Aftermarket EFI Accessory Hardware

[Blue MK3]

I'm exploring the idea of installing one of the currently available EFI systems. In looking over all the tech info and speaking to reps, two common issues surface. That is, all systems require an O2 sensor in the exhaust and the external fuel pump must be mounted below the fuel tank. That presents two potential problems for me.

First, the O2 sensor needs to be mounted into the exhaust pipe several inches after the four header pipes join AND must be mounted at least 10 degrees above the horizontal (nine o'clock and three o'clock). On my MK3, the sidepipe is only about 1 1/2" away from the body and the fatter muffler section is even closer. Given that the total length of an O2 sensor with attached bung/wiring/fittings appears to be over 2" long and I can't angle it down to clear the body, how can a sensor be mounted? Cutting a hole in the body at the appropriate mounting location would involve extending it into either foot well.

Second, the bottom of the fuel tank on my car is well below the body in the rear and there doesn't seem to be any point to mount an external pump without dangling it perilously low. I guess I could spring for an internal pump, but was hoping to avoid the extra trouble and expense.

Anybody out there been through this type of installation? Your thoughts and/or suggestions are welcome.

[Bob Cowan]

Mounting the sensor into the collector is not that difficult. Mine is at about the 4 o'clock position. I did have to notch the body a tiny bit, about 1/4". I could have moved it down a bit, but I wanted it tucked up into the chassis a little better. You can see it if you stand right next to the car and look down between the body and side pipe.

I'm using an Aeromotive fuel pump. It's mounted to the X frame, behind the IRS pumpkin. That put's it about in the middle of the fuel tank. Seems to work just fine there.

[Blue MK3]

Thanks, Bob. I'm still not sure on the location of the O2 sensor. As I said, if I cut the body at the proper location for the sensor, it will come into a foot well. If I mount it forward so it would enter the engine compartment, it would be collecting information from only one cylinder. As far as the pump location goes, I can always go to a submersed unit in the tank. That's recommended anyway, as it keeps the pump cool.

[jsup]

Don't worry about clocking it to any particular position. More important is that it is past the individual pipes, and into the collector. You can get a bung welded in at almost any exhaust shop. They have a punch that makes the correct size hole then they weld it in.

Also, it does not matter if it goes in the passenger or driver's side of the engine. Either side will work.