clean exhaust outlet - whats wrong?

[hermi500]

Hello,

i want to change the mainfold exhaust gaskets at my chimaera and was very surprised, that the exhaust outlets from zylinder 3 was totaly clean and the outlet from zylinder 6 was nearly clean. all other outlets are normal a little bit sooty.

It seems that they will be to hot? please take a look at the pictures.
for a large picture click at the link below.

please can any give me some suggestions about the reason?



http://img222.imageshack.us/my.php?image=banklinksmr7.jpg 


http://img88.imageshack.us/my.php?image=bankrechtsnq6.jpg 


Zylinder 3/6

http://img407.imageshack.us/my.php?image=zylinder3eg7.jpg 


http://img182.imageshack.us/my.php?image=zylinder6jv8.jpg 

Zylinder 1/4

http://img144.imageshack.us/my.php?image=zylinder1ow2.jpg 


http://img413.imageshack.us/my.php?image=zylinder4vg7.jpg 

left spark is from zylinder 1 and right spark is from zylinder 6

http://img182.imageshack.us/my.php?image=kerzenre3ra6.jpg 


thanks
Hermann

[Tahiti450]

Looks like cylinders 3 and 6 are running lean, the others look pretty normal. The plug appearances would support this. Since the fuelling isnt controlled on an individual cylinder basis and only 2 separate cylinders are affected its unlikely to be any problems with the ECU or lambda sensors, I would direct first investigations towards the injectors. If these two injectors are partially blocked or malfunctioning it is conceivable that they could be under-fuelling the two cylinders to the extent that there is sufficient heat in the port to burn off all deposits. If the plugs on the affected cylinders are very white or glazed then that would fit. Alternatively an air leak on the inlet tracts to these 2 cylinders would lean out the mixture and probably also cause idle speed problems.
Have your tried running a diagnostic on the ecu to check for fault codes?

Edited by Tahiti450 on Saturday 26th January 19:42

Edited by Tahiti450 on Saturday 26th January 22:28

[Barkychoc]

It wouldn't be anything as drastic as this would it?

Not losing water are you?

http://www.rpiv8.com/engine-4.htm#inside

Scroll right to the bottom - then up to the picture above the dyno graphs & read accompanying text next to it & above.
I don't pretend to know what I'm talking about on this so feel free to shot me down in flames, I just remembered reading that a while ago.

Chris

Edited by Barkychoc on Saturday 26th January 20:54

[GreenV8S]

Is it running OK?

[Tahiti450]

Barkychoc said:

It wouldn't be anything as drastic as this would it?

Not losing water are you?

http://www.rpiv8.com/engine-4.htm#inside

Chris

Good point, hadnt thought of that but I guesss if this was an instance of the dreaded cracking-behind-the-liner and water getting into the combustion chamber during the induction stroke that could account for steam cleaning of the ports. I dont know how common it is to get 2 separate cylinders affected in one block though?

Are there any cooling system problems, excessive pressurisation and water loss particularly?

[hermi500]

Thanks for the answers!

I have only little problems with water leakage. they can solved by tighten the pipe clamps. the last 1000 km i only must top up about 50ml - 100ml water. i think this is not much and may be also a result of a temperatur difference from the water at the moment of checking. i hope you are not right with moved liners or cracked block.

i read out the error code from the ecu with a prc7067. it shows "88" - i mean this stands for power up check.

is it running ok? - i can't answer the question with a clear "yes" or "no".
it is a sneaky process and i think it will be running better some month ago. and sometimes the idle is a litte bit lumpy. it feels like a unbalanced mass in the engine. so it sounds logical that two consecutive cylinder running lean and have less power.

i think the best next step is to test the injectors.
had anybody done this by himself?
has a chimaera 5.0 also land rover ERR722 injectors from lucas?
are there possible alternative injectors e.g. from bosch ore other manufacturers?

thanks
Hermann

[Philr]

Herman,
I'm not an expert here, but I have heard that bosch injectors are the next logical choice. However I seem to recall that this also required changing the AFM (or was that removing it ?) and I guess that this would also need an ECU remap.

Mark Adams seems to be one of the main advocators of the bosch injectors.

Phil

[GreenV8S]

I've put together a crude rig to test injector flow rate and spray pattern, but unless you're happy playing with explosive vapours and fuel under high pressure it's more sensible to send them away for checking/servicing.

[Tahiti450]

hermi500 said:

......... idle is a litte bit lumpy. it feels like a unbalanced mass in the engine. so it sounds logical that two consecutive cylinder running lean and have less power.

i think the best next step is to test the injectors.
had anybody done this by himself?
has a chimaera 5.0 also land rover ERR722 injectors from lucas?
.......

thanks
Hermann

Interesting point about the ? misfire on consecutively firing cylinders, It would be worth checking the distributor cap as a first, easy investigation. It is conceivable that if there is a genuine misfire due to poor spark (? a crack or tracking on the dis' cap between 3 and 6, or damage / deposits on the HT posts) then lots of unburnt fuel leaving the cylinder could also wash the ports clean?

As far as injectors are concerned I am not sure whats on the 500 but I would not be surprised if they are the standard LR items. Rather than pondering about alternatives you need to know if there is a problem with the injectors in the first place and service / replace as required.

[Ordinary Bloke]

GreenV8S said:

I've put together a crude rig to test injector flow rate and spray pattern, but unless you're happy playing with explosive vapours and fuel under high pressure it's more sensible to send them away for checking/servicing.

[dlewis]

My 88 fault was a dirty purge valve electrical connection.

This would not cause these symptoms though.

