So I serviced my mother's 1.4 8v MPi (without issue) and then I proceeded to order and fit the same spark plugs for my own 1.2 12v which didnt appear to be a problem until I tried reversing the car off the drive

It started and ran but after moving a few metres the engine just died out (no awful noise) and hasnt started since

 

Obviously I quickly realised the spark plugs weren't correct (shorter than necessary and with multiple electrodes) but Ive fitted the correct ones, as well as replaced the ignition coils, with no luck

 

It appears to be difficult to test the ignition system as a whole on this engine to see if there is a spark but I may be missing something

 

This has been giving me a real headache for a few weeks now so if anybody has any suggestions of things to check they would be greatly appreciated

I should also add dont assume that Ive checked something that you might deem obvious because Ive not got a lot of experience

Ive had the car for just over a year but Im only 18 myself

Check fuse 52, which supplies the ignition coils.

Ive tested fuses 52, 61 and 14, they are all fine

I also ruled out anything fuel related up to the injectors themselves after being sent down a long rabbit hole by a family friend

Do you have a compression tester, or know someone you could borrow one from?

Are you sure your getting a spark. Connect a timing light or similar to check. I have one of these

 in line spark checker.

Might be that you pulled the main HT lead  when changing plugs or distributor problem?

Alasdair

Ive got no idea if Im getting a spark and I have neither a compression tester nor an in line spark checker but I can borrow one from a friend

 

Just out of curiosity what is a minimum healthy voltage reading when cranking?

The only other part I messed with knowingly was taking the battery out to charge it (which Ive had to do numerous times now)

If its cranking then the first I would check was if your getting a spark, Next fuel before doing anything else. If it was running well before then its most likely something that you have missed or disconnected/dislodged. Check the strip fuses at the battery and wiring. 

Alasdair

7 hours ago, Possum114251 said:

Ive got no idea if Im getting a spark and I have neither a compression tester nor an in line spark checker but I can borrow one from a friend

 

Just out of curiosity what is a minimum healthy voltage reading when cranking?

The only other part I messed with knowingly was taking the battery out to charge it (which Ive had to do numerous times now)

Not sure on the votage when cranking engine. I have in the back of my mind about 9.5-10 volts. Anything less would point to a failing battery or one thats needing charged but if it cranks over at a normal speed then I would assume theres enough for creating spark etc. 

On 22/12/2024 at 18:34, Breezy_Pete said:

Do you have a compression tester, or know someone you could borrow one from?

I bought a cheap one off amazon. It was only £15-00 . Not sure how accurate it is but it shows if compression is low or if one cylindesr is a lot lower than the others. I got it to check a very old LPG forrklift and luckily it showed all cylinders were about the same and reasonable. Turned out it was the distributor . I got this one but in an orange box, For £15-00 even if you use it once then I reckon its paid for its self plus its a handy tool to have.

https://www.amazon.co.uk/gp/product/B07RTY7Q1R/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1

Yeah, you don't need to spend much to get something that's perfectly adequate. 

Unfortunately the HTP engines are vulnerable to chain jumping, the tensioner having no ratchet mechanism. 

Compression test may be the easiest demonstration that something is badly wrong.

 

 

 

 

15 hours ago, Breezy_Pete said:

Yeah, you don't need to spend much to get something that's perfectly adequate. 

Unfortunately the HTP engines are vulnerable to chain jumping, the tensioner having no ratchet mechanism. 

Compression test may be the easiest demonstration that something is badly wrong.

 

 

 

 

Yeah Ive been attempting to eliminate everything else before biting the bullet and accepting its the timing chain

 

It seems the battery may be on its way out as well as it drops to 9.2V and the negative lead is a bit loose also but sadly I dont think those would stop it sparking since it still turns over

 

Ill find spark and compression testers one way or another (likely after Christmas) and then see what they tell me

Oh I just remembered that when I crank the engine for probably a bit longer than necessary I get a beep and a red oil pressure light

 

Is this indicative of anything or just something to be expected when cranking for too long?

9 minutes ago, Possum114251 said:

Oh I just remembered that when I crank the engine for probably a bit longer than necessary I get a beep and a red oil pressure light

 

Is this indicative of anything or just something to be expected when cranking for too long?

That's normal in those circumstances. 

45 minutes ago, Possum114251 said:

Oh I just remembered that when I crank the engine for probably a bit longer than necessary I get a beep and a red oil pressure light

 

Is this indicative of anything or just something to be expected when cranking for too long?

