Hello,

New to the site and having starting problem. Engine will crank and fuel pump is running. Any ideas?

 

Mmmm, a 6ltr.

I have only ever seen 1, they are rare down here.

Lack of spark is my first best guess. Remove a plug lead, fit a spare spark plug in the end, and earth the plug casing on something nearby, crank the engine, observe spark or no spark.

No spark would be coils, igniters, wiring, or something, but for both circuits to fail would be odd at best. This leads to CAS, see below.

If you got spark, then injector pulse is suspect, and there I am blind, sorry.

There is a CAS (crank angle sensor) mounted on the timing cover. It would be the first thing I would suspect. The 5.3 Marelli engines (yours in Marelli also), had a sensor wire running down the LH side of the front area of the engine, and it has a joiner just below the oil cap area, and that joiner creates havoc on the 5.3, so maybe the 6ltr is the same, I simply did not look at the time.

There is also another sensor down the back, in behind the oil filter, mounted on the bellhousing flange, on the LH side. No idea of its control circuits, but again, maybe its got a cruddy joiner in the general area??.

 

Thank you for the tip I will look at the joiner in both areas.

 

Hi, my best guess would be the CPS (Crank Position Sensor) it's a really common fault. It seems to occur mostly around 100,000 miles but it isn't unusual for it to go at any time. A new one is usually the best fix, although it is possible to take the old one off and use a wire brush to clean the tip. If you take it off and discover that it's black rather than a gold colour it's probably the cause of your starting issues.

 

Usual tip, tach won't move if the CPS is bad. Otherwise you'll get a couple hundred rpm while cranking.