26-09-2012, 12:31 PM
I am trying to sort out a colleagues fault on his 03 1.9 hdi with a siemens 801A common rail, its a shaggy dog story so please bear with me.
The vehicle was bought with the fault and driven from birmingham to Cornwall with no issues.
The fault is that the engine will start from cold ok but once the engine has run, even for a matter of seconds it will not restart for approx 5 hours, when he collected the vehicle he left it running whilst refueling so no problem but once home he switched off and it would not restart.
I have carried out a pin to pin continuity test on the engine to ecu the wiring is all ok the connectors are in good condition and both the cam and crank sensors have been replaced with new ones. The injectors have been replaced due to out of limit leakback with good ones that have been checked for leakback - within spec. The HP pump has been tested using a blind pressure tool - 1350 bar so all is ok there. Using a dual trace scope cam, crank, rail, hp pump volume and pressure sensors and peizo injectors are showing ok. Rail pressure rises fast when cranking and when the fault is present it is only the injector pulse that is missing. Performance and economy is good with no smoke present at all. I then was guided down the ecu route by a contact that felt it was getting into a loop that prevented a restart, however I am beginning to suspect that its perhaps the immobiliser that is the root cause but I cannot find a wiring diagram showing how the ecu is connected to the immobiliser - which pins and when etc. Any advice will be gratefully recieved.
The vehicle was bought with the fault and driven from birmingham to Cornwall with no issues.
The fault is that the engine will start from cold ok but once the engine has run, even for a matter of seconds it will not restart for approx 5 hours, when he collected the vehicle he left it running whilst refueling so no problem but once home he switched off and it would not restart.
I have carried out a pin to pin continuity test on the engine to ecu the wiring is all ok the connectors are in good condition and both the cam and crank sensors have been replaced with new ones. The injectors have been replaced due to out of limit leakback with good ones that have been checked for leakback - within spec. The HP pump has been tested using a blind pressure tool - 1350 bar so all is ok there. Using a dual trace scope cam, crank, rail, hp pump volume and pressure sensors and peizo injectors are showing ok. Rail pressure rises fast when cranking and when the fault is present it is only the injector pulse that is missing. Performance and economy is good with no smoke present at all. I then was guided down the ecu route by a contact that felt it was getting into a loop that prevented a restart, however I am beginning to suspect that its perhaps the immobiliser that is the root cause but I cannot find a wiring diagram showing how the ecu is connected to the immobiliser - which pins and when etc. Any advice will be gratefully recieved.
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alut:
