geo1400

I have this strange problem that only occurs every now and then with my 1999 E55.

I live in Dubai so I don't know if you can class this as a "cold start" cause the engine temp is a quarter up as soon as I start the car in morning.

I start the car in morning and let it tick over for a couple of minutes then go. There are two speed bumps on the way out my complex and as I slow down to approach the bumps, the engine stalls!! And i'm usually half way over the bump at the time. It's quite embarassing because I get a bit flustered with panick!!

Like I said though, it only does this 1 out of 4 times, but i'm worried incase there something is seriously wrong.

Anyone had any experience with this before?? The car is telling me a service is due but i'm not sure it is that simple...

Thanks in advance

MercedesElite

We have seen something like this at the dealership it ended up being a bad MAF sensor could you tell me more about the problem does it re-start ok? or does it do it under any other conditions? CEL on?

geo1400

Thanks for you responce Mercedeselite,

No CEL light, only "service due". It starts without a hesitation after it cuts out. And like I say, it has only happened on the speed bumps going out in the morning (which would suggest to me it's because it's cold?). It's weird I can feel it's going to happen, I brake (in gear/drive) approaching the bumps and the revs just drop right down to about 300rpm and then it just cuts out and the lights come on.

After i'm over the bumps, I drive the car at a resonable speed for about 1 km and then break for traffic lights with no problems.

I checked through the service records for the car and the MAF was replaced about 2 years ago max (not sure exactly because it's in Arabic!!) or maybe 20000km ago.

Thanks again.

ohlord

with a obd2 port under the dash?Can you get the codes read and see if any are pending?
Now tell us does it stall when you hit the bumps or as you slow to approach them?
Have you checked that the maf is fully plugged in? also the cam position sensor located on the passenger side front of the head.If you started it in the morning and just drove off without warming it up for a few minutes does it happen?
The speed bump issue is interesting because if it happens going over them it may be a vibration issue such as a loose harness or sensor.
Tell us more
ohlord
"GOT CODES?"

geo1400

It happens over the same bumps in the morning and generally as the front wheels hit and go over the bump. It hasn't happened (touch wood) on any other bumps or anywhere else than the first two in the morning. It done it again this morning.

I don't think there is a difference between warming up or from cold to be honest. I let the car tick over for about 5 minutes this morning and it still done it. I'll the connection to MAF and Cam sensor tonight. My car is LHD, does that mean the Cam sensor is on drivers side?

As for the codes?? I'm very new to this MERC business so wouldn't know how to get codes without going to dealers. Is there a special tool available to read codes?

Thanks again for your input OHLORD.

Geo

geo1400

Ok something new happened this morning. I got passed the speed bumps with no problems then at my first set of lights the engine stalled, ignition lights came on and the words "battery recharge" came up. I'm almost possitive that's the first time the Battery warning has come up.

Now what? any different?

I'm a bit worried because my wife is visiting at the moment and I don't want the car to die on me in this desert sun!!!

Cheers

geo1400

I've not had a chance to get this problem checked out yet so untill then i'll keep posting when something new happens, just to see if it becomes familiar to any of you guys!

Last twice i've tried to start it took 2 attempts. Both times the engine turned over but just coughed and spluttered a bit. I also got the BATTERY RECHARGE sign again.

Does this sound like a battery problem? I've got reciepts showing the battery is only about a year old?

Thanks

Geo

benz-tech

lift the rear seat and make sure the battery connections are tight and for that matter wiggling all grounds and power points might reveal something loose. also, make sure the air intake tube from maf sensor to the throttle body is tight and sealed. HTH

victorylap

i had problems where my car would stall while at a stop light - i learned to find out that i had a faulty crankshift position sensor - luckily, i had it replaced for free while under my starmark extended warranty - good luck.

geo1400

I've been told it may be the Crank Position Sensor... I've booked the car in to Mercedes tomorrow for a check up anyway. Hopefully the check up will reveal something simple that I can have fixed elsewhere or even DIMyself!!

I'll post results.

Thanks

geo1400

Hello again,

Never took the car to Mercedes, turned out I can get a full check up done somewhere else for about $120 instead of the $600 Mercedes wanted for a minor service and full check.

But, found something else today, check the "Quick help NEEDED" thread also posted by me.

Turns out one of my injector cables is chewed, could this cause my symptoms?

Sorry for my persistance but I think i'm onto something!

Cheers

geo1400

Just got the car back from the check up and apparently it's the MAF, they wanted about $400 to replace it so I was just straight with the guy and told him i'm going to DIY cheaper.

So before I hunt for a replacement i'm going to try clean it as per instructions on benzworld. Here's my question though: Do I have to use specificly MAF cleaner? I've searched in a couple of shops for this type of thing and found nothing. What about CARB and CHOKE cleaner? or anything else?

Thanks

Holmes5518

Buy electrical contact cleaner.

geo1400

For those who suffer from the above symptoms... replace the MAF sensor. After cleaning it seemed a bit better to start but then got a whole lot worse, replaced it and it's fixed (touching wood).

For those who have done this job before, did you notice less of a kick down effect when accelerating hard? I noticed since i've had the car back that when press full throttle (not often!) it just seems to accelerate smoothly through the gears, whereas before it kicked down a gear hard and accelerated. Any ideas why that might be?

Thanks for all your help so far!

whoover

If the MAF is sending the ECU wrong information about air flow into the engine, it will not be able to determine the correct gear to downshift into. It probably thought your manifold vacuum was lower than it was and downshifted into a lower gear than was appropriate. Now it's back on track and downshifting one gear instead of two.

geo1400

Whoover that makes sense. Even though with the old MAF the kick down effect was stupidly fast and harsh, it very often red lined very quickly - almost inappropriatly.

I'll drive it some more but it is actually very smooth now.

Thanks for the Positive reply!!

Geo