is the wire that goes from pin 87 of the coil relay to the actual coil pack. So follow the schematic and all should be well.

good luck,