Have you checked for any other codes being output (lower priority) per the code reader instructions?

[blitzracing]

If the engines back in one piece invest in a couple of colour tunes,(Personaly I love the things, you can see whats going on without guessing, I have 4 to see a bank at one time) and compare the mixture burn colour between good and bad cylinders. Hopefully there should be enough intensity or colour difference to show up. Then swap the injectors and see if the fault moves. Fault code wise the ECU is not that sensitive to lean mixture, as it monitors 1 bank at a time, and all 4 cylinders will have to run lean to get it to consistently drop below Lambda 1. Its unlikely 1 bad cylinder will make this happen. Also what about a compression test?

Mark

[hermi500]

Thanks at all!

@dlewis: i read in the "bible" about the code 88 as possible purge valve fault. then i first check the valve and it is all right. so i think in my case the 88 stands for power up check and i don't try to read lower priority errors. at the moment the car is without a battery so the ecu is cleared :-(

@greenv8s: sorry but i don't know what's a "crude rig". please can you explain it?

to use colour tunes is a good - sadly expensive - method. i try this if i have no success with other ways. new distributor rotor and cap are ordered :-)
but i think anyway i should check the injectors. what is the right way to dismount the injectors? pull it out with mounted high pressure line or first disconnect the high pressure line and pull it out separate.

and again - hope somebody know it sure:
has a chimaera 5.0 also land rover ERR722 injectors from lucas?
are there possible alternative injectors e.g. from bosch ore other manufacturers?

best regards
Hermann

[Barkychoc]

Its a lot of dismantling but you could move the injectors to other cylinders to see if the problem moves or stays where it is.

My money is on ignition - especially as someone pointed out they are consecutive firing cylinders - I'd replace the distibutor cap, rotor arm (genuine lucas) and leads for starters.

If you want to be scientific about it change one thing at a time, I'd start with the distributor cap.

There is also some info in the Range Rover manual I have about the routing of the HT leads - and that misfires can be caused by HT leads running too near each other. I can post a pic up of this if it would help.

Chris

Edited by Barkychoc on Monday 28th January 21:49

[Tahiti450]

hermi500 said:

Thanks at (to) all!

.......... what is the right way to dismount the injectors? pull it out with mounted high pressure line or first disconnect the high pressure line and pull it out separate.


best regards
Hermann

Remove the fuel pump relay and start the engine (without the pump running). It may fire up briefly and stop or just not start depending on how much pressure was in the fuel circuit. This should get rid of most of the residual fuel pressure and make the operation a bit safer with less fuel slopping about. Remove the coil, breather hose , AFM elbow and plenum chamber with base. Then carefully disconnect the fuel lines over the R rocker cover at the back, pack rags / tissues under them to soak up the fuel which will spill. Remove the four nuts holding down the fuel rail then gently work your way around the injectors coaxing the seals out of their registers until they are all free then lift away the fuel rail and injectors. The injectors can then be separated from the rail by removing the spring clips and again gently coaxing the seals away from the rail. Take the injectors to a local fuel injection service agent and have them checked for operation, sealing, flow rate and spray pattern. Preferably get them ultrasonically cleaned, replace any faulty injectors and then refit with new seals.

I've included a pic of my engine showing the fuel rail with the plenum removed.

[URL=http://rides.webshots.com/photo/2373523980057726950YZQDFw][/URL]

Edited by Tahiti450 on Monday 28th January 22:19

[GreenV8S]

hermi500 said:

@greenv8s: sorry but i don't know what's a "crude rig". please can you explain it?

It's a test rig I made which is not very elegant but lets me test the flow rate and spray pattern of each injector. This is not something I'd recommend as a casual DIY and if you need to ask how to do it the chances are you would be better off getting them serviced professionally.

[GreenV8S]

Tahiti450 said:

Remove ...

The two most important bits IMO:

1. You don't need to disconnect any fuel hoses, but a cup full or so of fuel will come out when you remove the injectors from the rail. Fuel vapour can be highly explosive so be very very careful about any spills, make sure you are working in a well ventilated place with zero chance of electrical sparks, nobody welding next door etc.
2. Once you have loosened the plenum top, be absolutely paranoid about dropping dirt / parts / tools into the exposed trumpets. Mask them off as soon as possible. If you drop anything in and notice it you may have a right old game getting it out and may end up stripping the heads off. And if you drop something in and don't notice, there is a definite risk of lunching the engine when you go to fire it up.

Edited by GreenV8S on Monday 28th January 22:21

[Tahiti450]

GreenV8S said:

Tahiti450 said:

Remove ...

The two most important bits IMO:

1. You don't need to disconnect any fuel hoses,

1. Once you have loosened the plenum top, be absolutely paranoid about dropping dirt / parts / tools into the exposed trumpets. ........

Edited by GreenV8S on Monday 28th January 22:21

Quite so Peter, thanks. ....I didnt think about the fuel hoses since we are just removing the injectors, but it does mean you can take the fuel rail off complete and dismantle the rest on the bench.

And YES when i looked at my post I thought i should have pointed out about the perils of open inlet manifolds. I should point out that I left mine uncovered just for the photos then taped them up!

[spend]

Tahiti450 said:

I should point out that I left mine uncovered just for the photos then taped them up!

Now where's that bloody lens cap gone!

Dave

[Tahiti450]

spend said:

Tahiti450 said:

I should point out that I left mine uncovered just for the photos then taped them up!

Now where's that bloody lens cap gone!

Dave

..... bu**er, where's it gone!

Just as well i got that new endoscope then.... Nuuuurrrggh

Now i can look anywhere ,.... can even look right up my own ar** !