ML320 po170 and 173 - Mercedes-Benz Forum
 
LinkBack Thread Tools Display Modes
#1 (permalink) Old 04-12-2008, 12:22 PM
BenzWorld Member
 
Date registered: Oct 2007
Vehicle: 2002 ML500 Silver
Location: SC PA
Posts: 74
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
ML320 po170 and 173

Yes, common errors. I keep getting these codes every few days after reseting.

I have just:
Replaced Air Filter
Replaced spark plugs...had 100k on the last set.
Replaced MAF

Perfect idle, great gas mileage, starts every time easily...I do use midgrade gas, should I use premium? I have not used premium for years.

What is next fuel pressure regulator?

Any help is appreciated.

1998 ML320 185k miles.

Thanks,
Ed

Last edited by Pinballer; 04-12-2008 at 12:24 PM.
Pinballer is offline  
Sponsored Links
Advertisement
 
#2 (permalink) Old 04-12-2008, 12:58 PM
BenzWorld Elite
 
Date registered: Aug 2006
Vehicle: 02 ML320
Location: Bronx, New York
Posts: 10,675
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 36 Post(s)
Quote:
Originally Posted by Pinballer View Post
Yes, common errors. I keep getting these codes every few days after reseting.

I have just:
Replaced Air Filter
Replaced spark plugs...had 100k on the last set.
Replaced MAF

Perfect idle, great gas mileage, starts every time easily...I do use midgrade gas, should I use premium? I have not used premium for years.

What is next fuel pressure regulator?

Any help is appreciated.

1998 ML320 185k miles.

Thanks,
Ed
Code 170 and 173 usually always relate to the MAF sensor, but you said that you have replaced it. My question is WHAT BRAND MAKE IS IT & WHERE DID YOU PURCHASE IT FROM/
43sqd is offline  
#3 (permalink) Old 04-14-2008, 08:14 PM
BenzWorld Member
 
Date registered: Oct 2007
Vehicle: 2002 ML500 Silver
Location: SC PA
Posts: 74
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
I am on my third MAF. Current MAF is Bosch. I have the old Bosch I replaced at 79k, a new aftermarket one, and known good from co-workers ML that threw the codes before I got out of the parking lot. My old one goes 2-3 days and the new one went 4 days before the check engine light. Happens while at speed, or at idle.

Could this be my K&N filter? It has been in the car since 90k with no problems ( I clean and lightly oil every 6 months). I may try a stock filter and premimum gasoline for awhile. I have a yearly vehicle inspection due this month and would like to pass it...and take care of it for the long run.
Pinballer is offline  
#4 (permalink) Old 04-15-2008, 02:01 AM
BenzWorld Elite
 
Date registered: Aug 2006
Vehicle: 02 ML320
Location: Bronx, New York
Posts: 10,675
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 36 Post(s)
Quote:
Originally Posted by Pinballer View Post
I am on my third MAF. Current MAF is Bosch. I have the old Bosch I replaced at 79k, a new aftermarket one, and known good from co-workers ML that threw the codes before I got out of the parking lot. My old one goes 2-3 days and the new one went 4 days before the check engine light. Happens while at speed, or at idle.

Could this be my K&N filter? It has been in the car since 90k with no problems ( I clean and lightly oil every 6 months). I may try a stock filter and premimum gasoline for awhile. I have a yearly vehicle inspection due this month and would like to pass it...and take care of it for the long run.
Please take a minute to update your profile and include the year and model of your truck.

I'm assuming that you have had the codes read and that there are no additional codes besides the 170 & 173.

These two codes signify that there is lean condition, meaning that there is too much air going in for the amount of fuel, so the computer increases the amount of fuel to compensate for the added air.

You will have to inspect the upper portion of the engine and look and listen for any possible vacuum leaks. Look for broken, brittle or soft hoses.
43sqd is offline  
#5 (permalink) Old 04-15-2008, 05:16 PM
BenzWorld Member
 
Date registered: Oct 2007
Vehicle: 2002 ML500 Silver
Location: SC PA
Posts: 74
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Thank you for the information.
I have just inspected the air hoses and all appear to be supple enough and connected properly.

I am going to try a stock airfilter. I may have under-oiled my old K&N and it may be flowing a little too good.

I will post the results.

Ed
Pinballer is offline  
#6 (permalink) Old 04-15-2008, 07:35 PM
BenzWorld Elite
 
Date registered: Aug 2002
Vehicle: Black 2005 ML 500
Location: Galveston, TX
Posts: 1,662
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
ML320 po170 and 173

Isn't a lean condition when there is too little fuel getting into the engine? Maybe caused by a potential vacuum leak that reduces the air flow through the MAF sensor, and therefore, the computer does not feed enough fuel to the engine causing it to miss..? Maybe my understanding is a little bit simplistic..?

