Thanks guys for all the support, I'm just recharging the battery now until tomorrow. I'll try out the few things you have suggested, at which point I might get a mechanic to come and look at it. Because it was running fine (when it would start) I'm thinking there's something at play which I'm not clever enough to noodle out.

Sorry for the delay, had a fraught few days.

The Haynes for the Cinquecento is not that helpful. I've scanned the wiring diagram, but it helpfully fails to show how the ignition switch tells it all to work.

I think it still comes down to checking each component and ensuring the electricity flows when it should.

If fuel is being injected, pump and injector are working, and crank sensor is sending a signal. Problem should therefore be sparks, or timing. Have you checked the cam timing?

If spark appears ok, and cam timing ok, do a compression test, might be head gasket.

Thanks Bill, I've had a few days away from it too.. I did find one of the coil packs was bad, replaced it but still a no start.

I went down to my local garage and he suggested it could be the CPS, I've got one on order should be in next week, now to figure out how to replace it!

Fuel to throttle body is good, inlet manifold is clean, Spark is good now x4. I tried to get the timing covers off today but needed a bigger socket for the alternator tensioner. Picked up a new socket set on gumtree for 5 bones!

But I have night shifts coming up this weekend so I've got to leave it until tomorrow to check the timing.. I've read on another thread that it's pretty straightforward on these engines... non interference is a nice safety net too!

I don't think it's compression, simply because when it was running, it would idle fine, drive fine etc..

If it is a head gasket, I'd be putting some steel seal in it, failing that I'd probably have to sell it.

Hi again, so I've ordered another CPS, starting to play the 'replace everything' game. Ive tested the old one and it is producing a voltage when I pass a spanner by it. I checked the reference voltage with the key on and it's at 2.5 volts. I was expecting a 5 volt reference, which makes me think something's up with the wiring.. it's a Bosch cps, it's not budging when I try to remove it and I don't want to wreck it if the new one is the wrong one... does anyone know the correct reference voltage?

Also the drive pulley was a bit rusty, is there a chance the corrosion could interfere with the sensor and mess up the timing?

If your getting spark and fuel then the ecu and its sensors are working fine (at least for a start and rough run). This means that the most likely culprit will be the timing. Have you checked the timing belt is fitted correctly against its timing marks, as little as one tooth out can sometimes stop these engines running. Check the belt tension first, if this is slack it can easily jump a tooth or two.

Hmm.. yes I think they're lined up, I pulled the cover off today.. belt seems to be in tact but there were a couple of pieces of ?old belt jammed in the crank pulley. I reckon I might change both belts anyway. Tension is fine.

The thing is it was starting, and when it did it ran absolutely fine. Now it's just not starting at all. Any thoughts on the 2.5v constant power to the sensor?

Ah it could be from the side of the belt which has pulled the belt around a notch or two

If it was running fine previously, you need to look at what has happened between it running and it not. Work through everything that has been done in that time and verify that it is correct. Randomly changing parts in the hope it will fix things will only cause frustration and an empty wallet!

That's just it. Aside from changing the coil out the other day, all I've really been doing is fiddling around cleaning terminals and wiggling things. Anyway it'll be a while before I can get back to it but I'll post an update if/when I can get it going...

Okay so here's an update for ya. I've now replaced the timing belt and drive belt because they were looking old, and cheap. And this is what I found.. stripped around the crankshaft pulley. Additionally I can't turn the cam pulley by hand. I was worried about shearing the bolt head so I chickened out after a bit of pulling. With the new belt installed it turns the cam over though.

I'm in uncharted territory here and because I'm mucking around in my own I can't watch the engine while it's turning. I'd like to see what's happening under the cam cover when it's turning. I took the camshaft out and neither it or the followers had any wear. Are the followers meant to stay stationary or pop up? I'm worried the valves could be stuck...

crumbtoasty said:

Okay so here's an update for ya. I've now replaced the timing belt and drive belt because they were looking old, and cheap. And this is what I found.. stripped around the crankshaft pulley. Additionally I can't turn the cam pulley by hand. I was worried about shearing the bolt head so I chickened out after a bit of pulling. With the new belt installed it turns the cam over though.

