I had an issue with my 8V MPI where it wouldnt start, speed sensor replaced and still didnt start.

So got the multi-meter out and with the help of Chris and the PDF's on the net started to track it down.

Fuel pump was not starting at all. So stripped the dash out (Worst setup I have ever seen for relay location) and found two relays, No 18 which is starter motor and relay 167 for the fuel pump.

Did the tests in the PDF and turns out the relay could be naffed as joining the big red wire with the big blue and yellow wire the fuel pump fires and the car starts. So went out to get a new relay. Which sorted my issue till tonight.

Car broke down again and AA bridged the blue/yellow and the red and again it fired up. But on pressing the brake pedal it would staff out. So where to go from hear?, is this a common thing with these cars?.

If somebody could tell me what the 4 wires do and where they connect that would be a help. I assume the thick red on is the constant supply to the other big red ones and the blue/yellow is the load or feed wire to the fuel pump. But what does the black/(other colour/was dark out) wire do and the other small green/(other colour wire) do and goto. Or is something else the fault with it stalling when pressing the brake pedal. No additional lights are lit up on the dash mind and all go out as they should.

Any help would be great as these realys are not cheap.

Is it a small press on the brake? (Could be an electrical issue related to brake light switch/lights coming on). Or when the pedal is depressed more fully? (Could be related to intake pressure level).

According to the wiring diagram I have...

Black - terminal 86 on relay - 0.5mm cross section (thin) comes from the ignition switch

Blue/Yellow - terminal 85 - 0.5mm cross section (thin) goes to a brown 6 pin connector at the bulkhead, and eventually terminates at the Simos ECU in the engine bay.

The above two wires cause the relay to activate, connecting the below two wires

Blue - terminal 87 - 4mm cross section (thick) comes from the fusebox (positive supply)

Red - terminal 30 - 4mm cross section (thick) not looked up the page the one I am looking at refers to but it almost definitely goes to the fuel pump

I'm not sure what can cause relays to blow. One possibility is if the relay is used to deliver more current than it is designed to provide. As you cannot force feed current (a device will only take what it uses) I would suspect an issue with current draw from the fuel pump, and a fault there. Although I'd have thought it would blow the fuse first?

The blue and yellow wire is dead. Still the car stalls when the brake is pressed even with the black/green wire disconnected which goes to the ecu. The lights work, well the passanger side bulb has gone but the drivers side works and it does not make a diffrence on pressure. If you tap the brake it still stalls.

I did find crossing the black/red and wire on the far right of the brake switch connector got the fuel pump going with the ignition off.

Where is this connector at the bulkhead and is it easy to get to?

I am suspecting now its the ecu as the auto electrcian said, he said there cheap and nasty and it only takes a small voltage surge to damage it, but I suspect he could be right.

How do you go about changing the ecu?

Would I be able to cut the wires on the car that goto the brake lights and wire a new set in just to light the brake lights on a simple on/off circuit or would that cause other issues.

Edited 20 October, 201114 yr by sejin999