Maybe its not the MAF sensor after all, a short story.

[PJayUK]

For those that have read and responded to my thread about the MAF sensor on my W220, thank you. Here is a slight update, for comments really...

I drive my beloved long wheel base S320 every day into work, about 60 miles round trip and she normally never misses a beat, even though were coming up to 117K. I have spent a fair amount on the beast this month its had a new transmission oil filter, tranny fluid change, propshaft couplings and a fair amount done on general bits and bobs around the car. About 700 quids worth all at a very reputable local merc specialist in Surrey.

I got into the car on Monday after not using it since Thursday last week, and started it up. It coughed and spluttered a bit, fired up and sounded a like a London taxi. Got a bit better as it warmed up, but felt a bit strained on the M25 (not that I ever get much above 60 on the M25). I thought my trusty friend was sick, really sick.....

Stay with me!

I drove into work ok, and once on the motorway it started to feel a bit better but was still a bit lumpy when idling in traffic. So once safe and sound at work I got onto the phone to get some advice. What I was told was, that it sounded like a MAF sensor or moisture in the fuel rail. Now it had been throwing it down last weekend pretty much non-stop so the mosture problem sounded feasible, but being having a tendency to over analyse these things in my mind it was the MAF sensor.

Anyway this is getting a bit long now, so I'll cut it short....

Got back into the car at 5:30 and guess what... started up, and the rough idling was gone, no more London taxi, and the car felt as it should. I have run it all this week and the problem has not come back. I am seeing 31MPG, have smooth idling, kickdown seems fine and there doesnt appear to be any flat spots.... Although it still feels a little laboured, but then I think I am just being paranoid now....

All I have done is filled it up with a full tank of differant fuel (Shell rather than Texaco. I was thinking of throwing a tank of Optimax in.... maybe next time!) and added a dose of Comma PetrolMagic just cos' I can.

All in all slightly confusing and I hate intermittenet faults. But I am loathed to shell out the dosh for a new MAF if mine will hold out for a few more months! The moisture thing sounds a little odd, but possible, I have an intermittent bulb failure malfunction pop up when its wet also.

Anyway, that's me I feel better for getting that off my chest and sharing my weeks experiences!

Any comments, views or advice would be gratefully received!

 

[BlackC55]

I suspect the fault will come back.

Have you thought about the possibilty of a lambda sensor beforming a bit on the lazy side?

 

[PJayUK]

Havent to be honest.... Given that it was hooked up to diags only a week or so ago surely this would have shown up? Dont know much about Lambda's can they just go like that?

 

[x332race]

Would be careful about over analyzing things.....This sounds like a dodgy tank of fuel to me.

I had a BMW 328 that had what seemed to me to be a slight missfire or regular hesitation..I over analyzed it and started replacing things like Lambda senosrs (as I though they were lazy) etc......turned out I had an imperfection on a rear tyre that was causing a vibration that seemed to me to be a missfire! Changed the tyre and the car ran perfectly....spent all that money when I did'nt need to...you live and learn.

 

[PJayUK]

That sounds familiar!

I guess I just quite like this car, and want it to run well but its so easy to jump to conclusions. The if it aint broke dont fix it motto seems useful here, and quite frankly after this month my bank account is a bit broke anyway!

Funny what you say about the BMW you had, I have been listening out for any slight change in the usual sound since this. I have heard many things from rumbles to squeeks, knocks and whistles this week!

I guess I could either give a briefcase full o'cash to my local MB tech or just turn up the new AC/DC album and enjoy the ride (Black Ice, great album by the way!)

As my tech pal once said "its got more sensors on the bloody thing than a Vulcan bomber, it will let you know when somethings wrong"

 

[Dieselman]

I got into the car on Monday after not using it since Thursday last week, and started it up. It coughed and spluttered a bit, fired up and sounded a like a London taxi.

That sounds like damp HT leads and boots to me.

 

[lynall]

Yep i to am listening to the new ac/dc album to, excellent




Lynall

 

[PJayUK]

In the old days, when damp was a problem a good squirt of WD40 on the distributor cap, leads etc tended to help. Would that help in this situation if it happens again?

Just thinking a of giving the HT leads etc etc a good spray when its looking like it will be damp.

 

[x332race]

Just thinking a of giving the HT leads etc etc a good spray when its looking like it will be damp.[/QUOTE]

If you can seem them.....they are hidden below the engine covers n my car!

 

[PJayUK]

They are on mine, too. But you can see the ends that go into the spark plug sockets just enough to give them a good squirt!

 

[sweeper]

just a thought, i used to run a Golf MK2 Gti, every now and then a hydraulic tapet used to sink to a point that it wouldn't run properly on that cylinder, giving rough idle and sluggish performance, come to think of it my old Porsche 944 used to do the same, other thoughts were a coil pack packing up, forget squirting leads with wd40, if they're failing they neeed replacing, keeping them clean is better than covering in water dispersant, which tends to attract dirt and makes tracking of the spark easier.