Grit Valve
2000 4.6 Vouge
Bad uneven tick over running issues check it hasn't come loose,your going to need a diagnostic on it or a spare working one to test .
awillemsen
Active Member
Here are the symptoms I experienced:
1) Revs would sometimes drop and then surge when waiting at traffic lights
2) Car would sometimes hesitate when accelerating
3) Car refused to start once (engine would turn over OK but not even attempt to fire) and then started fine after 20 mins wait (when breakdown man came!)
1) Revs would sometimes drop and then surge when waiting at traffic lights
2) Car would sometimes hesitate when accelerating
3) Car refused to start once (engine would turn over OK but not even attempt to fire) and then started fine after 20 mins wait (when breakdown man came!)
Grit Valve
2000 4.6 Vouge
Did he not plug his laptop in ?Could me maf best get it plugged in somewhere for best results or ask on here for some one local to you with a diag tool .
awillemsen
Active Member
In my case, the MAF had recently been replaced, so I knew it wasn't that (MAF never caused the drop and surge in revs). A new crank sensor fixed the problems. And the breakdown man was useless - told me it was probably spark plugs.
rewmer
Well-Known Member
Crank sensors dont "work a bit" they will either work or not. It is possible for them to fail when hot as they expand and not allow the engine to start and then work again as they cool down. What is more likely is a bad signal from the stator tangs on the flywheel. Bent tangs will give a spurious signal leading to all kinds of hickups. Easily tested with a scope though.
Grit Valve
2000 4.6 Vouge
Or loose
jt_armstrong
Well-Known Member
You have it spot on. When mine failed it gave the same symptoms as a failed engine coolant temp sensor I.e. difficult to hot start. I had it on a test book twice and on both ocassions no faults were diagnosed. Eventually it gave up altogether which made diagnosis easier. When I removed it the sensor tang was bent. Not sure what caused it though.
