[M6RKK]

C16XE transplanted in my Corsa, which was originally a 1.0 12v. Since the conversion has been done (about a year ago), the car has been misbehaving in the most odd way.

Starting from cold, the car starts and idles fine. Take it out a blast, and it's fine. Continues to idle well, no problem. The problems start once the engine has heated up.

The first time you put the foot down and bring it above ~4000rpm, the MIL illuminates and all hell breaks loose. The car will either idle at ~2000rpm, will hunt about 300~600rpm, or will die completely. The car has stalled before with the MIL extinguished, but that's a rare occurence.

The engine performs fine and pulls well for a 1.6, so doesn't appear to be suffering from the MIL.

We've tried the 'paperclip' trick and all that's flashed up is "12 + 12" (i.e no fault found), even after the engine has been driven for hours with the MIL on. Trying to pull the code with th engine running causes the MIL to flash steadily at a rate of about 2 flashes per second.

Things that have been replaced on the engine:

Lambda sensor (two of)
MAF
ICV
Coolant temp sensor
Upper inlet manifold
Coil pack
ENTIRE engine wiring loom
ECU
Earth strap direct from engine loom to neg on battery.

The problems only appear when the engine is warm, but sometimes even when fully heated, the engine will run perfect. Will idle fine, no MIL and pulls well.

Anyone got any suggestions before I fill the bores with sand and crank it til the battery dies?


Alllllsooooo.... The engine started playing a new game tonight called 'flicker the oil pressure light at high revs'.

The oil has been checked and it's pretty much at the top of the dipstick, it only appears when you cane it. I've suggested blocked oil pickup or dodgy pump. If the PCV system is blocked, would excessive pressure cause the oil pressure light to come light on these engines?

 

[Deathscythe]

It sounds like a fault in the PCV system, if the crankcase pressure was too high, oil may be forced into the intake side of the engine, causing your rough running (which would bring the MIL light on because the engine ECU doesnt know what is going on because its sensors are reading within their tolerances but are saying that it isnt running properly, so its confused). take off each pipe in turn and clean them out before refitting them, check any filters and renew them if theyre blocked or suspect.

your oil light would only illuminate due to a critical loss of pressure, if its flickering i'd suspect that the oil relief valve in the oil pump is sticking open. the valve is on the rear of the engine on the timing belt side and might be awkward to get to, but id have a look at it and see if it is full of crud. a dealer shouldnt have a problem getting hold of one and i cant see these costing much.

 

[M6RKK]

Thanks mate... al look into this and hopfully get it sorted.

 

[Donthatemecosinomorethanu]

If the oil pressure relief valve was sticking open, would it not cause a loss of pressure throughout the rev range? At high RPM, the pressure surely shouldn't drop....?

I'm not entirely familiar with the internals of these engines, but do these valves have complicated diaphrams or just a simple spring actuated by pressure?

It was noted when the engine was fitted that the inlet for cylinder 3 contained a large amount of oily gunk, how does the PCV system route it's breathers? I might try disconnecting the PCV system and plugging the inlet, and let the PCV vent to atmos.

 

[Deathscythe]

If the oil pressure relief valve was sticking open, would it not cause a loss of pressure throughout the rev range? At high RPM, the pressure surely shouldn't drop....?

I'm not entirely familiar with the internals of these engines, but do these valves have complicated diaphrams or just a simple spring actuated by pressure?.

there are usually two types of relief valve fitted to modern engines, piston-type and ball-type. the piston type uses a sleeve drilled in certain points with a spring acting on it at one end, the sleeve can spin all it wants, but when the holes line up with oil galleries in the valve bore the oil is allowed back into the sump. the failings of this type are that the sleeve can stick at certain positions until either the spring or the oil pressure itself frees it from the valve bore and that chunks of crud can jam it solid fairly easily, it is also sensitive to foam in the oil and can cause the light to flicker when there is foamed oil in the system.
the ball-type is simply a large ball-bearing with a spring acting on one side, usually fairly reliable unless the chamber behind the ball bearing fills with crud or the ball wears unevenly and starts sticking or relieving pressure when its supposed to be closed.
both of these can usually be stripped and cleaned to eliminate these problems.
when the engine spins up, the oil pressure should rise until it stay at a certain level (that depends on the engine) and no more. petrol engines are roughly 2-3 bar oil pressure normal at max revs, diesels are a bit more, but i have seen a mondeo stv6 pull 7-8 bars oil pressure and none of the crankcase seals blew and it ran fine, so it can be a bit strange.

It was noted when the engine was fitted that the inlet for cylinder 3 contained a large amount of oily gunk, how does the PCV system route it's breathers? I might try disconnecting the PCV system and plugging the inlet, and let the PCV vent to atmos.

deliberately plugging the PCV system is a bad idea because the gas flow within the engine is used to help scavenge oil from the head and back down to the sump so the oil doesn't have time to start burning into the hot faces in the head. if you plug it or the engine breathes too easily, oil can burn into large chunks which will fill the pre-filter on the oil pump, causing oil starvation. a lot of the nasties in the gasses, like oil vapours and blow-by gasses, get recycled through the engine when the internal pressure is at a certain level and are burned before being thrown out of the exhaust. the internal gas pressure is also important for seperating heavier particles of oil mist back into fluid to be re-used in the lubrication system. one thing i have seen with people who have fitted aftermarket breather filters (like the ones you can get from halfrauds for a tenner) to every vent hose they can see is that they can start burning their own oil over time, leaving them constantly topping it up until the big-ends let go, leaving the engine a lump of scrap.

sorry if im rambling, im hyped up from drinking way too much coffee all day.

 

[GSi mark]

after reading all the threads i see nobody has mentioned the air flow meter, the reason i say this is my c16xe was acting in simular way, when it warmed up it would missfire, hunt all over the place and also stall at junction's, i had my mil light on also and when checked with paperclip test brought up throttle postion sensor and no signal at vss on ecu but the latter was due to my fitting digi dash and not linking it to ecu,

however after changing tps and icv i almost gave up and then to my horror noticed that 2 wire to the air flow meter were rock hard and when i moved the afm they snapped off so a quick re-wire and the car is running better than ever

god i do waffle eh hope this helps out

 

[corsasi]

first tiem i read this and i wana gona say possibly airflow meter, mine used to run fine on cold, and then **** about when it was warm, itll cost you about 30-50 quid to get it on diagnostics at a small garage, they can tell you if its a sensor