My 99 E300 will run fine for miles, and then start sputtering while belching white smoke. You can see the tach fluttering and feel the engine pull then stall, pull then stall about one occilation per second. I think it is too fast to be mechanical and has to be electrical. Maybe a sensor or something. Any ideas?

Thanks,
Ben
(662)648-9157 feel free to call
bhowell_10@yahoo.com

99 E300 262k miles

Hi Ben,

Can you see any air bubbles flowing through the nest of plastic fuel lines? I was having a similar but not so severe problem until I replaced the O-rings in my fuel system. I saw quite a bit of air coursing through the lines before I did the work.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

I must second the idea of air bubbles. You most likely have some bas seals on the plastic fuel lines. You could replace all of the o-rings on each line; however, for peace of mind I would recommend changing all lines for new. You can also use the old prefilter line to perform diesel purges in the future.

Eliminate the obvious chronic source first.

__________________
raMBow

1999 E300DT Obsydian Black Metallic, Heated Full Leather Parchment options, E2, K2, 136,000+, best 36.5 mpg - GP's 12-04 & 11-12 Zero Stuck
2010 Honda Odyssey - The BrideMobile - best 26.5
(2) 2005 Honday Accord- (1 -Corporate 1 - Personal) - 110,000 4-cyl 30mpg
2000 VW Golf GLS TDI, Upsolute Chip (sold to Brother, now 300+k on it) 48.5 mpg like clock work
1987 Honda CRX HF - Sold 87,000 always over 50 mpg Max 67 mpg

I had this same problem this time last year...it turned out my main fuel filter was full of water...just for kicks have it replaced and see if that doesn't cure it. It's the time of year a lot of condensated water collects in the fuel systems so a good time to replace the filter.

__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

For air to be the problem it would have to be a massive influx to cause it to die while running. If such a leak existed one would have to expect you would also be expiriencing hard or no start conditions in the mornings too.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Can't see it being an air leak tbh. White smoke usually is water.

True, or improperly burned fuel. Too cool as opposed to too rich IIRC...

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

I replaced all fuel lines with new less than a year ago due to a leak letting air in. I didn't assume that it was air this time because the problem occurs when driving vs. just starting. With the air once up and running it was ok. I'll check it though. Also I've heard something about a K40 relay, and I'll check the fuel filter tomorrow. Keep the ideas coming. Thanks, Ben

The reason i suspect it is electrical is that I can put the car in neutral, cut the key off and re-start. The engine will then run fine wide open throttle and push you back into the seat with acceleration as opposed to not being able to even go 40mph. So I know that cars ignore some sensor data for the first 60 seconds or so of driving due to waiting on components to warm up. I don't know much about the electricals on this engine. Thanks, Ben

Now that sounds more like the classic MAF fault. No CEL?

Try cleaning the MAF with CRC cleaner made for that purpose. If that doenst help you could try testing per the attached.

http://www.x-desk.net/ximages/21302_pgsi0079en.pdf

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

This is EXACTLY what mine did too...it's the fuel filter, I'm telling you. Mine would run OK for about 5 minutes then start to stumble, crap out and stall with a HUGE cloud of white smoke out the exhaust. I'd restart it and it would be fine after that. The next morning the same thing. After the second day I changed the fuel filter which was full of water...after that never again! I think stopping and starting it would allow enough fuel to enter the filter until the next time it filled up again.

Look, the filter is cheap and easy to replace...try it you have little to lose.

__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

The poster and I have communicated offline....he has bad DV seals not mentioned previously.

Based upon that info, I'd suggest:

1) R & R DV seals (and every other fuel line seal at same time)
2) R & R main fuel filter
3) Clean/test MAF

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

If you do suspect the MAF, don't whatever you do buy from a Mercedes dealer. The insert is a Bosch part, and you can purchase it from a Bosch outlet at a considerably lower price. Its only a plug and 2 torx bolts.

I'm very skeptical that it could be the MAF and you not get a CEL...most of the time you get the CEL without even any symptoms but when the car is running so badly due to the MAF I would think you would be throwing codes left and right.

__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz