All started 2yrs ago when the car had an engine rebuild due to Number 1 piston and liner failing………car has never left their garage since
Mechanicaly they say the engine is fixed and the car starts up fine but once warming up, it goes to 3 cylinders and miss fires.
They’ve changed the leads, crank sensor and some other bits but it still does the same, they’re now saying that they haven’t got a clue what to do to fix it ?
It’s running the OE ECU which has never previously been a problem.
Any ideas as the car is no nearer to being returned to me
Valve clearances?
Does it still have comp on all cylingers when hot and misfiring?
What about a cylinder leakage test, has one been done??
Can only really be three things
No fuel or air
No compession
No spark
Have they tried changing the coil pack Graham? If that’s on its way out I’d expect it to show up more when it’s warm/hot. Cheap to replace (Vauxhall Cavalier part, don’t pay Lotus prices )
I thought valve clearances as i’m pretty certain that’s what caused the liner to crack in the first place, (after the previous recent rebuild)…they’re saying it’s not that but i’m not convinced.
I’ll ask them regarding your list of things on Tuesday because the mechanic has put his hand up and said he’s now run out of ideas.
How long does it run OK for and what is the reading on the water temp when it starts to run badly? Is it really running on three (which cylinder is cutting out) or is it just running really rough. I ask the questions because it makes a difference to determining what’s wrong.
Gets engine running gradually worse while warming up or is it more of a sudden change? The ECU runs in open loop while being cold and switches to closed loop mode once the engine reaches a certain temperature (closed loop: ECU tries to control mixture and ignition by looking at the current lambda readings).
Lots of things can go wrong there (bad lambda probe, air leaks, etc.). You may think of hooking up an OBD scanner to see what the ECU is doing. Check the ‘sorting VHPD drivability’ thread for more details.
That is exactly why I asked my questions. Not sure if you have this saying in Germany, “great minds think alike, and fools seldom differ”. We are thinking the same! Keith
OBD scanner, as Klaus recommends, should hopefully give you a steer with any errors that flag up. Also I’m wondering if, as the fault only occurs once the engine’s hot, whether heat is affecting a wire ( eg. injector cable ) causing a bad connection or a break to open up?
I’ve been told once it gets to temperature, it drops down to 3 cylinders, misfires and runs like a bag of spanners…i’ve not witnessed it running but they say it’s also running very lumpy compared to usual………that’s basically all that I know plus they’ve replaced some parts that haven’t made any difference…….i’m thinking liner heights ?
The same company did the first rebuild which lasted 2wks and it was cyclinder 1 that failed (liner cracked) piston 1 was also replaced for the second rebuild.
So it’s lumpy all the time and as it gets warm it gets worse? When they say running on three the just mean it is lumpy and is missing some firings. Does it back fire and make bangs out if the exhaust? Is that a better description, I know it’s hard to say as you are going on what they have said to you. Very different problem if it’s always rough and gets worse.
Keith, I don’t think we have that saying in Germany in full length, only half of it: ‘Zwei Trottel - ein Gedanke’.
Unfortunately it corresponds to the second part of the English saying.
They say from start up to temperature, it runs fine…once at temperature, it drops to 3 cylinders, misfires out of the exhaust was their description and it won’t pick up revs.
I’m hoping to pop down this week tofind out for myself.
)
