Ghibli 2.0 cutting out

dt95aac

Junior Member
Messages
68
I have a strange problem in my 2.0 Ghibli with electronic ignition, it has been randomly cutting out.

When on the highway it will get going again after a few seconds and when stuck in traffic it will restart instantly on the starter.

It happens randomly usually after at least 30 minutes of driving, when the car is in normal operating temperature.

All gauges are in the correct operating range when this happens (temp, oil pressure, battery voltage)

When it does it on the highway (so engine still turning) there are no signs of an electrical fault, ie no dash lights, all electrics working properly and when it's not cutting out it has good power and smooth operation.

The fuel pump and filter are 2 years old, but the car has been sitting (albeit with a full tank of fuel) for the best part of the last year.

I have checked all earthing points, cleaned and swapped the relays in the engine bay and the battery is new.

Could this be sensor related in a way that would not trigger any dash lights, or should i start investigating the fuel system?

Alex
 

Oneball

Member
Messages
5,511
If it cuts out straight away with no spluttering I’d be looking at ignition not fuel. Is there a crankshaft position sensor on the Ghibli?
 
Reactions: Zep

dt95aac

Junior Member
Messages
68
The Ghibli has two ecus and two of every sensor, apart from the throttle pot and the idle valve.
Essentially each bank of cylinders is operated as a separate engine, so failure in a signle sensor would cause the engine to loose power and run uneven as one bank would still work, but it would not die.

Hence I am inclined to believe that whatever it is must me able to affect both sides of the engine.

I will look into the fuel pump wiring and connector as i've been told these fail and into the circuit that powers the ecus.

Any other suggestions are welcome.
 

conaero

Forum Owner
Messages
31,592
TDC crank sensor or fuel pump relay is where I would start.

Find the fuel pump relay and swap it with a similar one say the cooling fans and give it a whirl first, then the crank sensor and go from there.

Also check the engine earth (run a second one) and battery terminals for tightness.

Quick cheap and easy things first before you go deeper.
 

Wally

Junior Member
Messages
152
Crank-sensor I suppose..... You don't have a specialist around to read DTC? (fault codes)
 

dt95aac

Junior Member
Messages
68
Thanks, relays and engine earths have been checked and swapped.

Fuel pump is next on my list.
 

dt95aac

Junior Member
Messages
68
Crank-sensor I suppose..... You don't have a specialist around to read DTC? (fault codes)
As mentioned above the Ghibli has two crankshaft sensors and two ecus, it is highly inlikely that both are failing at the same time.
If only one is malfunctioning the engine will not stall.
 

Maurizio

New Member
Messages
27
I had the same issue on my 2.24v. Exactly the same symptoms, which made me think it looked like a resync of the ECU to the engine phase (crankshaft and camshaft sensors). I'm an engineer and I worked for Marelli on ECU software for a few years, so I sort of knew what to look for. That, and the fact that the issue came about after I had removed the sensor to repaint the engine head covers.
And in fact, the camshaft sensor distance from the cam teeth was out of specs. It is a magnetic sensor and it must operate within specs as far as the air gap is concerned.
What happened was this: the ECU only needs the cam sensor at start to discriminate between the two 360° cycles that the engine's 720° intake-compression-combustion-exhaust is made of. Once the engine is up and running, you could in fact disconnect the cam sensor, as the crankshaft sensor is enough once the phase is known. However, a randomly working cam sensor makes the ECU believe that synchronization with the engine's phase is lost, and that a new synchronization must be done. This means basically restarting reading the cam and crankshaft signals from scratch, and in the meanwhile the engine goes off if you're at the traffic light. If you're running, odds are that after the cut out, the engine will restart.
I'd check the air gap of both camshaft and cranckshaft sensors, in the 2.24v the air gap should be between 0.7 mm and 1.1mm, manual page is attached. Note that in general there's a shim under the camshaft sensor case, for this reason. Maserati supplies 0.2mm shims if needed.
 

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