wont start help
- Thread starter ed325i
- Start date
Does the tacho bounce?
No = crank sensors
Yes = DME relay?
1st checks
No = crank sensors
Yes = DME relay?
1st checks
peanut
Active member
if you have a spark then the DME relay must be providing the ECU with power so the DME relay must be working, at least in part.Also the crank speed sensor must be working also .
Check the fuel pump fuse ( I think fuse No32 but double check )
Has the petrol tank has been left very low ? top up to at least 2-3 gallons to give the pump some head and allow it to build pressure
Does the engine turn over at a minimum of 200+rpm ?
if it doesn't the ECU will prevent the fuel pump working by not earthing the DME relay . If the engine turns over slowly try jump starting or charging battery .
Try removing the DME relay and replacing it with a 3x way bypass cable. Search on here for 'no start' etc for details or go to Clarkes Garage workshop manual for an explanation.
Basically you connect together 3x wires with male spade connectors on the ends.
Remove the DME relay and replace it with the 3x way bypass in the correct order.
Put one connector in terminal 87 the second in terminal 87b then the last spade connector in terminal 30 which is constantly live even with the ignition off. Be careful !
This will cause the fuel pump to run continuously which you should hear .Try starting
If you have 12v+ at terminal 30 and don't hear the pump then you have a fault with one of the following.
1) The pump fuse,
2)the 12v+ supply terminal 30 to the pump fuse.
3) The 12v+ supply from pump fuse to the pump,
4)the pump earth
5) the pump itself.
If the pump works and you have a spark check you have fuel on the spark plugs after cranking the engine . If not look at the injectors and the injector circuit. if the tank was run low when the car was last used the pump may have pumped some water from the bottom of the tank into the fuel system blocking the injectors or the injectors solenoids could be sticky
Check the fuel pump fuse ( I think fuse No32 but double check )
Has the petrol tank has been left very low ? top up to at least 2-3 gallons to give the pump some head and allow it to build pressure
Does the engine turn over at a minimum of 200+rpm ?
if it doesn't the ECU will prevent the fuel pump working by not earthing the DME relay . If the engine turns over slowly try jump starting or charging battery .
Try removing the DME relay and replacing it with a 3x way bypass cable. Search on here for 'no start' etc for details or go to Clarkes Garage workshop manual for an explanation.
Basically you connect together 3x wires with male spade connectors on the ends.
Remove the DME relay and replace it with the 3x way bypass in the correct order.
Put one connector in terminal 87 the second in terminal 87b then the last spade connector in terminal 30 which is constantly live even with the ignition off. Be careful !
This will cause the fuel pump to run continuously which you should hear .Try starting
If you have 12v+ at terminal 30 and don't hear the pump then you have a fault with one of the following.
1) The pump fuse,
2)the 12v+ supply terminal 30 to the pump fuse.
3) The 12v+ supply from pump fuse to the pump,
4)the pump earth
5) the pump itself.
If the pump works and you have a spark check you have fuel on the spark plugs after cranking the engine . If not look at the injectors and the injector circuit. if the tank was run low when the car was last used the pump may have pumped some water from the bottom of the tank into the fuel system blocking the injectors or the injectors solenoids could be sticky
peanut
Active member
if you had fitted the 3x way bypass as i suggested it would have told you definitively whether the DME relay was faulty or not. There may still be a problem with poor earthing for the ECU and DME relay
Why don't you test the Engine temperature sensor before replacing it. It could become very expensive just replacing lots of stuff hoping for a solution. [
]There is very little information to go on but if the car is now running normally when the engine is warmed up, then it sounds like your cold start mechanism is not working correctly .It would be better to do a systematic check of the cold start components
Posts made and opinions expressed are those of the individual forum members
Use of the Forum is subject to the Terms and Conditions