I'm in uncharted territory here and because I'm mucking around in my own I can't watch the engine while it's turning. I'd like to see what's happening under the cam cover when it's turning. I took the camshaft out and neither it or the followers had any wear. Are the followers meant to stay stationary or pop up? I'm worried the valves could be stuck...

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The force needed to open a valve against its spring will be more than you can create trying to turn the cam by hand. So that isn't an issue.

However, the belt teeth stripped suggests that something stopped the cambelt turning. That'll be either the camshaft, or the water pump.
You've had the cam out and it looks OK, so I'm assuming its bearing surfaces are good, which suggests the cam had not seized, at any time.
With the cam out, all the followers should be about the same height, as all valves should be shut. This is a 'safe' engine, so pistons and valves don't meet. With the cam in place, and no belt, you should be able to turn the cam with a spanner and open all valves in turn.

My guess is the water pump may have seized. Don't discount this because it will turn now. It may have seized and then let go now. Cheap and easy to replace, so just do it.
Also check the cam tensioner. Did a new one come with the belt? This would not stop the belt turning, but would burn the back of the belt, but always worth changing with a new belt.

Thanks bill.. this was my worry, I was trying to turn the cam with my ratchet and it wouldn't budge... The bearing surfaces had some crud on the inside but nothing major... the water pump is only a year old so I don't think it's that... I'll have a look again soon... how much force should it take to depress the cam follower? I feel like if I lean on it it should at least move a little bit no?

Just leaning on the follower is unlikely to move it. With the cam in place, you shouuld be able to lever against the cam to push the follower down. But be careful, don't lever against the cam lobe, only the rough cast part of the shaft, and ensure whatever you use does no damage.

Out of interest did the camshaft area look nice and oily when you took the cover off? Could be the spray bar along the front blocked if oil changes have been skimped on in the past leaving the camshaft running dry which will stiffen it up pretty quickly. Shouldn't really be "crud" around the cam bearings, just oil. If you've got the spray bar off along with the camshaft try and spray through with an oilcan or WD40 to see if oil comes through all the holes.

Hi, yeah it kinda looked like oil burned onto the metal, not like dirt, but looked like stuff that gets burned onto a frying pan if you know what I mean? Cleaned it off with a bit of WD40 and a cotton rag, took a bit of scrubbing...

I did get the spray bar off and blew through it and tried to block the holes... I'm pretty sure they're good but wouldn't hurt to give it a spray.. the camshaft was definitely oily when I opened it too �� I might go try fitting a new crank sensor soon.. on night shifts so I only get like an hour to do anything during the day before I have to go back to bed

Check there is actually oil coming up through the head. There have been instances of a head gasket fitted upside down, so the oilway is blocked. A camshaft can last a long time just on the oil it got when topped up, or last changed, as it gets a bath at that time.

Once saw a Rover V8 engine with no oilway in the head. Rocker gear only lubricated by oil from initial fill, changes and top ups. Lasted 85,000 miles before it got noisy. Only rocker gear, no camshaft, but illustrates the point.

Heya

So I replaced the crank sensor, timing belt and drive belt, which produced the first 'start' for quite a while. It ran for about ten seconds and sounded like only two cylinders were firing 'sigh'...

Tappet cover off revealed that one of the valves was stuck open, removed the timing belt and turned the camshaft with my socket wrench (it turns now) which caused a further two valves to stay down. Camshaft now out, and after playing around a bit I've found that the other valves are working fine. So both valves on Cylinder 1, and the exhaust valve on Cylinder 2.

Currently have a magnet on order to get the tappets out, then I'll try to run some penetrating oil down there, get them freed up, run some de-gunking additive around for a bit and then change the oil out.

Probably easier said than done, but the 'almost start' has given me a new enthusiasm

Good work.
I'm guessing it has stood around for a while before you bought it. The sticking valves will be the ones open to the atmosphere while it was stood, so have a bit of rust on their stems.

portland_bill said:

Good work.
I'm guessing it has stood around for a while before you bought it. The sticking valves will be the ones open to the atmosphere while it was stood, so have a bit of rust on their stems.

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Brilliant don't give up now you have anew set of skills sj