Technical Fuel pump primes but doesn't run when engine on?

[Dan Solo]

Hi all,

My 06 panda active has had a very colourful life and a while back had a 1.2 Punto engine replaced the original 1.1 engine (many years/miles ago).

During the wild storms a month ago it ended up driving over a tree that landed just in front of me which among things ripped the whole exhaust system away from the braided flexible bit at the front. Engine was still running fine for the 2 mile drive home but then conveniently died right at my gates. Thought fueling issue right away but next morning started fine albeit now sporty sounding with no exhaust.

Drove about 4 miles then it cut out, could hear it prime with the key and it started again no problem. Died after the next 3/4 miles.

I've checked the inertia switch below the seat and pushed it in but I don't think it triggered with the tree incident. Replaced the relay in the engine fuse box for the pump.

Anyone any ideas?

 

[koalar]

Do you have a scantool to read the rpm

I take it your active do not have a rev counter

 

[Dan Solo]

No scan tool and no rev counter unfortunately. I can prime the engine no problem on start up so the car will idle fine until I assume it runs out of whatever fuel was sent up to the engine at the start

 

[koalar]

No scan tool and no rev counter unfortunately. I can prime the engine no problem on start up so the car will idle fine until I assume it runs out of whatever fuel was sent up to the engine at the start

Nope

Fuel primed only lasts a few seconds

The fuel rail does not hold it pressue

If you can hear the pump prime the circuit and command from the ECU are all working properly at that moment in time

4 miles is quite a long way around 10 minuites I guess

Does it stop suddenly
Does it cough to a stop
Does it restart on the first retry

 

[jrkitching]

4 miles is quite a long way around 10 minuites I guess

That's also the time when it will have warmed up and is switching to closed loop fuelling. Coincidence, or maybe not?

 

[Dan Solo]

Does it stop suddenly
Does it cough to a stop
Does it restart on the first retry

Hmm it kind of just....stalls mid driving so starts to engine brake with no fuel, if you try to crank the engine or bump it while still moving it won't start, but once pulled over and cycle the ignition key a few times it starts on the button.

I managed to commute the 25 miles into work like that

No dash warning lights or anything. Had the rear seat up giving the fuel pump a few whacks for good measure.

 

[koalar]

Hmm it kind of just....stalls mid driving so starts to engine brake with no fuel, if you try to crank the engine or bump it while still moving it won't start, but once pulled over and cycle the ignition key a few times it starts on the button.

I managed to commute the 25 miles into work like that

No dash warning lights or anything. Had the rear seat up giving the fuel pump a few whacks for good measure.

Almost certainly not the fuel

They nearly always splutter a bit before cutting out

When it cuts out there should be an oil and battery warning?

 

[koalar]

Next time it stops

Just switch it off

Pull the quick connector and direct it into a bottle and switch the ignition on

 

[koalar]

I had a pump fail, it would cut out randomly, but you can't hear it prime straight away, if you can hear it prime but not start first turn of the key it's in my opinion unlikely

If you do change the pump yourself you will probably need to fabricate a tool or buy one, the top of the tank swells up making it very tight

It's Obviously under the car at the back and could get a knock

Lots of parts fail in different way giving different symptoms, which is why it's best to confirm a failure before the hassle of changing parts

You can't hear the noise of the pump while the engines running. It's more noticeable with the rear seats removed

The cars not going to run 100% without an exhaust

I broke the CAT off at the back, it does mess up the fueling slightly, it runs rich, uses more fuel than it should but still ran fine and did not cut out, I swear it was faster but more likely in my head as is sounded faster

It does have oil and oil pressure I take it. A small knock to the sump can cause all sorts of problems

The symptoms are the same as a faulty crank sensor, it is at the very bottom of the engine, Drivers side

One of the common faults with these is the engine cuts out when warm and will not restart, once cooled down a bit it starts again

The normal way to diagnose these is as it fails look at the rev counter as it fails or on a scantool

This isn't an option here, but no rpm signal equals no spark,

 

[Dan Solo]

Thanks for the input Koalar. The panda has been parked up at work for the last 3 weeks as I gave up hope for it. To make the situation more annoying, I went to get it this morning and it started up fine today and drove the 25 miles home without any problems!

 

[koalar]

They don't normally fix themselves

With the engine running, be careful, stay safe

Inspect and gently wiggling a few wires and see if it stops

Earth lead under the battery tray
ECU
Lower O2 sensor
Crank sensor
Would be a good start

 

[Dan Solo]

Got a scanner hooked on, panda was ticking over fine while getting this info. Seems like the two O2 sensors were giving me decent enough voltages.

The revs settled down to 780rpm after a few minutes of idling.

Wondering if it's either a dodgy earth lead or a duff coil pack.

 

[koalar]

Cool

Some good data


Ignore the P03??

They tell us there is a problem but not what it is


-40 on the coolant sensor
And
Post CAT single dropping out must be diagnostic


I take it was running fine before the tree

 

[koalar]

P0115 is a very common error

Start the car from cold

Grip the top hose

The bottom of this hose should remain cold for a good couple of minuites