Jump to content

Misfiring


OneTen
 Share

Recommended Posts

Hi !

First, sorry for my English, this is not my native language. :unsure:

My problem is that my HSE is misfiring. I think it's on the right hand cyl. bank (2,4,6,8).

It starts, but run rough on idle.

What I have check out / replaced, is:

Spark plugs = new (OE)

HT leads = new (Bosch)

Coils = have been testet ok in a work shop

Wires from coils to ECM = ok

Injectors = measured from plug on the ECM through injector to fuse 37 in fusebox, approx. 15 Ohm on all 8

Anyone?

Regards from Norway

Link to comment
Share on other sites

Your English is better then my Norwegian :rolleyes:

A common fault is the the flywheel position sensor has coming loose. Its mounted on a metal plug and can be viewed from underneath. If it has moved then you will clearly see a shiny ring on the plug about 2mm wide. Re-seat the plug using Loctitie bearing seal, making sure you have the correct gap on the sensor.

The ECU will have logged a load of fault codes ................. these will go after couple of days as it adapts to the correct settings

:)

Ian

Link to comment
Share on other sites

Ah yes, the multiplug ....................... I think Land rover employ dwarfs with 0.5 metre fingers :lol:

I think you will now need to read the ECU codes and see what is stored. A big problem is that the ECU is adaptive and compensates for faulty sensors. It would be good to get the codes read and the ECU reset ....................

The other thing to check is the O2 sensors ...............check to make sure the heater is working and that the returned voltage looks correct.

:)

Ian

Link to comment
Share on other sites

It's a 4.6 Thor engine with 2 coils with 4 plug lead points on each. Both coils have been tested with a dizzy in bench.

I have one coil in spare, so I can swap one for a test. I managed to take out both coils without removing upper inlet manifold, so I can do it once more.

Link to comment
Share on other sites

I changed the coil packs today, same result. I have installed new spark plugs. took them out today. Cyl 2 is black, less on cyl 4, even less on cyl 6 and cyl 8 was clean. Cyl 3 is black, less on cyl 3, 5 and 7. I know that cyl 2 and 3 is triggered at the same pulse. Cable from ECM to coil packs are ok. Maybe it's the output from ECM to coil? Connected OBDII reader today, no errors. But then again, isn't so that ECM can't 'see' if the coils are triggered?

Link to comment
Share on other sites

OK …. If you have error codes reported and everything looks OK on the ignition side, then it may be time to look deeper …………..

Do a compression check on the even cylinder bank …………….

You say that No 8 is clean and 6 is not so sooty as 2&4 ……………..get another plug and connect the No lead to it, to see if it is firing OK………….. with all the tests you have done the fault may not be ignition related.

If the plug is firing OK, then check top see if the injector is firing ………

If that is OK and the compression is OK, you may have a slipped liner on the offending cylinder (or cylinders) …………. This also causes misfire, especially from cold and also on a hot restart. This fault will also give a very, very clean plug as it is almost being steam cleaned.

:)

Ian

Link to comment
Share on other sites

Compression test done. I have a dip on cyl 4 and 5.

Approx. 9,5 Bar on these and approx. 11 Bar on the rest.

With a little dash of oil in cyl 4 and 5, I've got 11 Bar on these as well.

Piston rings problem?

Any advice on how to handle this one?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy