my AEM Infinity conversion 3.0

[mikedsilva]

Here is a pic of the current install And below it is the lead up to it...






The car I am converting, started life as a 3.0 carrera but had been fitted with a 3.2 Carrera motor and stock motronic ecu.
I've rebuilt a 3.0 C motor, but the CIS was questionable so I took the opportunity to convert to EFI, and the Rasant kit is what I chose.

I'm at the stage of planning wiring; I really don't understand most of it and the fact my car has been modified to fit the 3.2, adds an element of uncertainty (for me).

The 3.2 ecu is mounted behind the left seat.. and there is a taped loom of 4 wires from the front of the car, which is spliced to the ecu now. They are yellow, black, purple, and red. Any ideas what they are?



The Rasant instructions say to tap into the tacho and the ignition-on at the rear fuse panel in the engine bay. But I am that poor with electrical tasks, that I really don't know where to do it, especially since this car has been modified already with the 3.2 conversion...



Also, the Rasant kit comes with a long red wire, marked for fuel pump; I take it this is to be run right to the front of the car and directly connected to the pump. Currently, my cars fuel pump runs as soon as the key is turned to ignition-on... which I understand is not how it is meant to be.. (they are supposed to only pump when the starter begins cranking the engine); I assume this means that the AEM ecu will now be controlling the pump and bypassing whatever my car was doing before.

Any tips or hints will be muchly appreciated.
Mike

[mikedsilva]

sorry, i dont know why those photos are that large.. I used imgur to link them..

[stevesc_us]

Why don't you try calling Andrew at Rasant.

Porsche 911 Engine Management EFI Kit- 2.7/3.0/3.2L With ITB's - Rasant Products

[mikedsilva]

Andrew has been assisting, however because my car is a bit of a "bitsa" it doesn't lend itself to off-the-shelf diagnosing..

I have since discovered that the wiring from my carrera ecu, runs to the front compartment fuse panel.
The 2 black wires from the ecu, and both joined, and turn into RED wires that mount to the bottom of the fuse panel. I'm guessing they are grounds.
The red wire is a feed direct to the battery with a fuse in-line. Surprised my car isn't draining if the ecu is always connected?
The purple wire heads up to the tachometer area.
The yellow wire from the ecu, also goes to a spot on the bottom of the fuse panel in the front compartment. I thought the yellow might have been switched power or starter? but even when disconnected from the front fuse panel, the car still starts and runs perfectly. So, I don't know what this yellow wire is for.

Either way, looks like they will all be disconnected. The Rasant wiring has a wire for the tach, a wire to go direct to the pump, and it also needs switched power; so that is my next job to find switched power at the rear fuse panel. It has been mucked around with, so I am not entirely sure what is still connected; when you see blue bullet connectors, you know that isn't factory!

This is the fuse panel.


This is the yellow wire that feeds to the 3.2 ecu.


These are the 2 red wires, that are joined to the 2 black wires that ground the ecu.


Here you can see the 2 red wires joining to the black.


This is the solid red wire that goes to the battery. It is not switched.


Overview


Here you can see that 2 wires from the ecu are both joined and connected to the ground.

[mikedsilva]

I think I figured it out.. I'm gonna get rid of it all. I found what I believe to be switched power at the rear fuse panel.

[Tippy]

The stock Carrera 3.2 cars have a large DB55 pin connector going into the DME. Somewhere in there, is an 8 gauge wire that feeds all the power. I cut that wire there at the DB55 connector and pulled power from there for my MegaSquirt fuse/power block.

On to the tacho:

I don’t remember the pinout, but there’s a pin on these cars stock to goes to the tacho. I simply ran my ECU tacho out to that pin with a spade connector to trigger the tacho. Works fine.

Being your car is an SC, I’m not sure how they triggered the tacho from the DME DB55 connector?

Hope this helps.

[Elombard]

The wiring diagrams for the SC and carrera are both available on line and you can figure out the function of the wires there.

I am like you, all of that is going away, so I am not sure it really matters. The fuel pump is easy to figure out. You should be all set.

Finally, I would say that if you are super intimidated by wiring a stand alone fuel injection swap might be better to leave with a knowledgeable shop.

It looks like you are on the right track so maybe you are better than you think :-)

[FstTarga]

I wired my own ms3pro setup into my car using some rasant stuff along the way. I’d never really done any wiring before and my car ran (rebuilding the engine so I don’t blow it up) so you should be good. Just keep using your volt/ multi meter, don’t guess, and take your time and it’ll reward you with a reliable set up.

Also if you are using the rasant crank pulley and trigger make sure it’s got a 60-2 tooth wheel and not a 62-2, Andrew got a bad batch a few months ago that had 2 extra teeth, he made it right for me so just make sure that you won’t be held up by that. Other than that little issue the rasant products have been top notch that I’ve used

[mikedsilva]

Originally Posted by FstTarga

I wired my own ms3pro setup into my car using some rasant stuff along the way. I’d never really done any wiring before and my car ran (rebuilding the engine so I don’t blow it up) so you should be good. Just keep using your volt/ multi meter, don’t guess, and take your time and it’ll reward you with a reliable set up.

Also if you are using the rasant crank pulley and trigger make sure it’s got a 60-2 tooth wheel and not a 62-2, Andrew got a bad batch a few months ago that had 2 extra teeth, he made it right for me so just make sure that you won’t be held up by that. Other than that little issue the rasant products have been top notch that I’ve used

HI, thanks for chiming in. On the note of the crank trigger, yes, I am using it. Andrew sent me a new wheel but I thought the old one had 60 and the new one had 58?
What would have happened if I had run the old one?

