Hi all, im looking for some help as I am on the verge of a war with my fiat 500 1.2 sport 2008.

So let's start at the start. I rescued this beautiful neglected fiat 500. He had travelled 81k he had no fluids in him at all, no brakes and the inside looked like a skip and there was no key with him But looking past all this I fell in love, it was a risk but he had soo much potential.

After refluiding, a deep clean inside and out. He started to shine and the love began to grow, along came the key doctor but he would not start he broke my heart after a friend gave him a little rock he began to show signs of life and started to turn over. After a couple of turns he blew his dipstick up in the air and popped a flame out of top rear of his engine.

At this point I had committed myself to him too much than I should have, so I purchased a second hand engine on 57k miles with identical engine codes.

Full engine including all brackets, all sensors, oil control valve, ignition system, fuel injection system, inlet manifold, water pipework, thermostat, MAF, air conditioning pump, alternator, oil cap, oil dipstick, wiring loom, clutch and flywheel were included

Excluded were the*airbox, filter, ECU, exhaust manifold, air conditioning pipes, engine and gearbox mounts, gearbox, starter motor, radiator pack and battery.

The mechanics fitted the new engine and whilst it was out I had a new clutch, flywheel, cambelt and waterpump fitted and a service completed. However this was not the end of a terrible story, as there is still an eml enlightened and the RPM display is unresponsive.

The enlightened eml displayed P0335 so the mechanic changed the Crankshaft position sensor and this did not fix the issue. The other symptoms is the car does take a few ticks before he turns over and once driving there is no response from rpm display, he pulls away fine until you get to around 17mph for the next 10mph he kicks in superslow mode no matter how flat you have the acceleration likewise if you build up the accelerators pressure gradually it makes no difference. That said if you pop him into 3rd gear and drop back into second he gets a burst of energy third gear or 25+ mph and there's no issue.

The mechanic has told.me.he doesn't.know what the issue is and returned the car with a lovely bill for the work that has been completed.

Please help me to rescue me and rescue my lovely fiat 500.

Thanks Sadè

I would have changed only the engine block with cylinderhead and kept the rest (all sensors, wiring harness, ECU, throttle, manifold, ....) from the old engine. And even there are versions with camphaser and some without. So it´s tricky.

The ECU has not been changed its the original one. There had been a fire and some parts of the old wiring harness had melted so it had to be changed. Is there any way of telling if mine has a camphaser?

Many thanks

So "....this beautiful neglected fiat 500" had a fire???




Camphaser is this part:



https://www.riparando.it/tutorial/training/variatore-di-fase-fiat-500/2012/03/

Engines without the camphaser don´t have, but they have a sensor at the location in the orange circle:

We purchased it as a non runner, it wasn't due to us it was in that state. Yes when we tried to start it a flame came out of the engine. It melted several parts hence the reason a new engine was purchased.

Thank you for your help ?

Makes me feel much better about all the problems I’ve had on my cars. I dread to think what this has cost you. Care to share?

For the engine and engine swap plus clutch kit, cambelt and waterpump was plus a few other bits its cost £700

This is my engine, looks like urlt does have the camphaser, could that be the issue?

Many thanks ?

Sade85 said:

For the engine and engine swap plus clutch kit, cambelt and waterpump was plus a few other bits its cost £700

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That's not a bad price, provided you get it to run properly now.

Gina500 said:

That's not a bad price, provided you get it to run properly now.

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Yeah not too bad at all really, the mechanic thinks its a wiring fault, auto electrician coming out on Monday to fault find so fingers crossed.

Just a thought you're absolutely sure the cam belt is properly lined up?

I think your auto electrician will be able to sort it.

The only things that are common between your old engine and the new one are; a) the wiring to the cam sensor and b) the Body Control Module that's listening out for (and reporting the lack of) a signal from the cam sensor.

I presume the signal plate on the camshaft is not the same one (each engine had its own).. but if you used the same item, that could be a contender too.


The wiring/BCM fault probably caused the original non-running issue. If it was cranked over multiple times with it not firing, your beast probably suffered a build up of petrol in the inlet manifold, which is what the back-fire was. If you scrape off the burnt plastic wreckage, the rest of the engine is probably still viable.

A BCM fault is more tricky than a poor wiring connection from the sensor since that will need a replacement or repair. Replacement is slightly complicated because the immobilisor has some components on the BCM, so these need swapping over or re-programming. There are places that repair faulty ECUs though, and they can also fix BCMs too, so fixing your old one is arguably the better option than replacing it, if it's faulty.

The rev-counter is probably un-related to the whole problem. If I recall they get a signal from the gearbox rather than the camshaft. The sender or wiring may be knackered or the rev counter itself may be faulty... but again the auto electrician will be able to pinpoint what's not doing its thing.

Good job so far, to keep on it..

Ralf S.

John202020 said:

Just a thought you're absolutely sure the cam belt is properly lined up?

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Yes its had a brand new one and been checked twice. Definitely as it should be. The fault code does say crankshaft position sensor A circuit malfunction so my guess it is a wiring fault somewhere??

Ralf S. said:

I think your auto electrician will be able to sort it.

The only things that are common between your old engine and the new one are; a) the wiring to the cam sensor and b) the Body Control Module that's listening out for (and reporting the lack of) a signal from the cam sensor.

I presume the signal plate on the camshaft is not the same one (each engine had its own).. but if you used the same item, that could be a contender too.


The wiring/BCM fault probably caused the original non-running issue. If it was cranked over multiple times with it not firing, your beast probably suffered a build up of petrol in the inlet manifold, which is what the back-fire was. If you scrape off the burnt plastic wreckage, the rest of the engine is probably still viable.

A BCM fault is more tricky than a poor wiring connection from the sensor since that will need a replacement or repair. Replacement is slightly complicated because the immobilisor has some components on the BCM, so these need swapping over or re-programming. There are places that repair faulty ECUs though, and they can also fix BCMs too, so fixing your old one is arguably the better option than replacing it, if it's faulty.

The rev-counter is probably un-related to the whole problem. If I recall they get a signal from the gearbox rather than the camshaft. The sender or wiring may be knackered or the rev counter itself may be faulty... but again the auto electrician will be able to pinpoint what's not doing its thing.

Good job so far, to keep on it..

Ralf S.

Click to expand...

Thank you for your reply, im not sure on the signal plate if its the original or from the new engine? I presume its the one that came with the new engine?

I did read somewhere about the rev counter being linked to something in the gearbox that can be damaged during a clutch replacement, its just had a new clutch fitted so this is a possibility.

The auto electrician is charging £50 to come out and find the fault so fingers crossed its something simple.

I have found a place that can sort the ECU if it is that (im hoping not)

The new engine came with a full wiring loom, there were no faults when that engine was in the original car! Maybe something has been damaged during the engine swap?

Garage have said its not down to them to fix the issue, we think different they have been paid to put the engine in and get it running and that hasn't been done. If it is down to something they have done then I will be giving them the auto electricians bill ?

Thanks again

Sade ?