I get that on my diesels when I have changed fuel filter. It takes a while to get the fuel back through hence the beep and oil pressure light until it starts. Did you change the fuel filter when servicing it? Just wondering if its an airlock or perhaps fuel pump problem or if the filter is choked. You could pull a spark plug out after cranking to see if its wet with fuel.

Alasdair

23 minutes ago, Alasdair1 said:

I get that on my diesels when I have changed fuel filter. It takes a while to get the fuel back through hence the beep and oil pressure light until it starts. Did you change the fuel filter when servicing it? Just wondering if its an airlock or perhaps fuel pump problem or if the filter is choked. You could pull a spark plug out after cranking to see if its wet with fuel.

Alasdair

No I was only changing the plugs on mine and it had ran pretty great (albeit a little rough) up to mid November when this happened

 

Really I shouldnt have messed with it but I have no recent service history and I still hadnt changed them since buying it and sorting it out

 

Hindsight is 20/20 though

It won't be a fuel filter problem. 

 

All three cylinders are getting a spark

In line spark tester wouldnt fit (1.2

things I guess) but I took each plug out and reconnected it to the coil and cranked it from there

 

Attempted to run with easy start but all that would do is make it pop a bit

 

Havent had a chance to compression test as battery died again so that will be done tomorrow

 

Upshot is, battery is a problem but likely not THE problem

I would perhaps try another battery or if you dont want to buy one then jump start?  The 1.2 doesnt need much to turn it over at all but the electrics may struggle if the voltage drops too much especially when cranking. The starter will take most of the power and cause a further drop in voltage If your getting a spark it may be that  the coils work at a lower voltage. Other electrical parts like relays,injectors etc may need more. You mentioned 9.2 volts which is pretty low. It would crank engine at 9.2v but electronics etc are probably looking for10v-12v min. My Octavia diesel dash is like a christmas tree when trying to start with a low battery. Hope its just the battery and you get it sorted. 

Do the compression test ASAP please, all this speculation is pointless.

On 30/12/2024 at 19:26, sepulchrave said:

Do the compression test ASAP please, all this speculation is pointless.

Yeah its currently -4 degrees where I am I appreciate its taking some time but nobody is more irritated about it than I am

 

I also have a new battery which Im yet to fit as well due to the weather

Alright so compression test is done

Result was an even 12.5 bar across all three cylinders

 

Also got 0 fault codes (other than radio antenna and A/C) on a proper dealership piece of kit

Should add, currently fishing for the crankshaft position sensor with limited success

I replaced the cam and crankshaft position sensors which sadly achieved nothing

 

Ive confirmed that all 3 cylinders are getting fuel, healthy spark and decent compression which Im fairly certain does leave me with the result of a jumped timing chain

 

Assuming that its only a minor jump and nothing is noticably damaged could I get away with only replacing the tensioner?

Ive seen posts saying the sump would have to come off to replace the whole shabang and since I currently cant get under the car that would be rather difficult

Any advice on tackling this would be greatly appreciated I have 3 weeks of mock exams and then a week off which is when I plan on giving it a go

 

I guess if its any consolation the new battery meant the offside rear door now unlocks when it didnt before... hooray.

Remove the two covers from the gearbox end of the cam cover which give you access to where the cam locking tools fit.

You will be able to see the slots in each cam that the tools fit into.  They should be always parallel to one another; and when cylinder 1 is at top dead centre, they should be parallel to the head gasket. If either of those conditions is untrue, the chain has jumped.

 

Here's a pic of ours when newly acquired, with some flat bits of alloy stuck into the slots to investigate parallelism (at TDC).  

 

Changing tensioner alone is not possible without almost all the same work that would be involved in changing the whole timing kit, it lives under the one-piece alloy cover at that end of the engine.

There are horizontal locating dowels in the engine block that mean the cover has to be removed horizontally after all the fasteners are removed. It will probably break if attempts are made to remove it in other directions.

 

Tensioner visible here with timing cover removed (in 2020), just below water pump. And locating dowels can be seen in the block too.

 

 

Since the cover is attached by sealant as well as about 30 fasteners, to camcover, head, block and sump, it is difficult to remove even with the sump off, let alone without, where the sealant to sump would have to be broken in shear. Would be nigh-on impossible to refit the cover to the sump (with sump left on) oil-tight using sealant unless the dowels were removed and omitted. The image shows the sump loosely refitted after the timing cover was removed.