Technical Diesel Pump

[Kronkron]

After a quick bit of advice from those that are more technically minded than me.

After singing the praises of my panda never letting me down, it's let me down

Just purchased a new battery as the old one was 10 years old and it had a few missed starts I'm the cold and all has been fine for a few days when the panda suddenly stopped on the way home.

Can't hear the fuel pump priming or pumping so have checked the fuses and swapped over a couple of the relays but it's not brought any success.

Any suggestions of what to check and how to check before looking for a replacement fuel pump?

May or may not be related but the horn does not appear to be working either now.

Any advice appreciated before giving the garage all the Christmas spends

K

 

[koalar]

suddenly stop and will not restart
or chugged and spluttered then will not restart

 

[koalar]

D020 ENGINE CUTS OUT WHILST RUNNING (THEN DOES NOT RESTART) - Fiat - NUOVA 500 - eLearn - 4CarData

if you have a scanner reading the RPM and fuel pressure would be a Good start

 

[Kronkron]

Cheers @koalar will have a look through this in the day and once I have recovered the car back.

Wife's description was..... errrrr it just stopped! So not much help

 

[koalar]

Cheers @koalar will have a look through this in the day and once I have recovered the car back.

Wife's description was..... errrrr it just stopped! So not much help

as a general rule
splutters to a halt = fuel
stops dead = electrical

not 100% but you have to start diagnosing from somewhere

 

[Goudrons]

First thing is to check all the fuses and the main earthing points (battery to body and engine to body).
The straps can rust out.

There's two fuse boxes, one in the car and one under the bonnet. I think the horn one will be in the car.

You can check the rail pressure when cranking with a OBD tool, it should be around 200-300 bar. (20,000 to 30,000 kpa).
You can pick up cheap bluetooth obd dongles for a few quid and use something like the free version of Torq Pro on a smart phone from your app store.
If there isn't enough rail pressure there are various reasons why it might be low and they aren't all backwards of rail.

It could be HP pump or lift pump which are back from the rail, but it could also be failed injectors bleeding off rail pressure, leaks in the fuel lines or unions or air in the system from failed seals.

If you've a multimeter can you check the feed to the fuel pump has power at the pump's connector under the back seat with the ignition on?
(you could rig up a bulb tester if you haven't a multimeter).

You could also try jumping the pump with an external 12v source, see if it powers up, these should detect a dodgy lift pump.

Testing the hp pump and injectors are a lot harder, particularly if it isn't running, so I would suggest just checking them over for signs of leaks.
You might also want to check the fuel filter contents for water and swarf.

 

[DaveMcT]

A blocked diesel fuel filter can stop an engine running. Early signs are starting and tick over but reluctant to rev.

 

[Kronkron]

Cheers Gents

I'm going to order a fuel pump just in case that is what it turns out to be and it saves me waiting for another day or two - any recommendations on brand/supplier.

My gut feeling is that it's electrical/pump related as I can no longer hear it when turning on the ignition, Its my intention to try and do some basic checks to see where the electrical failure is to determine if it's the pump or something else. is this a sensible idea, to run a test lamp/multimeter at the connections to the pump?

sorry just realised that exactly what @Goudrons is suggesting thank you.

 

[koalar]

if driven over a pothole the inertia switch could have tripped cutting power to the pump ?

 

[RalphM]

Or a handbag or such bouncing about under the seat.

 

[DaveMcT]

Disconnect the fuel supply at the fuel filter and divert it to a container. The lift pump should run when you turn on the ignition and fuel should flow at a fair old rate. Flow rate should be similar after the fuel filter.

Fiat avoid change for it's own sake so much of the wiring in MJ will be the same as the petrol models. Last year, my 100HP did refused to start after it was parked for weeks during the Coof lockdown. Pulling and testing every fuse and relay in the car eventually sorted it but I never found the culprit (stuck relay maybe). In my case the OBD port was also dead. An issue I had not appreciated until I tried to connect a laptop and MES refused to work.

Maybe the MJ has similar wiring issues.

 

[Kronkron]

Well, the recovery driver has just cast doubt on my appraisal.

He felt it was turning over far too easy and there was no compression, therefore the timing chain had snapped and not to waste my time trying to chase down a fault??

If I could still hear the pump running I would be willing to accept that diagnosis given the wisdom of his experience, however, the fact I can't hear the pump running, and it has been a noisy blighter for the last 130k miles, makes me doubt his take on the situation.

