2001 ML 320 runs poorly or not at all
07-19-2010, 03:59 PM
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ML 320 - 2001
2001 ML 320 runs poorly or not at all
It’s Monday and the car barely runs. We've got a 2001 ML 320 with 155K on her. Last Thursday my wife ran out of gas, but happened to be near enough to a gas station to roll right in to a pump. She filled it up, but it barely ran enough to get home. The engine popped, backfired, stalled repeatedly and then, with a gentle foot on the gas made it the last 10 miles without incident. I called Mercedes the next morning when they opened and they suggested additive for a possible water problem. Didn’t help. They are so booked they wouldn’t have been able to work on it till this week.
We headed into town on Friday and when we started the car again and pulled onto the highway the engine stopped and wouldn’t start again. Towed to Mercedes at 5 PM, no techs left working, but the service manager checked all the codes and symptoms, and said maybe the crankshaft positioning sensor was at fault. I bought one for $129, then drove our loaner back to the shop at night when the car had cooled, drove home and 10 minutes later had the new one installed. Didn’t change a thing.
No loaner today, but the next guess ( not time to hook it up to their scanners today) is the mass air flow sensor. Dealer wants $417 and I can get a Bosch online for $135. But we need our car! Makes me not want to buy parts there again. I had no idea the markup was so high. No wonder they can afford to loan us brand new convertibles! But they did stay an hour late on Friday trying to diagnose the problem for us.
Seems running out of gas had nothing to do with this problem. I removed the MAF and cleaned it. Instead of endless cranking the engine starts right up, but still barely runs unless you are very gentle on the accelerator. It’ll go 60, but takes forever to get there. When you park and try to start again a short time later, it may or may not start, but will stall, and seem to have no gas making it to the engine. When the engine is cold it works almost like it should, but not quite.
Don’t have a tool to read codes – maybe it’s time, if I could only get to a parts store and back again. Ideas welcome! What does this sound like? I've read so many posts here, but can't pinpoint this.
We headed into town on Friday and when we started the car again and pulled onto the highway the engine stopped and wouldn’t start again. Towed to Mercedes at 5 PM, no techs left working, but the service manager checked all the codes and symptoms, and said maybe the crankshaft positioning sensor was at fault. I bought one for $129, then drove our loaner back to the shop at night when the car had cooled, drove home and 10 minutes later had the new one installed. Didn’t change a thing.
No loaner today, but the next guess ( not time to hook it up to their scanners today) is the mass air flow sensor. Dealer wants $417 and I can get a Bosch online for $135. But we need our car! Makes me not want to buy parts there again. I had no idea the markup was so high. No wonder they can afford to loan us brand new convertibles! But they did stay an hour late on Friday trying to diagnose the problem for us.
Seems running out of gas had nothing to do with this problem. I removed the MAF and cleaned it. Instead of endless cranking the engine starts right up, but still barely runs unless you are very gentle on the accelerator. It’ll go 60, but takes forever to get there. When you park and try to start again a short time later, it may or may not start, but will stall, and seem to have no gas making it to the engine. When the engine is cold it works almost like it should, but not quite.
Don’t have a tool to read codes – maybe it’s time, if I could only get to a parts store and back again. Ideas welcome! What does this sound like? I've read so many posts here, but can't pinpoint this.
Last edited by Curzon; 07-19-2010 at 04:02 PM. Reason: spelling errors.
07-19-2010, 10:01 PM
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ML 320 - 2001
Won't even start now.
Drove this car 30 miles this morning. Started six times. Moved it out of the garage one hour ago, and loaded 3 kayaks on top. Won't start now and had to roll it back in the garage for the night. I even tried what the Mercedes techs suggested and what I read online here: disconnect the wiring to that sensor. Nothing. Ordered a mass air flow sensor that will be here on Wednesday.
07-21-2010, 01:22 AM
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ML 320 - 2001
Update
MAF arrived today. 1 minute to put the new one in. Nothing. Cranks, but won't start. Put the old CPS back in as a long shot that the new one died. No luck. Still won't run. Anyone have any suggestions? I've got to get it towed to the dealer and analyzed, I guess. These were there two suggestions, given the codes the car generated and the symptoms.
08-10-2010, 01:10 AM
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ML 320 - 2001
Problem solved
Turned out to be clogged fuel filter and a fuel pump with very low/intermittent pressure of 30 psi or less. I replaced those two things and she's been fine. But I did do the CPS and the air flow sensor. Getting 24 mpg again. Should do the spark plugs soon. I have 100K on those!
