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[marinis69]

It apears that the engine started to run only on 4 cilinders. Doing 10mpg and has no power at all. Very shaky. I have changed coil pack, leads, and spark plugs but nothing got better. Have send ECU to check coz havent got a clues what else might be. EGR works fine. Engine diagnostic didn't come up with any codes. Just dont know what to do. Any ideas???
THAnks

[TheBoy]

If paperclip test comes back blank, its normally HT related,  Check exhaust for blocking as well.

[Entwood]

Check plug wells for oil, and the DIS pack at the back for "dryness".

The v6 uses a "wasted spark" system so that HT goes to 2 plugs at the same time, even though only one needs it, thus any HT breakdown tends to affect 2 cylinders at the same time.

Cam cover gasket leaks can fill the plug wells with oil and cause shorting, water leaks fromt he HBV or the scuttle can get to the DIS pack and also cause shorting.

The EML light will not detect HT problems as it does not monitor the HT side.

[marinis69]

Exhaust is fine. Have removed both cats and its still the same. No oil leak on plugs at all. No water leaks as well. Where does the coil pack gets the signal from

[TheBoy]

Exhaust is fine. Have removed both cats and its still the same. No oil leak on plugs at all. No water leaks as well. Where does the coil pack gets the signal from

Direct from ECU

[marinis69]

so it might be ecu fault.

[caolan_p]

i have the same prob with mine and i got 2 new disc packs they were both faulty so they are getting me an upgrade on wed so il hope it works  

[Marks DTM Calib]

I trust that when you fitted the new DIS pack you paid close attention to the lead connectiosn for the 2-4-6 bank as thye do not connect in a logical order.......

[marinis69]

I dont know actualy It wasn't me who fitted it. I dont think that mechanic was stupid enough to mix the sequence

[Lazydocker]

I dont know actualy It wasn't me who fitted it. I dont think that mechanic was stupid enough to mix the sequence

Don't count on it... Everyone's done it at some point!!!

[perfferle]

Personally, I would go back to basics and check that sparks are present at all the plug wires. You can use an old sparkplug (any type) for this check and have someone turn the ignition keyswitch and crank the engine while you look for sparking for each HT plug lead.
At least you will know if you are getting sparks which is a good start. If not then you may have a fuel system fault.
 

[caolan_p]

It apears that the engine started to run only on 4 cilinders. Doing 10mpg and has no power at all. Very shaky. I have changed coil pack, leads, and spark plugs but nothing got better. Have send ECU to check coz havent got a clues what else might be. EGR works fine. Engine diagnostic didn't come up with any codes. Just dont know what to do. Any ideas???
THAnks

I just put my new coil pack in there now in it is still running as if it still of a cylinder, the computer showed it was of cyl1 and cyl4 last week :(any one els have any other thoughts?

[Markjay]

Did you check the condition of the spark plugs in cyl 1 and 4, i.e. are they oily? And are they in general good order?

Can you do a cylinder compression test to ensure it is not valve or head-gasket issue etc?

[caolan_p]

Did you check the condition of the spark plugs in cyl 1 and 4, i.e. are they oily? And are they in general good order?

Can you do a cylinder compression test to ensure it is not valve or head-gasket issue etc?

 

all new plugs in it...How do i do this - can you do a cylinder compression test to ensure it is not valve or head-gasket issue etc

[Markjay]

Did you check the condition of the spark plugs in cyl 1 and 4, i.e. are they oily? And are they in general good order?

Can you do a cylinder compression test to ensure it is not valve or head-gasket issue etc?

 

all new plugs in it...How do i do this - can you do a cylinder compression test to ensure it is not valve or head-gasket issue etc

The compression test is used to compare the compression between the cylinders. If one or more have significantly lower compression than the others, the reasons could be burnt or leaking valves, or worn compression rings. Adding a spoonful of engine oil into the plug hole and repeating the test will help identify the problem - if the compression rises following the oil addition then the problem is with the compression rings, if it does not then it is with the top part i.e. valves.

Other causes for low or no compression are wrong timing (though this would typically affect all cylinders), or blown head gaskets. If two adjacent cylinders have low compression, it is possible that the gasket has blown between the two cylinders.

The test is done by removing the fuel pump fuse and allowing the engine to idle and die out (you don't want fresh petrol flooding the cylinders and contaminating the cats), then removing all spark plugs, removing the HT leads to avoid spark, throttle fully open, stick the compression gauge into each plug hole one at the time and crank the engine a few times until the reading peaks.

If you have a screw-on compression gauge, as opposed to a press-on one, you can do it yourself and don't need a helper.

The reason for this test is that the engine needs four things (at the right time) to fire: fuel, air, compression, and spark. If one cylinder does not work, then it would typically be due to lack of any of the above....