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Need Fuel Pump Power-Feed Help Please;

Posted: Fri Apr 01, 2005 2:04 pm
by junglejustice
So, I finally took time out this week to get the GoTech installed...

All's fine and I could actually start it right up with Domingo's pre-loaded 3.0 map...

Problem is that with the AFM disconnected, you don't keep a constant power-feed to the fuel pump... (Alfa has a emergency/security feature that only allows the fuel pump to be powered while you are either cranking the ignition - actuated by cranking the key - after which time the door in the AFM takes over and it's movement actually triggers the "fuel pump feed circuit" within the AFM...)

With the AFM now completely removed, the action of cranking the key actually provides enough fuel to be injected at start-up to run the car for a few seconds, but as soon as you release the key back to the simple "on and running" position, there is no power feed to the fuel pump.

What/where would be the best way/place to jump to the fuel pump from up in the engine bay somewhere - still somewhat actuated and deactivated by the ignition on/off....? (I realize that in the unfortunate event of an accident, the pump would maintain pressure to the system), but for now, that'll have to do....

I still have the stock ECU in there, but it's not hurting anything as it's only function now is to drive the cold-start injector as well as the fuel pump power-on feature at start-up. I wish I knew which of the AFM harness' pins to jump to actuate the fuel pump's "on-running" status, although, I will probably remove all of that crap soon!

Anybody?

Thanks in advance.

Posted: Fri Apr 01, 2005 3:02 pm
by Greg Gordon
The best way is probably at the AFMs wiring harness. I dont know which two wires to bridge together and I am down in Mexico right now so I cant check. If nobody else answers give me a call tomorrow at home and I will check it out.

Posted: Fri Apr 01, 2005 5:26 pm
by Zamani
JJ,

Why don't you just rewire the fuel pump to turn on as soon as the key is in the start position.

Posted: Fri Apr 01, 2005 7:22 pm
by junglejustice
Now that wold be too easy now, would it not Zamani... Thanks for the input - I was trying to find a fast solution as the car needed driving right away...

Where is there power to the pump from the firewall?

Posted: Sat Apr 02, 2005 12:04 am
by Greg Gordon
Bridging the two wires from the AFM would do exactly that. It takes about 5 seconds to install a wire bridge.

Posted: Sat Apr 02, 2005 12:51 am
by Mats
Why not use one of the switched outputs from the gotech, that would also be a safety feature as you could make it turn off the pump if the engine stalls (ie. in a crash)

Posted: Sat Apr 02, 2005 1:03 am
by junglejustice
Well, that's the route I'm going (using one of the GoTech aux outputs...) but at that moment, I was looking for a fast solution so that I could get back to my shop...

I ended up plugging the damn AFM back in, and just prying the flap open with a wrench...! Works!

Now I can take my time with it.

Posted: Sat Apr 02, 2005 1:32 am
by Mats
ah, thought it was more then a "limp-home" thingie.

Posted: Mon Apr 04, 2005 3:14 am
by SamW
JJ, let me know your solution, I had thought about that, but I am still holding off installin GT until I get my Verde finished. Also, does GT need the CSI?

Posted: Mon Apr 04, 2005 8:45 am
by junglejustice
Sam,

The GoTech install went good. What I'll do is start a new tread under that heading so that we can discuss issues and solutions there....

Posted: Mon Apr 04, 2005 2:43 pm
by SamW
Just let me know and I will keep an eye out for it.

Posted: Thu Jul 21, 2005 9:53 am
by 4agedub
You can use the optional output to switch the fuel pump. Just remember that the fuel pump output is negative switching and that a relay should be used. In the software, f5 configuration screen you can set the fuel pump/shift light option to -600 to safely turn the fuel pump on and off.

The fuel pump will then run for a second or two when the ignition is turned on to prime the system and then turn off again till the engine is cranked.

Posted: Thu Jul 21, 2005 10:14 am
by Andrew.b
I "think" JJ and co. are using the basic gotech mfi, and use the blue/white optional output wire, to fire the coil directly.




4agedub wrote:You can use the optional output to switch the fuel pump. Just remember that the fuel pump output is negative switching and that a relay should be used. In the software, f5 configuration screen you can set the fuel pump/shift light option to -600 to safely turn the fuel pump on and off.

The fuel pump will then run for a second or two when the ignition is turned on to prime the system and then turn off again till the engine is cranked.

Posted: Thu Jul 21, 2005 10:33 am
by 4agedub
If youre running with the MFI then you need to go the route as Andrew explained. Remember to move the jumper setting in the ecu to the correct position when using the optional output. (Blue/white)

Posted: Fri Jul 22, 2005 3:00 am
by SamW
I think I need to do this, I loaded Jes's map last night, it runs better, but still runs out of steam at about 2k rpm, so I think it is starved for fuel, DaveH said the same thing about the relay and negative switch, I will be doing this this weekend...