Hey all, so my 545/1000 has been messed with electrically by the previous owner and I've run into a problem. When I crank the car I get spark but fuel is not being pumped. MPI relay is clicking, mpi fuse is not blowing, and I can even hear my pump working but no fuel (yes tank has fuel and battery is good) what I want to know is a walk through on how to properly and safely rewire the pump. I'm new to fuel pumps so details would be great! Or a link on how to.And any suggestions would be appreciated. I have a walbro 255. Also just curious is the stock mpi relay really needed or is there a way to separately set the fuel pump up. Again I'm new to this subject.

I could tell you how it is done, but if you want a walkthrough with pics, it has been done here. click

First pic is not a re-wire at all. it's just a wire loop. No relay present.
Wonder why they did that hackjob in the first place?

4th and 5th pics show the main 12v wire hooked up directly to the MPI relay. It takes that route in the stock schematic too. But that wiring does look a bit bogus.


Hope this info helps you along the way.

Almost bought that vr4. The thing that scared me the most was the amount of wiring that needed done. Good luck with it

Thanks guys, yea I will take the pump out tomorrow and check it out, any other really important wires from the mpi fuse that are needed for making the pump work, the pump was making sounds but not sending fuel. Maybe I'm not getting enough volts, I'll check that tomorrow also.

If you hear the pump working than you should check fuel pressure and make sure the injectors are getting signal to fire.

^+1^ I'd test the pump on the bench, if you can hear it running but nothing is coming out up front I'd suspect either blockage or faulty pump.

Do you think the polarities were switched and the pump is running backwards?

Took out pump. Fuel tank is clean and plenty of fuel but I noticed the wire to the walbro has a burn mark. Def looks like it should not be there ha. What do you guys think? The power and ground wires are extremely stiff too ( I did have a battery problem recently I had a ground not connected in the front and it burned off my female terminals to the battery posts, maybe during that it fried this wire)

Now that you have the pump out make sure to do a proper re-wire. /ubbthreads/images/graemlins/smile.gif
It takes like 30 minutes to complete.

Tank is looking good though.