car starts then stops

[mike brewer]

hi all,

Carrying on from my earlier problems with my car starting and then stopping. After I pulled out some relays on ths fuse board. I had an Auto electrician look at the car today and he informed me that one fuel pump relay was not working correctly. He has bi-passd that relay and the car started and ran ok. After he left, ten minutes later, the car refused to start again. The Fuel pump does not appear to work at all. So, the engine turns over and will not fire.
I still feel that it may be the fuse board causing problems.

Is it possible for the fuseboard to be tested by the electrician?

Is it safe for it to be left by-passed?

Cheers, please help.

[jchase]

If you have a 280i , you didn't say what engine , but if you do, then bypassing the fuel safety cut-off will energise the thermo time switch at the same time as the fuel pump. This makes it really difficult to start the car from cold, unless you keep the ignition off until you try to start the car - i.e the worst thing you can do is get in, turn the ignition on, and wait a few seconds before trying to start the car - the time switch energises, and you no longer have any benefit from the cold start fuel injector.

Hope this helps.

-Jim

[350zwelgje]

Had the same symptoms with my 350i, and it was the coolant temperature sensor. You can check the sensor as described in the bible. A temporary fix can be to shortcut the wires of the sensor (ECU thinks engine is hot) to get home.

Rob

[jchase]

I just remembered, I had this problem on a previous Alfa - car starts from cold, then dies about 5 seconds later. The plugs were black when removed immediately after the die, so the conclusion was the cut out was due to overfueling. Turned out the fuel pressure was too high. I guess a broken coolant sensor would also cause an over fueling cut out in the same way, once the engine warmed up, after say 2 minutes ?

Keep us posted ...

-Jim

[dickymint]

350zwelgje said:

Had the same symptoms with my 350i, and it was the coolant temperature sensor. You can check the sensor as described in the bible. A temporary fix can be to shortcut the wires of the sensor (ECU thinks engine is hot) to get home. Rob

Even better is to short it out with a 170 ohm resistor which tells the ecu its normal temp.
However i think Mike said he had changed the sensor not so long ago. (dont rule it out though Mike).
PS did you change the coolant sensor or the thermotime switch?

[redwedge5]

[quote=dickymint]

Even better is to short it out with a 170 ohm resistor which tells the ecu its normal temp. [quote]

I wouldn't have had a clue about what you are talking about if you hadn't uploaded the EFI system PDF on the maintenace section What a very readable document even for us mechanical simpletons