resistance for crank position sensor - Mercedes-Benz Forum
 
LinkBack Thread Tools Display Modes
#1 (permalink) Old 09-17-2003, 08:42 AM
BenzWorld Member
 
mike smith's Avatar
 
Date registered: Jul 2003
Vehicle: 98 slk 230
Location: Michigan
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
resistance for crank position sensor

Does anyone know what it should be? Mine is 1100 OHMs, which seems pretty high to me. I'm hoping that this $90 sensor is the source of my woes and my ticket to drive really fast past the MB dealer once I'm upand running again!

All input is greatly appreciated

99,000 miles and still like new.
mike smith is offline  
Sponsored Links
Advertisement
 
#2 (permalink) Old 09-17-2003, 03:16 PM
BenzWorld Elite
 
bgoin's Avatar
 
Date registered: Aug 2002
Vehicle: Classic 92 190E 2.6
Location: Neo-Nuremberg and Saint Mountain Meadows
Posts: 4,211
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 115 Post(s)
Re: resistance for crank position sensor

Quote:
Does anyone know what it should be? Mine is 1100 OHMs, which seems pretty high to me. I'm hoping that this $90 sensor is the source of my woes and my ticket to drive really fast past the MB dealer once I'm upand running again!

All input is greatly appreciated
Just what is the problem? The engine does not crank at all? If so there is a TBS, which applies: AF07.61-U-6000A, however it depends on the production date of the control module.

bgoin is offline  
#3 (permalink) Old 09-17-2003, 06:44 PM
BenzWorld Member
 
mike smith's Avatar
 
Date registered: Jul 2003
Vehicle: 98 slk 230
Location: Michigan
Posts: 90
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
bad stuff is happening


After posts to this forum and consultation with a few folks, here is the general summary. The car runs very, very rough and stalls and sometimes backfires. I toyed with the idea of a fuel delivery problem and replaced the filter, which was long overdue (I suspect) as the car has 80,000 miles on it. I have not checked the fuel pressure, but when I popped the pressure regulator, there was definitely pressure in the fuel rail. Plus, when the car runs, it reeks of unburned fuel. Conclusion = not a fuel delivery problem.

OBD II diagnostic connector pulls codes for misfires in cylinders 1 and 4. I thought maybe the 1/4 coil was bad so I swapped them - still miss on 1 and 4. OK...not likely a coil problem. Interestingly, I read today that the flywheel reference notches for the crank sensor are positioned at TDC for 1 and 4.


I replaced the plugs with Bosch +4's and had no luck. I tested spark with an in-line strobe, and all cylinders seemed to be firing well.

So....fuel and spark but almost can't even run....timing problem, I'm thinking.

Further, the O2 sensors were replaced in June and I just put in a new map sensor and air filter. I checked all the vacuum lines for leaks and ignition wires for shorts.

hmmm.....here is where I really began to think about visiting the MB dealer. Still hinking this has to be a timing problem of some sort, I checked the resistance of the crank sensor. It tested at 1100 OHMs. I heated it to 200 degrees F in my oven, and it then read 1200 OHMs. I made a quick visit to the used auto lot where I bought the car, and they were nice enough to let me hit another 98 slk they had on the lot with my multi meter. The crank sensor read 700 OHMs.

So my conclusion is that the crank sensor is sending exaggerated readings to the ECU (or whatever MB has to do that job) which is "advancing" the timing and causing this problem.

Is this conclusion worth gambling $100 of my pully upgrade budget....?

decisions, decisions..

but...the illuminated door sills look great....



99,000 miles and still like new.
mike smith is offline  
#4 (permalink) Old 09-18-2003, 04:25 AM
BenzWorld Extremist
 
DickB's Avatar
 
Date registered: Dec 2002
Vehicle: 1999 SLK 230
Location: Minnesota
Posts: 937
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Tough call.

The sensor is a coil; it is normal for the resistance to increase when the coil is heated. Hard to say if the difference in resistance between the two parts is significant. Can you get access to an oscilloscope? Parts departments don't generally accept returns of electrical items, but maybe you could make an arrangement with them.
DickB is offline  
Reply

  Mercedes-Benz Forum > Mercedes-Benz Roadster Forums > R170 SLK Class

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




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



Posting Rules  
You may post new threads
You may 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

 

Title goes here

close
video goes here
description goes here. Read Full Story
For the best viewing experience please update your browser to Google Chrome