GILLY, PLEASE HELP!! - PeachParts Mercedes-Benz Forum

jsliw1376 · #1 04-28-2010, 01:42 PM

My wife drives a 2001 ML320 and a week ago the speedo and tach needles started going crazy, up/down/up down, sometimes freezing in place and sometimes not even moving. Then several days ago the engine light came on. The very next day when we started the car it sputtered and stalled. After re-starting, it was ok but the idle was a little off. We also could not shift it into reverse. So we did the pen trick so we could shift it into reverse/drive. When we did so the idle went way down and the car sputtered but did not stall, when in park the idle gets smoother. The codes that I pulled were P0130, P0136, P0150 and P0156. These seem to be codes for all four O2 sensors. My question is, could all 4 go at the same time? Or is there anything else that could be causing the O2 codes to come on? The plugs, wires, alternator and brake light switch have been replaced within the last 2 years. I really do not want to take it to the dealer since $$ is a little tight. Any help will be greately appreciated, Thank you.

Gilly · #2 04-28-2010, 06:36 PM

Clear em and see if they come back.
Gilly

jsliw1376 · #3 04-28-2010, 07:43 PM

Thanks Gilly. I cleared the codes a few days ago and no engine light yet but the idle is still sluggish. Thanks again.

jsliw1376 · #4 04-28-2010, 08:24 PM

Well, I just came back from the store and the engine light is back on. I checked the codes and this time it came back with P0130 & P0150. I think I will start with replacing the CPS and two front O2 sensors. the car is almost at 100k so I would think it would benefit from new O2 sensors anyways. thanks

Gilly · #5 04-28-2010, 10:03 PM

Right, and the rear ones won't affect driveability, they only are used to monitor if the cats are working.
Gilly

lkchris · #6 04-29-2010, 09:07 AM

Most of the time the O2 sensor code indicates a bad MAF.

The fact that the exhaust mixture that reaches the sensor is something the sensor can't handle doesn't mean the sensor is bad.

Gilly · #7 04-29-2010, 11:20 AM

But isn't there a code for mixture rich, not a fault of the o2 sensors?

I also believe he'd have the fault for the maf sensor out of range as well, although I know you don't always get that code.

It would explain the driveablity issue though.

Gilly

jsliw1376 · #8 05-01-2010, 03:11 PM

Thanks guys. My wife had to take the car the other day and it stalled while she was driving, tried re-starting and after a few attempts it finally started back up. So today I replaced the crankshaft position sensor and swapped the battery out of my truck and started it up, it ran for about 30 seconds and stalled out, all dash lights went out for a few seconds and then came back. Also, the speedo and tach needles do not even move, they shudder right before the car stalls out. Car will re-start with no problem but runs for about 30 seconds before stalling. I don't even know where to look next, I might have to suck it up and take it to the dealer. Any ideas on what to check next? Thanks again.

Gilly · #9 05-01-2010, 10:05 PM

Fuel supply. There is a port on the left side fuel rail that's capped and with a schrader valve underneath, when it quits, you can have that cap ready to come off and see if there is fuel pressure at all.
The gauges I am not sure what's going on.
If not the fuel pump iself, the pump could also be losing electrical power due to a lousy fuse board.
Gilly

jsliw1376 · #10 05-01-2010, 10:32 PM

Thank you Gilly! I will check that out next. I have been thinking of replacing the fuel pump(updated version) assembly for a while now, the fuel gauge has not worked in years and I am sure it is due to that entire assembly. BTW, how does the car have enough fuel to start up and stay at idle for the 20 seconds that it does? Thanks again Gilly, your help is greately appreciated! I will post later on any progress.

Gilly · #11 05-05-2010, 08:58 PM

Only answer I have for that is there might be enough residual pressure in the lines and rail to let it run that long? Dunno for sure. One of those things where a little hands-on would help a lot.
Gilly