Power loss SL 320 v6

[Pipemaster]

It always seems when you change your car all the bits that were about to go wrong.... do.

I have a SL129 320 V6 2000 reg. I have just changed the Air Flow Meter as the engine mangement light was coming on and the previous owner had changed both CATs in October last year and the note on the garage invoice stated if the light came on then the AFM should be changed. It did and I have. Now I am getting an intermittent loss of power. Coming home tonight at 0.5 C (I am not sure if thats relevent) and on a dual carriageway the response was non existent but later it picked up. I had a coil go on my last SL a 280 and this reminds me of when that was on its way out. I have read a couple of threads on here about cutting out at 4000 rpm but this is way less than that. The thing is that it can run OK so could it be dirt in the injectors or poor plugs ( they were changed in the last service) or is it the coils?
I have had the car a couiple of weeks and it was standing for about 6 weeks before that.
Any suggestions welcome

 

[television]

Just gatting this one up front for the morning.

malcolm

 

[Pipemaster]

Just a thought could the AFM be faulty? It wasnt oem

 

[stats007]

There have been a few people caught out with non-OEM MAF sensors. When cold the MAF is bypassed anyway so you should be able to work out if it's working or not?

I would be careful of driving it too much if it's running that badly - the cats really don't like it.

Have you checked the fuel supply and filter? Another V6 owner had water in the fuel that affected one cylinder.

 

[Pipemaster]

Thanks Stats. I was concerned about the CATS but it was just on 1.5 degrees coming back from the office yesterday so it wouldn't be the MAF then I had only just gone about 1/4 mile
I will have the fuel filter checked as it was very low on fuel whilst it was standign but I have gone a few hundred miles since then.

 

[television]

The last 129064 car that we had behaving the same as yours turned out to be a poor connection to the gearbox ECU situated just above the selctor.

This was CAN BUS related and was a pig to find, on this car fault codes were being thrown up all over the car. Its been perfect now for over one year.

Malcolm

 

[Pipemaster]

Really! well i will definitely have to look at that one, thanks Television

 

[television]

I will find the link later in the day, just to say that MB never found the fault,thats why the car got sold, seems only to effect 2000-1 cars.


Malcolm

 

[Pipemaster]

I have just been on a 300 mile run and noticed that the car only has the problem between 3 and about 3.75k revs. I realised at about 100 mph showing about 3.75 revs (I think as the rev counter face i have just noticed is a little on the cock anti clockwise) it feels just like the kick down is trying to operate. Could this be the KD switch on the pedal (if that's were it is) or is the engine management system in cotnrol of that and in need of remapping perhaps?) The car doesnt have any problems when I select 4th 3rd 2nd etc arcoss the rev range.

I also remember - due to Televisons posts - that when cold the engine has a cuto out at about 4k rpm until warm which expalins why the total loss on one early occasion when the car was cold.

 

[Pipemaster]

woooohoooo!

Just an update. After having the MAF changed and still having a problem with the power put the car on diagnostics showed NEW MAF was faulty- after a 300mile trip!!! SO put another one in and the car ran like a bag of nuts for about 10 minutes. Turned it off went out later and Bob's your uncle Fanny's your aunt smooth as the proverbial. A discussion with the Stealers mechanic said - yes.. later models are self mapping and sort themselves out once you change the MAF and run it for a bit...
He may be blowing smoke up my @rse but I dont care It works!!! :grin:

 

[Uncle Benz]

Out of interest, have you now fitted an OE MAF sensor? Will you name the brand of sensor that was faulty? *cough*

 

[Pipemaster]

Out of interest, have you now fitted an OE MAF sensor? Will you name the brand of sensor that was faulty? *cough*

The new MAF wasnt OE and the duff one was branded "Target" but I suspect that it is probabely from the same factory!

 

[stats007]

Doubtful. All Bosch MAS designated for MB are stamped as such. A Chinese copy is more likely.

 

[Pipemaster]

Hi Stats. What I was saying was that both non OE MAFs were from the same factory not the MB as I didn't use and OE product

 

[stats007]

Still confused Steve

 

[Pipemaster]

The MAF that was faulty after the initial diagnosis of the OE MAF fault i.e. the original probelm was replaced with a MAF branded "Target" this turned out to be faulty too and wa sreplaced with a further non OE MAF which worked. I was saying that whuilst the two OE MAF's were not the same brand they were probably made in the same place and just branded differently... clear as mud now I guess?? LOL

 

[television]

I always have my doubts on these important items where they are copies, the Bosch correct inserts are only £58 each.

Malcolm

 

[Pipemaster]

I always have my doubts on these important items where they are copies, the Bosch correct inserts are only £58 each.

Malcolm

when you say inserts is that within the plastic housing or the whole unit. I think if I had known it ws only £58 i would have used Bosch but the dealers quoted in excess of £300 to supply and fit and i know the job is only 15 mins at the outside so I assumed the OE were going to be very expensive - you live and learn as my old grand mother used to say snowboarding in the alps :-D

 

[television]

Yes from any local Bosch agent,you just put the unit into your own plastic housing,very simple to do.

Malcolm

 

[Pipemaster]

OH BUM

(Thanks for the info though)