SL320 Cylinder 5+6 Misfire

[GregE240]

Raj, what Nav is saying is empty the defective cat, then chuck it back on the car. If the mis fire disappears, then job done; order yourself some new 'uns and be satisfied that you're replacing the defective part(s).

How are you going to feel, a bag of sand lighter, 2 new cats on the car and a misfire?

(I think thats what he's saying anyway)

Greg

 

[KLP 92]

Raj, what Nav is saying is empty the defective cat, then chuck it back on the car. If the mis fire disappears, then job done; order yourself some new 'uns and be satisfied that you're replacing the defective part(s).

How are you going to feel, a bag of sand lighter, 2 new cats on the car and a misfire?

(I think thats what he's saying anyway)

Greg

Thats exactly what i'm saying. Best bit about doing it this way is that the car can still pass its MOT on the one CAT, i've seen it done on a CLK320 before. Its the easiest and cheapest option!

I've had a CAT cut open and emptied before, and then welded back again. Cost £60, saved me a CAT and still passed its MOT.

 

[rajinder_1]

but doest that make it noiser as you have removed some of the padding between the engine and backbox....

 

[KLP 92]

but doest that make it noiser as you have removed some of the padding between the engine and backbox....

Hardly noticable, a slighlty deeper note. Sounds better IMO.

 

[stats007]

It would probably work in the short term but I wouldn't like to run one bank of cylinders through a cat with different back pressure to another for very long.

 

[rajinder_1]

knowing my luck i would probably do it and end up doing more damage to the car. thanks again guys

 

[rajinder_1]

guys quick update, got the cats and guess what, there are NOT Eberspecher as described to me on the phone, now i will have to return them and order some from another place......
Why would you tell someone that they are one brand when the cats are labeled with another (BM)....

Cant believe KMS though such a large company and trying to blag me into forking out nearly £1000 on cats which i had been quoted £700 for..... then trying to make me think taht eberspecher make the cats for BM????? mmmmmm i dont think they will be getting my custom in the future, cheeky S***s even made me drive to the b'ham office to return the cats which they mis sold to me.....
Why why why would you mess somebody around who is about to give you business.....and a grands worth aswell..... go figure???

Raj

 

[rajinder_1]

cats look smaller???

hi got the cats from GSF and they look really small compared to the ones on the car????

what should i do? fit them or not?

Raj

 

[rajinder_1]

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got new star diagnostic, po300 and po306 error codes on cylinder 6..... new cats on there aswell,

 

[grober]

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got new star diagnostic, po300 and po306 error codes on cylinder 6..... new cats on there aswell,

Sorry to bang on about this but have you checked and replaced the spark plugs on the offending cylinders yet???

 

[rajinder_1]

but surely can a spark plug cause so much, it blew out the left pre cat and caused mutiple cylinder misfires,if it was a spark plug should it not just show on that one cylinder? after being on star appears to be cylinder 6 injector which is running too high compared to the other cylinders. although i will mention to my mechanic to check aswell.

 

[w124coupe]

Make sure you fix the real problem quick before you lose another cat! They can't take rich running as the excess fuel detonates in the cat and suddenly you will have a blockage or a rattle (again). Can happen in as little as 20 miles.

 

[rajinder_1]

cars in with the mechanics so hopefully they resolve it and find the culprit

 

[grober]

If a faulty plug was allowing unburnt fuel into the exhaust then its a possibility. If the car was misfiring on cylinders 5 and 6 as you said in your original post then replacing the plugs is a "relatively" easy operation working on the principle of checking all the basics are working first, before looking for more complicated faults. Looking at the state of the plug tips may also help in diagnosis of the fault. Hope you get it fixed soon Good luck.

 

[rajinder_1]

Hi guys another update, found that the fault is originating from cylinder 6, have had the faults wiped from the car and ir revs and drives fine for about 5 mins then starts to misfire. It seems that cylinder 6 is out as a test was done on star and showed it runnibg a 3.95 to 4.65 all the other cylinders ran at
-0.22 or 0.00 the tolerance on the cylinders is 2.95.

They are now thinking it could be a faulty injector causing the misfire as it is fine when the faults are all wiped the error codes are showing as a capital F aswell?????

any suggestions or ideas???? is it the injector?

Raj

 

[Vlad]

[any suggestions or ideas???? is it the injector?

Raj[/QUOTE]

Or the ECU

 

[rajinder_1]

But would a ecu fault show on just one cylinder? ( cylinder 6)

 

[Dieselman]

Swap the injector to a different cylinder. Either the injector tip could be damaged, the solenoid sticking open, a short to earth on the wiring or the ECU.

Have you tried a strong dose of injector cleaner to ungum the needles?

You should check the dwell on each injector and perform a spray test on each one.

 

[rajinder_1]

I was with the guy from MB yday and he was going to swap the injector over to see if its a faulty injector in 6 causing the misfire.
He did pre warn me that there are orange plastic seals which sometimes snap in the process. we got one side of the injectors off and one of the orange seals got left behind, so he fished that one out with a pick (luckily).
Then we took the other side out and 2 of the damn things got left behind. What could be worse...... well ill tell you, we couldnt see them to fish them out so not the mainfold has to come off to take the seals out as you cant buy them seperate you have to buy whole injector, AND if they are not there the head has to come off!!!!!!!!!!! mmmmmm 15 hrs labour start to finish they think!!!!!! not good im feeling kind of faint......

WHYYYYYYYYYYYYYYYYYYYYY!!!!!!!!!!!!!!!

Raj

 

[rajinder_1]

Does anyone know if the plastic injector seal can damage anything if left in the engine? as explained earlier they have come off when removing 2 of the injectors. or will they have to be removed???