Topic

we have tested all aspects of the ignition system. new spark plugs, new leads and new coils

I too am out of ideas, if the OBD shows no problems. I strongly advise you to call MGrover solutions rather than throwing more money at it. Russell is not easy to get hold of but persevere. He is very knowledgeable about these cars. Mention the T Bar and that I recommended him.

He is always ready to offer good advice and may have come across similar problems before. He may be able to fit you in and has all the proper kit T4 etc.

Have you checked the voltage at the coils?

Do you know for sure there is a spark?

Had the same problem with my ZR, though mine was caused by a fault in the LPG switchover system (caught fire, long story but car ok and back on road)

To rule out an ECU related issue, get a known working ECU and plug it in, turn the car over and if all is well it should fire briefly before stopping. If it does this your old ECU is fried (new ECU needed plus T4 or security ECU), if it doesn't, check wiring from coil to ECU, just to eliminate

Have you done fuel pressure tests?
A cause of excessively high fuel pressure, could be a buggered fuel pressure regulator valve or a blocked return line.

Right - found the problem!

We have low compression on all 4 cylinders! about 40psi!

what could that indicate? Timing seems ok?

OK, even if your timing is good, it could still be that your valves are stuck open.
The hydraulic tappets could be over pumped, holding the valves open. this could be caused by various reasons like poor maintenance, wrong oil grade, damaged pressure relief valve in the oil pump etc.
You need to do a cylinder pressure leakdown test to determine where your compression is being lost.

Ok, will try and get that arranged.

I have a funny feeling that it has been overfueling for a while now. I found that the ECU thought the throttle was 100% open all the time, due to a faulty TPS

The car starts first turn of the key with a tiny bit of oil in the cylinders. As that oil burns away, the car splutters and dies

Im thinking the worst!

Putting oil in the cylinders will increase the compression, particularly if the piston rings are bad.
You really do need to do a leakdown test to determine where you're loosing compression.

I find all this trans global diagnosis a bit frustrating, if all you lot lived here in Melbourne I'd be able to sort most of your problems pretty quickly as I have just about every tool and diagnostic instrument you could need stashed away in the shed.

I can understand your fustration! Me and my GF are both students, and this sort of repair can run into hundreds and hundreds just for dianostics!

Thanks for all your help! We should have a tester here shortly

As Cobber has alluded to, the old Skool, and presumably current Skool test is to whip the plugs out and squirt oil or Redex down the plug 'oles. Crank the engine over and test the compression pressure: if it improves the chances are bores/rings etc are nadgered. The oil gives a temporary seal.

If no change, it's valve related.

Potential bad news: if the valves haven't been fully closing for a while then even if you find and rectify the prob, the seats will probably be damaged and leak through.

40psi is a tad tragic......

Hi,

Got a pressure test done on the engine. They said it was most likely bored wash.

Done the oil trick and starts first time with about 140psi pressure.

Not sure if the bore was will go away after being soaked in oil for awhile?

If not sounds expensive!

Thanks all for your help

Progress at last - replacement engines aren't much now, cheaper than repairing in many cases.