I still think I'm best to look into the pump first, or is there an easy way to check the chain issue first?

 

[RalphM]

Press the brake a few time till all the vacuum is gone the pedal will go hard,
then turn the engine over for a few secs on the starter, if you then have some
vacuum back the cam chain is ok as it drives the vac pump via the inlet cam.
Or if you take the vac pump off you can see the end of the cam and see if it
rotates on the starter.

 

[koalar]

surely if the pump is normally noisy

And now it quiet it’s because it’s given up the ghost


Or am I missing something obvious



I would lift the rear seat and tap it with some wood. I’d be surprised if it didn’t kick back into life temporarily

 

[Kronkron]

That's where I'm coming at it from.

 

[Cinq999]

My fuel pump in the boot is loud, and goes on for a good 10-15 seconds.

Take the rear bench seat out, and make sure you're getting 12v to the pump to start with.

When you turn the ignition on, you will hear it easily with the seat out.

Another tip for checking the chain. On the top left of the engine head is the camshaft sensor (white/grey colour). Take out the bolt, and pull the sensor out.

You'll see the camshaft in the hole. Either crank the engine over and see if camshaft spins, or put it in gear and push it and have a look.

 

[koalar]

My fuel pump in the boot is loud, and goes on for a good 10-15 seconds.

Take the rear bench seat out, and make sure you're getting 12v to the pump to start with.

When you turn the ignition on, you will hear it easily with the seat out.

Another tip for checking the chain. On the top left of the engine head is the camshaft sensor (white/grey colour). Take out the bolt, and pull the sensor out.

You'll see the camshaft in the hole. Either crank the engine over and see if camshaft spins, or put it in gear and push it and have a look.

correct the beginning of this video explains

 

[DaveMcT]

No noise from fuel pump has me thinking the issue could be electrical. Mine was probably a relay but I'll never know for sure. It pays to have known good relay for testing.

Worst case is cam chain. I recently bought a 1.3 MJ with snapped cam chain. I'm budgeting around £400 in parts -

Cam chain kit - £100
Oil pump - £80
Set of 16 rockers - £120 BUT unless the chain jumped its likely that only four are damaged. Time will tell.
New sump - £30
Stuff (there is always "stuff" to fix) - £100
I have a 1.2/1.4 timing kit, so might not need one for the MJ. Time will tell. [\indent]

I'm told the clutch is OK, but I will be taking the engine out for better access and doing oil seals on the gearbox. That might be overkill but it's winter so I can work in the garage when time is available. Extracting the engine is the easiest option overall.

I might also need to replace the alternator. The one on my 100HP got noisy - cracked casing. MUCH easier with engine out.​

 

[koalar]

lets not get onto doom and gloom of timing chains. The mechanic would not be aware of the new battery

the original poster had a noisy low pressure pump
its now not making any noise

its either not getting power, inertia switch triggered
or
the motor stalled and a tap will get it going temporarily

yes there could be other reason for the pump not to be running. But if I took 100 cars where the pump isnt running there would be a Good chance that all 100 either had a stuck motor or inertia tripped. This is where I would start First

I have had the fuel pump fail on my petrol panda. Similar pump

Did drive the car home after tapping the pump to get it going again but it failed again the following cold start but again could be restarted with a tap. I did mange to move a car that had broken down in the street by bashing under the fuel tank. I pretty common not just pandas

 

[DaveMcT]

To test the pump, run a test wire from the battery to the fuel pump. You will need to remove the rear seat base and remove the pump access cover. If the pump runs and the engine starts you know it's a wiring or relay issue. If the pump runs and the engine does not start, you'll have to look further.
I have not opened either to confirm if these are viable Other's will be along to say if this is useful information -
On most engines you can see the cams via oil filler or some other means. The M-Jet however is not so helpful. Lift the air filer/intake box and you will see the cam sensor on the exhaust cam. Lifting this (one M6 bolt) may well give a view of the cam beneath. Alternatively, the breather hose fitting is at top of the cam chain cover at the inlet (rear) side. This again has one bolt and lifting that fitting might give a view of the cam.
Self evidently, if there is no movement from the cam with engine cranking you have a can drive issue. If it's turning, happy days. But if it's done around 100K miles, think seriously about changing the cam chain.