cheekystallion
New Member
- Posts
- 5
- Location
- Rochester, Kent
Hi all, I'm new on today - fantastic forum!
Wonder if anybody could shed some light on this one for me...
Started having some problems with my Disco recently whereby I went out one morning to start the car as usual and after waiting for the glow plug light to go out as I always do, I noticed the bugger wouldn't start. I held it over on the key for about 5 seconds and after a second or so of running lumpily she ran fine. Sounded like a classic glow plug fault, but after proving that the glow plugs were fine I found myself on a long journey of under bonnet familiarisation.
Now this is where I cut a horrendously long story very short. I've narrowed the fault down to the fuel timing solenoid (and / or its associated control) on the fuel pump, the proof of this being as follows:
There is a 3 pin plug connecting to the main wiring loom next to the fuel pump. One wire is a +12V to the fuel cut off solenoid and the other two are the +12V and 0V to the fuel timing solenoid, the 0V going back to the ECM.
If I disconnect the 0V wire to the timing solenoid, she starts fine straight away. She also drives perfectly but the ECM cops the arse after a while because it must know I've unplugged something and then goes into limp home mode. With the sensor plugged back in, starting is a pain in the bum followed by perfect running. Incidentally, I have firmly eliminated the possibility of the fuel system losing prime or air getting in.
I've reached the conclusion that the timing solenoid either isn't doing what the ECM is asking it to do, or the ECM isn't asking it to do it properly. So its new fuel pump or new ECM I think?
I've now reached an obstacle in my fault finding trauma in that I am unable to test any further because I don't know what SHOULD be happening.
Does anybody know how the fuel timing solenoid works? When should it work? Is it a simple on / off device or does it vary its function according to engine running conditions. I've measured the current through the thing during starting and running and it seems to function during the first few seconds of running and then switches out. Is it simply a starting aid or does it operate during driving too? What engine conditions does the ECM consider when making an adjustment through this solenoid i.e. could another sensor be confusing issues?
Most importantly though, I would appreciate a kick in the right direction if anybody can suggest anything else.
Any light you could shed on this would be much appreciated!
Thanks
Chris
Wonder if anybody could shed some light on this one for me...
Started having some problems with my Disco recently whereby I went out one morning to start the car as usual and after waiting for the glow plug light to go out as I always do, I noticed the bugger wouldn't start. I held it over on the key for about 5 seconds and after a second or so of running lumpily she ran fine. Sounded like a classic glow plug fault, but after proving that the glow plugs were fine I found myself on a long journey of under bonnet familiarisation.
Now this is where I cut a horrendously long story very short. I've narrowed the fault down to the fuel timing solenoid (and / or its associated control) on the fuel pump, the proof of this being as follows:
There is a 3 pin plug connecting to the main wiring loom next to the fuel pump. One wire is a +12V to the fuel cut off solenoid and the other two are the +12V and 0V to the fuel timing solenoid, the 0V going back to the ECM.
If I disconnect the 0V wire to the timing solenoid, she starts fine straight away. She also drives perfectly but the ECM cops the arse after a while because it must know I've unplugged something and then goes into limp home mode. With the sensor plugged back in, starting is a pain in the bum followed by perfect running. Incidentally, I have firmly eliminated the possibility of the fuel system losing prime or air getting in.
I've reached the conclusion that the timing solenoid either isn't doing what the ECM is asking it to do, or the ECM isn't asking it to do it properly. So its new fuel pump or new ECM I think?
I've now reached an obstacle in my fault finding trauma in that I am unable to test any further because I don't know what SHOULD be happening.
Does anybody know how the fuel timing solenoid works? When should it work? Is it a simple on / off device or does it vary its function according to engine running conditions. I've measured the current through the thing during starting and running and it seems to function during the first few seconds of running and then switches out. Is it simply a starting aid or does it operate during driving too? What engine conditions does the ECM consider when making an adjustment through this solenoid i.e. could another sensor be confusing issues?
Most importantly though, I would appreciate a kick in the right direction if anybody can suggest anything else.
Any light you could shed on this would be much appreciated!
Thanks
Chris
