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At work we have a 1.9 diesel Alfa 159 that has a intermittent no start problem. When you turn on the ignition there is no check engine light nor will it start, then anything from a few seconds to few a mins the engine light appears and the car will start. Its not my job but I wondered what could cause something like this. I offered to help the guy at work so we did some basic power and ground checks at the engine computer which checked out ok. The only problem I could see was the computer was taking longer than usual to earth out the main ignition relay. Sometimes a few seconds sometimes a few mins. Sometimes the voltage on the earth would be 0.2v but other times would be 0.96v with the ignition on. I can only think the computer maybe faulty but would like to know if there would be other inputs the computer needs that maybe missing such as some sort of signal from the body computer? What else can be checked out here? There is a old CAN bus code stored but that is it.
hi sir you mentioned the check engine light is intermittent i would look at your crank sensor signal to the computer and do it through all ranges of rpms and check for dropouts if you have checked all the basics this might give you some direction i would do a wiggle test while looking at crank signal i hope this gives you better direction with out a steady strong crank signal the engine will drop out
chief eaglebear wrote: hi sir you mentioned the check engine light is intermittent i would look at your crank sensor signal to the computer and do it through all ranges of rpms and check for dropouts if you have checked all the basics this might give you some direction i would do a wiggle test while looking at crank signal i hope this gives you better direction with out a steady strong crank signal the engine will drop out
Sorry forgot to mention this is happening without cranking, it happens in the Key on engine off state. If the engine light is on then the car starts fine and runs fine until turned off next. So with key on the engine light will not be on, then all of a sudden a few mins or secs later the engine light appears and you hear the relays click etc. Also the computer still communicates, 5v ref present, 12v at engine computer even without check engine light.
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