[mikedsilva]

Originally Posted by Tippy

The stock Carrera 3.2 cars have a large DB55 pin connector going into the DME. Somewhere in there, is an 8 gauge wire that feeds all the power. I cut that wire there at the DB55 connector and pulled power from there for my MegaSquirt fuse/power block.

On to the tacho:

I don’t remember the pinout, but there’s a pin on these cars stock to goes to the tacho. I simply ran my ECU tacho out to that pin with a spade connector to trigger the tacho. Works fine.

Being your car is an SC, I’m not sure how they triggered the tacho from the DME DB55 connector?

Hope this helps.

yes it does help.
I think I have found the wire that goes to the tacho so I will simply connect my Rasant harness to that wire.

My other issue now, is that the Rasant harness is designed to mount the TPS sensor on the right cylinder bank (4,5,6). I didn't realise that TPS sensors only rotate 90 degrees, and the one I bought worked better on the left side of the engine, but this puts a strain on the wiring. So I need to find a 6 inch TPS extension cable, or mount the TPS on the right. But if I mount it on the right, then the harness is "smooshed" against the engine shroud as the harness exits down. Also, the voltage end points for the TPS will be 'reversed'.. does the AEM ecu care whether the higher voltage signal is the idle setting?

Or is there a TPS that I can mount on the right bank, that has the wire harness exit sideways?

[mikedsilva]

Originally Posted by Elombard

It looks like you are on the right track so maybe you are better than you think :-)

maybe.. fingers crossed!

[mikedsilva]

TPS has been taken care of.. bought some connectors to make an extension.

Now, for the fuel pump, the Rasant kit has a power wire to activate the pump and we are supposed to disconnect the existing positive cable from the pump, and then connect the new one to it. It's a little difficult to access on my car... but I traced the power wire for the pump which runs directly to the bottom of fuse 1 - "fuel pump". So my thought was remove the fuse and then connect the Rasant power feed for the pump, directly to the lower tab on the fuse panel, which will then run direct to the pump. Should work fine? Or is there anything fundamentally wrong doing that?

['76 911S 3.0]

Rasant power distribution panel should have a relay and fuse for the fuel pump, hooking it up the way you described should work perfectly fine.

If you are using 96.3 firmware on the Infinity, it does not care if the voltage goes low to high or vice versa. If you are picky and find that voltage with the throttle closed is close to 4.5v, you can swap the +5v and sensor ground wires on the connector to invert the voltage.

[mikedsilva]

Originally Posted by '76 911S 3.0

Rasant power distribution panel should have a relay and fuse for the fuel pump, hooking it up the way you described should work perfectly fine.

If you are using 96.3 firmware on the Infinity, it does not care if the voltage goes low to high or vice versa. If you are picky and find that voltage with the throttle closed is close to 4.5v, you can swap the +5v and sensor ground wires on the connector to invert the voltage.

Thanks for replying.
I don't know what firmware I have but I'm ok with the extension. Just waiting on some hoses and connectors so I can do fuel lines (my kit didn't have an 8mm barb connector for the return line) and then whack it all back in..

['76 911S 3.0]

When you register the ECU on aeminfinity.com, just make sure to download v96.3 universal

[mikedsilva]

https://www.youtube.com/watch?v=hZGwNegWOfI&t=

[mikedsilva]

Short story, with help from Mr Kosmal, I got it running. I'm just using the tune that came supplied from Rasant. I did experience the run-on condition that some others have experienced.. where you turn the key off but the engine keeps running. With Al's patience and help, he described how to fit a diode between the blue wire and the Generator bulb on the dash display.. now there is no "backfeed" current to the ecu and it shuts down when the key is turned.

One other thing I have noticed, is that my pump runs for 4 or 5 seconds after the key is turned off.. Not sure if this is a setting somewhere in the tables?

[kuehl]

Originally Posted by mikedsilva

fit a diode between the blue wire and the Generator bulb on the dash display.. now there is no "backfeed" current to the ecu and it shuts down when the key is turned.

Yup, i had to do that.

Originally Posted by mikedsilva

One other thing I have noticed, is that my pump runs for 4 or 5 seconds after the key is turned off.. Not sure if this is a setting somewhere in the tables?

,

I have same issue, interested in reading your solution.
I recall a setting for priming (seconds) when key is turned on.
Pondering if I have a wiring issue (feedback to ECU or relay).

[mikedsilva]

yeah, this one is confusing me a little.. How did you wire your pump to the ecu? The advice to me when installing was to unbolt the old positive signal wire from the pump and tape it up.. then run an extension from the pump signal wire on the ecu direct to the pump and let the ecu run everything.

Well, I didn't quite do that.. Because of the location of my pump and how difficult it was to get a spanner on the terminal nut, I traced the positive wire for the pump back through the car, and I believe it runs to the bottom of fuse 1... so what I did was to remove the fuse completely, and then run the ecu pump signal wire, to the bottom terminal of the fuse block so it in effect, connects directly to the pump.

I suspect that my methodology is not correct.. because when I removed the fuel pump relay, the pump would not run at all.... If the ecu is supposed to be controlling the pump 100% then I don't think it would know if the relay was installed or not.
When I get some time, I will need to get back under the car, and disconnect that terminal and run the ecu pump wire directly to the pump itself.

How did you connect yours?

[kuehl]

My model is a 87 911, modified 3.2 block .

I'm using a higher output Bosch pump.

I believe I took a short cut and spliced into the original motronic harness.

I'll take a look at it and get back to you.