Been working on a vauxhall

Pity me

Been here before and swore I would avoid touching this shod, I wish I had said no.

Anyhow, here's the crack:-

Corsa B - think its a 1.6, its a twin cam 16 valve jobbie. It runs, but miss fires. It's been to 3 or 4 different garages and has had about £2000 spent trying to fix it (at these other garages) including the following:-

new cam shafts
lifters
full head rebuild and skim
new piston rings(???) and a rebore according to the receipt but I think its a lie
new plugs
an "ecu reprogramming" (again sure its a lie)

So it's turned up in lap for one reason or another, a friend of a friend and all that crap

What I've concluded so far:-

Error code on the ecu - "misfire detected on cylinder 4"
The coil pack is fully functional
All the injectors are working except number 4 doesn't work, but if you swap them around number 4 still doesn't work
The crank sensor and camshaft position sensor work perfectly as i've had an oscilloscope on them
Throttle position sensor and MAF work perfectly
When you first start it up injector number 4 does work, but after 30 seconds it stops firing
I'm starting to hate it

So next step I'm not sure, but i'll sleep on it and maybe an idea will turn up from somewhere. I'm thinking the injector driver circuitry in the ecu might be burnt out, but I've had that open and it looks ok by eye. Ideas?

p.s. I may hate it but I love a good problem me! I'll solve it sooner or later.

I had a corsa once, it worked lovely, till some bint pulled out on me crossing a dual carigeway and I crashed head on into her
Can't offer any help on your problem tho! I'd make a wild guess and say a dodgy wire!

Is it common rail or distributed fuel? can you hook up a visuale display like a bulb off the injector wiring to see if it is getting a signal then you can look at the lecys or the fuel supply.

If the 4th injector does not work after a short period running, but phisically the injector works properly if connected in another position, probabily the problem is in the wires, or in the ECU.
If it is the injector that has the problem, not depending on his connection to the ecu, probabily the defect is in his coil, or (less probably) in the injector there are some iron debris that modify the magnetic field, causes the coil to have a higher current draw.
The injector driver in the ECU maybe have a sort of overload protection, then it stops driving the injector after a short time.

If you disconnect the injector before starting the engine, signal still arrive to the connector, or it stops not depending to the injector connection?

Common rail jobbie. My oscillorscope says the signal just fades away to nothing - so your idea of a bulb test rich is bang on but i'm already on it

Its not the actual injector at fault as i've swapped them round.

Pretty confident now that its the injector driving circuitry, probably a transistor or something that's nailed.

Really I could do with fixing the ecu as if I swap it i'll have to do something about all the keys as they are programmed to the immobiliser with the ecu and I don't yet have an op-com lead and cracked software setup.

I just hate working on vauxshite, all the connectors are crap and the sensors are in stupid places, and that bastard big multi-coil pack is a pain to test out. It's like everything on the car has been designed to make the car disposable.

Pauxhauls are disposable and most of the drivers should go with them.

I'll drink to that - along with poogeots, shitons, f(i)arts, arse hole audis, beemer heads, veedubbers and bloody fords!!!

Fords are good but only the old ones thats the 80's and earlier as the parts are super interchangeable. by that list why don't you get a TATA?

DFSK isn't on there either though, but am I retarded enough to buy a load hopper?? Not that you can find any reviews of the minivan microvan

Hey back to this fecking corsa!

It's still sat in my garden, so over the last few days I've been fault finding it like a detective. So far I have found lots of parts that definitely work fine!

All the injectors are cool, the spark system works perfectly, the compression is sweet, the cam timing etc is sweet, the coil pack is sweet, the inlet side is all perfect, the maf sensor is good, the throttle control solenoid and TPS work sweet. The ECU fuel side wiring is sweet.....

I'm pretty sure tomorrow morning I will find the fault on it as I have a really good idea of what is the possible causes and what are the symptoms!

For those sad buggers who like this sort of thing I've been writing a diary of the diagnostics which I will post up a link to as soon as I've beaten this bloody vauxshite.

Found the fault!!!!

Only took about 30 hours detective work

Turns out, the inner plastic cage of the oil filter has broken, this fragmented plastic has gone right through the oil system including the cylinder head.

There is a blocked oil way which feed the hydraulic tappets on cylinder number 4, so they are not fully charged with oil, thus the valves are not opening properly on that cylinder.

I took the sump and oil pickup off it, to find loads of plastic in there, which combined with sump gloop it has pretty much entirely blocked the oil pickup. So I cleaned all that out, then cleaned out all the oil filter housing, put it back together and filled with fresh oil.

Car started and ran much better, it ran for about 10 minutes until it gave me the misfire error code again - a vast improvement on the 30 seconds it took previously. The tapping noise from the valve train went away too.

So I pulled all the cams out, removed all the hydraulic tappets and emptied them out, then put compressed air through the oil ways in the head.

Put it all back together and it runs sweet now.

Saga over. Now its time to break it for bits to sell on ebay

Couple of diagnostic videos:-

See - that's what a holiday does for you, you've come back firing (ahem) on all cylinders. Did you have a good time, btw?

Good job!

The damn misfiring is back!

Not given up on this feckin corsa - wish I bloody had mind you.

I just can't sell it unless it's right, i'm too honest for my own stupidity!

So I took the head off, and all the timing chain gear.

Had the valves done, and put it back together today.

Dropping the oil out of it for the third time (how much have I spend on this POS) - I realise the oil is full of bottom end bearing glitter.

So I ran it again, runs pretty damn sweet, but that misfire code came back.

Thinking about the bottom end - I disconnect the knock sensor.

Misfire code disappears!!!!

I can only assume there is play in the big end bearing on cylinder number 4 - thats where I think the glitter is coming from. The knock sensor can hear the rattle from the big end bearing.

So tomorrow after I fix a lads fiesta, I'm taking the sump off for the 2nd time, and splitting the big end ends to inspect. But I'm pretty confident what I'm going to find.

For goodness sake Matt. Aren't you insured TPF&T or fully Comp ?