Ideas on a bad miss...

[LINKIN]

I have 3.0l Pajero, had a miss and needed a top up of water once a week, Did the heads up, did timing belt, plugs, leads, cap and rotor. still has the exact same miss, compression ave of bout 165 per pot. auto elec cant find any elec problems. the miss is constant from idle right through to high range, is this likely to be an injector problem?
Thanks

[DamTriton]

Did you just tighten up the heads or replace the gasket? Sounds a bit like a cyl-waterjacket breach of the head gasket if it is using water, especially if it only when it is running. Does it leak water when left standing after a run?

Try sprinkling talcum powder around the head gasket area (makes the water easier to spot) and leave newspaper under the vehicle to catch drops.

[LINKIN]

Had the whole lot apart, heads got recoed, not using any water/coolant at all, oil is clean, not blowing any smoke, compression is good.

[DamTriton]

Blocked injector could do this, especially if it is sequential multipoint.

I've got a Kia that's doing that at this moment after a bad load of fuel.

Have you tried shorting out each spark plug to work out which cyl has the problem (it will be the one that doesn't make the problem worse), then swapping the position of the injectors to see if the problem moves with the injector. That would be the definitive way of sussing out if the injector is OK.

Further out from that try a new ECU if you can swap with a mate for testing purposes, it could be the injector output stage of the ECU that is having issues.

[ludacris]

The ecu,s do fail at times but if the auto elec checked it then he should have picked it up. It could be a faulty spark plug. Not enough fuel pressure. Or injector. Go through the spark plugs and unplug them one at a time while the engine is running then go through the injectors and un plug one at a time while it is running.

Cris

[DamTriton]

The ecu,s do fail at times but if the auto elec checked it then he should have picked it up. It could be a faulty spark plug. Not enough fuel pressure. Or injector. Go through the spark plugs and unplug them one at a time while the engine is running then go through the injectors and un plug one at a time while it is running.

Cris

...Did the heads up, did timing belt, plugs, leads, cap and rotor....

He's eliminated the spark system.

Low fuel pressure would not produce a regular miss through the rev range.

[lucifer48]

Clamp the fuel return line at the fuel rail and see if the miss goes away.
If it does (or improves it a little) the injectors would need cleaning.

Might want to pull them out and get them cleaned anyway.
Also did you change the seals where the injector goes in the manifold?
It could be leaking air through there.

[date]

Have you tried using the engine check light function? You have to short out Pin No 1 of the diagnostic plug to earth and then turn on the ignition. The Check Engine light will flash long ( a couple of seconds) and short (half a second) flashes. This gives you a code eg 2 long and 5 short flashes is Code 25. The w'shop manual will then tell you what the code is and you can chase it down. I haven't used this system, but have been told that it works.

Despite having the ignition system checked, I would still suspect this - it may be a lead shorting to earth somewhere. Have you tried lifting the bonnet in total darkness. You would be amazed at how many leaks to earth you can see in a lousy ignition system.

[LINKIN]

Thanks for the advice guys, injectors are out and fetting cleaned in an hour or so.. I have had the bonnet up in the dark, couldn't find a stray spark anywhere, and i did replace the seals for the injectors into manifold as these came with the VRS set.
Will Tonka later this arvy with wether or not the problem has been sorted.
Benny

[LINKIN]

Injectors was definantly a problem, 1 was running at about 5% and the other 5 were all good and cleaned up first wash, the injector in question took 6 washes and is still only bout 90%, i put them back in anyway and will organise a reco set sometime soon. Quoted $198 to do all six, but when the guy got here it is $150 without an invoice.

[lucifer48]

If you were down in Sydney i would do them for $90.00 with new seals and an invoice!!