AC

Quote:
Originally Posted by 43sqd View Post
Please take a minute to update your profile and include the year and model of your truck.

I'm assuming that you have had the codes read and that there are no additional codes besides the 170 & 173.

These two codes signify that there is lean condition, meaning that there is too much air going in for the amount of fuel, so the computer increases the amount of fuel to compensate for the added air.

You will have to inspect the upper portion of the engine and look and listen for any possible vacuum leaks. Look for broken, brittle or soft hoses.

2005 ML 500
Black, 18" AMG Wheels, 285/60R18 Yokohama Geolander HTS + Bi-Xenons(+ Drew's e-code mod, though the reflectors rusted off and do not give out much light anymore), Yakima roof bars, Akebono pads all around. Former vehicle 2001 ML 320 with 108K miles, when traded, and a large repair/defect history. After all these years of owning my current 2005 ML 500, it is a major unreliable vehicle with a very large/expensive repair/defect history and has been like this since brand new.
AC_ML is offline  
#7 (permalink) Old 04-15-2008, 07:46 PM
BenzWorld Member
 
Date registered: Oct 2007
Vehicle: 2002 ML500 Silver
Location: SC PA
Posts: 74
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Not necessarily make it miss but still may be lean enough for the ECU to think the MAF is bad is the idea that I am getting from 43sqd.
At worst, a lean condition for too long could harm the pistons. In my case, the spark plugs that I pulled out after 100k miles (and a 25k with the light on), had a nice color and no indication that the car was really running too lean. It is my understanding that if the mixture is out of a certain range, it will throw a code.

I am going to revert back to a stock air filter...they are like 3 inches think and the K&N is very thin and free flowing. I am hoping that this restriction will make the ECU happy and keep the light off.

The car still runs and feels like it did at 76,000 miles. I am very pleased with it. I hope to get at least 250k out of it before I have to make any major repairs.
Pinballer is offline  
#8 (permalink) Old 04-15-2008, 08:29 PM
BenzWorld Elite
 
Date registered: Aug 2006
Vehicle: 02 ML320
Location: Bronx, New York
Posts: 10,675
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 36 Post(s)
Quote:
Originally Posted by AC_ML View Post
Isn't a lean condition when there is too little fuel getting into the engine? Maybe caused by a potential vacuum leak that reduces the air flow through the MAF sensor, and therefore, the computer does not feed enough fuel to the engine causing it to miss..? Maybe my understanding is a little bit simplistic..?

AC
No AC. Running lean means that too much air is being entered into the combustion chamber for the correct amount of fuel. Whenever there is a broken vacuum hose or leak at the intake manifold, more air is being suck in than is required because the crack in the hose is also sucking in outside air along with the usual vacuum.. The O2 sensors sense this "too much air" reading and they tell the computer to keep the injectors open a little longer, adding more gas to compensate for the added air. Running lean could also mean that you have the correct amount of air entering, but you are not getting the correct amount of gas. But as we know, 170 and 173 are always set because of air readings.

Conversely, a rich condition is attributed to too much fuel entering for the correct amount of air. Therefore there is no way that the computer can add air to the overload of fuel, so it would have to command the injectors to stay open for a shorter duration than what is normal.

Although it is a little confusing, I hope I have covered everything..


Running Lean-too much air for the correct amount of fuel........80%...or
-too little fuel for the correct amount of air..........20%


Running Rich-too much fuel for the correct amount of air 50%
-too little air for the correct amount of fuel 50%
43sqd is offline  
Reply

  Mercedes-Benz Forum > Mercedes-Benz Vans/Trucks/SUV/Others > W163 M-Class


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Topic Author Forum Replies Last Post
Error codes PO170 & PO173 - ? Dadaman General Mercedes-Benz 8 04-22-2011 01:27 PM
codes PO173, PO170 & PO446 kwiklee W163 M-Class 2 08-13-2007 07:08 PM
Please help w/ OBD 161, 173 codes mslc791 W163 M-Class 3 06-01-2007 02:21 PM
Pollen Season = CEL = PO170 & PO173 Codes CCORLEY W163 M-Class 1 05-16-2005 09:59 AM
Pollen Season = CEL = PO170 & PO173 Codes CCORLEY W163 M-Class 1 05-15-2005 06:46 AM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome