Need help with factory FI, 77 Bug motor

[Stray Catalyst]

I swapped a bug for a baja and a pile of parts.



Unfortunately, it came to me in pieces, and while I'm familiar enough with carburetion, FI is a new world to me. The PO assured me that it had been running (but of course, he was trying to sell it to me...) before they pulled the engine. I put the engine back in, but now I'm faced with a variety of all-white wires to color code.

I've tried reading the wiring diagrams but haven't gotten anywhere. Can I get some advice on how to correctly wire factory fuel injection on a 77 bug motor?

[Jadewombat]

It's pretty easy. There's only one sensor on the engine for the fuel injection system. It sits in the passenger side cylinder head and is called a temp II sensor. The rest is just hooking up manifolds, a resistor pack the injectors comes with mounts up on the firewall, and mount the ECU. The power for the ECU goes to the negative side (-) of the ignition coil. You'll also need to put a "T" fitting in the fuel line near the transaxle and mount the electric fuel pump in the rear of the car (on the underside of the parcel tray) and get a small brass or plastic adapter to mate the bug fuel line (smaller) to the FI fuel lines (bigger).

Please post a photo of all of the FI parts you have and your bug engine bay.

http://ratwell.com/mirror/potts/index.html

[Stray Catalyst]

The engine is in, the fuel pump was already mounted in the front. I need to either get a manifold (the S shaped rubber one) and relocate the AFM, or finish jury-rigging the one I have, as the PO relocated the AFM to inside the cabin, for reasons that aren't clear.



This is the manifold I've made, which still needs fittings for two hoses.



I have the resistors, sensor, fuel lines, etc all hooked up. I'm left with a handful of wires, two (or more?) of which go to the coil or that area of the engine. I've hooked up all the things where it seems obvious how to connect them, but when I tried starting the motor I got no spark. I don't have a fuel pressure gauge at this point.

[Marc]

The FI harness is independent "afterthought engineering", which is why it doesn't show up on the diagrams of the main harness.
The ignition should still function the same as it does on a carbureted car; the only place where the FI system touches it is where the wire to the ECU connects to get a "trigger" signal from the points - Term 1 of the coil.

Once you have spark, next thing to check is the fuel pump operation. It receives power from the "double relay" while cranking (power to solenoid Term 50) or when the contacts inside the AFM close, which only happens when the engine's running and drawing enough air to displace the flap inside far enough (tip: shoving a long screwdriver down the throat of the AFM to hold the flap open should result in the fuel pump running...you can even drive it like that in a pinch, although it'll be rich at idle). So, any air leak between the AFM and throttle body can prevent the pump from running once the ignition switch is released from cranking.

[Jadewombat]

Two things I'd invest in are a push button starter wire and a noid injector test light if you don't have them already. Both should cost about $20 or so. You'll need these so you can check things at the back of the car. When you're ready to check some things, pull one of the injector plugs off and put the noid light in it. Hook up the push button starter switch, turn the ignition key to the first position, and operate the starter from the back of the car. The noid light will flicker if the ECU is on (getting a signal from the ignition coil) trying to fire the injectors, turn the fuel pump on, etc.

http://www.autozone.com/test-scan-and-s ... 48078_0_0/
http://shop.advanceautoparts.com/p/actr ... ote+switch