19 replies to this topic

[Sprocket]

Description of the relay pack control.

Coil side of relay pack (small connector)

+ve supply to the relay coils

The main relay is permenantly supplied with 12v (internal), the fuel pump relay is supplied with 12v from the IGN position on the key switch (white), the manifold heater relay coil is supplied with 12v when the main relay is energised (internal but common to brown pink), the starter relay coil has two options depending on year. One, the starter coil is supllied with 12v when the key switch is turnd to CNK (white with red). Two, the starter coil is supplied with 12v when the key switch is turned to CNK (white with pink). Note the latter, the wire from the starter switch is white with red, then changes to white with pink through the body to engine loom connector.

-ve supply to the relay coils.

The main relay is grounded by the ECU (white with pink), the fuel pump relay is grounded by the ECU (black with purple pin1), the manifold heater relay is gounded by the ECU (black with pink), the starter relay has two options depending on year. One, the starter relay is grounded (black pin4). Two the starter relay is grounded by the alarm ECU ( white with red). Note the latter, the wire from pin4 of the relay pack changes from white with red to white with pink, through the body to engine loom connector.

Main switched power supply (large connector)

All four relays are fed with 12v from the battery (brown). Main relay switched live is brown with pink. Fuel pump switched live is brown with slate(grey). Manifold heater switched live is brown with blue. Starter switched live is brown with red.


Logic explained

When the key switch is turned to IGN 12v is supplied to the ECU on a white wire this powers the ECU. The ECU will then initiate the fuel pump for 10 seconds and then de activates it again if there is no further activity. Turn the key to CRK the starter is initiated (if the imobiliser/alarm is off, where fitted). Activity is recorded by the ECU on the Crank Position Sensor. The ECU then initiates the Main relay. This provides power to the ignition coil, stepper motor, purge valve solenoid, and ECU directly on the brown pink, and the injector via the ECU. The engine should now start. Once the RPM is above a predetermined RPM the manifold heater is initiated until the coolant temp measures 75c or more it is then de activated. The Main relay, and fuel pump relay, are the only ones to be energised when the engine is running and fully warmed up.







Now if you are saying that the fuel pump and ignition coil are loosing its +ve feed then i personaly would be looking at one of two things, the ground point for the ECU or the ECU itself. The ground point being the favourite.

Before condemming the ECU be VERY sure that you are infact loosing the +ve feed to the all the components fed by the brown pink/ brown grey wires,that the ECU ground point is intact and in Excellent condition.

It may be simply a broken wire or loose connection on the power distribution from the starter motor/ battery. Not unlikely but not very common. Unfortunately no amount of discussion will diagnose this unless you test it with a digital volt meter.

Hope that might help. I'll be putting that in a post in itself as i do think it could be useful information

[BoyracerAU]

Draggin up old threads in the hope that someone might know what solved this riddle. The problem seems to be exactly what my car's doing at the moment.

Does anyone know what fixed it for The Dodge?

Even better, if anyone's in the district of Wirral, maybe you know Roger? If you get an opportunity, I'd be grateful to find out how he sorted it out.

[yubyub]

Any news on the whining pump too?

[NudgerSS]

Any news on the whining pump too?

I had a spot of bother with my Spi and intermittent fuel supply. After finally conking out and the AA bloke very graciously spending an hour trying different things it all came down to a faulty connector on the wedge of inline fuses above the injection unit. Sweet as a nut after that.

Just a thought...

[baggy33minis]

dragging up this old thread because this is the problem with my mates spi.It describes the fault perfectly.Do we have a cure?