Technical ENGINE JERKING WITH NO POWER

[Euan2002]

Hi,

I probably drive my car once a week and in the last 2 weeks I’ve been having a problem where when I drive my car for the first time after a while as soon the car has to go up hill or put under a low amount of pressure at a low speed it loses all power and the engine starts to jerk and it cuts out. Even after letting it idle it jerks and shudders. I am not sure what is causing the car to lose all acceleration as there is no check engine light on. This is after both a cold start and letting it get to temperature. What is causing the issue? Any ideas?

I read somewhere it could be a fuel pump? The temperature has dropped quite a lot recently could it be that?

 

[varesecrazy]

Hi,

I probably drive my car once a week and in the last 2 weeks I’ve been having a problem where when I drive my car for the first time after a while as soon the car has to go up hill or put under a low amount of pressure at a low speed it loses all power and the engine starts to jerk and it cuts out. Even after letting it idle it jerks and shudders. I am not sure what is causing the car to lose all acceleration as there is no check engine light on. This is after both a cold start and letting it get to temperature. What is causing the issue? Any ideas?

I read somewhere it could be a fuel pump? The temperature has dropped quite a lot recently could it be that?

Hi,

No warning light..

Not related to a misfire (electrically) as that should give at least 2 error codes

A fuel supply issue is a possibility..

So, does this happen 100% of the time, or just occasionally?

 

[Euan2002]

Hi,

No warning light..

Not related to a misfire (electrically) as that should give at least 2 error codes

A fuel supply issue is a possibility..

So, does this happen 100% of the time, or just occasionally?

Occasionally, normally the first time turning the car on after a while. Happened last week but then the next ran perfectly. But has happened again tonight…

 

[Zardo]

If this car has hydraulic actuators (twinair) it could be an issue with this unit, however I would expect a fault code in this case. If one cylinder out of two stops working correctly, it is quite clear that the engine will shudder a lot before cutting out.

I had an issue like that with a four cylinder multiair, however the shudder and power loss was limited to a cold engine revving above 1500 RPM, and it would occur only after a distance typically ranging between 250 and about 2500 m. It never occured on an already hot engine and would not impede idling when the engine was started again.

Could also be a dirty injector, you could always try an injection cleaner first

 

[varesecrazy]

If this car has hydraulic actuators (twinair) it could be an issue with this unit, however I would expect a fault code in this case. If one cylinder out of two stops working correctly, it is quite clear that the engine will shudder a lot before cutting out.

See below for motor spec.

 

[varesecrazy]

It's a 1242cc motor.. Same as Panda and 500

 

[Zardo]

Yes, my fault, the twin air Punto would be 0.9 l and the multi-air would be 1.4 l. So it's the old 4 cylinder 1.2 l FIRE engine, right? Then ignore my post about the twinair/multiair issue.

A shuddering engine could be explained by one cylinder not firing as much as the others.

some ideas:

• injector problem (loose wire on one cylinder or dirty injector)
• ignition problem (loose wire on one cylinder, faulty wire, faulty spark plugs)
• compression problem (loose spark plug, less likely - happened to me on cylinder one after the garage changed the timing belt)
• timing problem (less likely)
• mixture problem
• fuel pressure problem

Check connections, check spark plugs, add an injection cleaner to the fuel, reset the ECU so it will be forced to re-learn

 

[GrandePunto PL]

Another boring thread (there is about 100+ like that, no need to start another one, just use Search next time).
And just another neglected car, zero maintenance. Plus not driving it regularly. Recipe for disaster.

Check basics, OBD2 (MES program), faults (some will not trip Check Engine), parameters (if they make sense: temperatures, pressures etc.).
Ignition system dwell (coil charge time - healthy coil operates under 2,0 ms, maximum is 2,5 ms).
Operation of VVT (check/clean solenoid valve, check OBD2 data, camshaft desired VS actual position).
Timing (VVT positions from 1 to 6, where "VVT1" should be around 106 degrees).
Valve lash/clearance - the most neglected maintenance item ever in the history of 8V FIRE family engines.
Fuel pressure (about 3,5 bar). Old spoiled fuel(?).
Sensors like crank and camshaft misbehaving - you need oscilloscope to properly diagnose them.
Leaky exhaust and/or old fouled lambda sensors can spoil the engine performance as well. Gas analysis would help (you can check it independently from MOT).