MAF and Transmission Connection!!

Greetings,

Its a happy day for 2 reasons, first because my car now runs great and secondly because I get to give back to the group that has been so helpful to so many.

My 95 S320 started acting up a few months ago with a hunting and unstable idle both in park and in gear. I tried fuel injector cleaner, plugs, etc and no change. Then about a month ago I lost 5th gear. The mechanics said I needed a tranny rebuild (around 90K miles) so I scheduled an appointment.

Last week I borrowed a friend's scanguage tool to check the rough idle and the error codes pointed to MAF (P0101 and P0170). I tried cleaning it but no luck.

Today I installed a new MAF and idle immediately improved. I took her out on the highway for an "Italian tune-up" and to my surprise I regained 5th gear and it shifts perfectly upon acceleration and back to 5th as it should.

Needless to say I canceled the appointment for the tranny rebuild.

Hope that helps someone, Bob

Reply to
Bob
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That's great to hear Bob. Congrats! Did you use OBD2 scanner to pull that code? Do you remember what brand it was and model if possible? I am just curious.

Reply to
Tiger

The tool I used is called ScanguageII manufactured by Linear Logic. I just bought one for myself. It is very cool, shows many parameters the ECU sees while you drive such as ignition settings, intake air temp, coolant temp, O2 sensor loop open/close, etc.

It also shows codes, clears codes and shuts off the "Check Engine Light". If that wasn't enough it also has a very cool trip computer built in for MPG (or liters) avg speed, max speed, range, etc.

Plugs into OBD2 plug under dash so it's easy to move car to car. Check it out at

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I'm in no way affiliatedwith them, just very impressed with their product. Bob

95 S320

Reply to
Bob

Hey Bob, I took a look at that tool... seems a simple tool. For average joe, it probably is enough. Personally I'd rather buy AutoXray than that... doesn't cost much more either and you can fix almost every car in USA from 81 and up. Free software update... which is very rare for any OBD2 handheld manufacturers.

Another company I like for strictly 1996 or newer OBD2 scanner to be used on laptop or Palm... is

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Their tool is much more informative and interactive... cost just the same as that tool you just bought. I think the laptop one is much more useful. I have used the Palm as I did set up one for my friend and borrowed his kit sometime. Palm is small and useful but laptop will give you more in depth information than Palm can give you... but laptop is not that portable... which I can deal with.

The current scanner I have is Carsoft for Mercedes only... I still have alot to learn on how to use this tool... it is way harder to use and no where near the Auterra stuff... but Carsoft does access other part of car whereas Auterra cannot access...

I think I will also buy the Auterra laptop kit so I have complete diagnostic setup for personal use...

Reply to
Tiger

Hi Tiger, Thanks for the links, intersting stuff. The Scangauge is, as you say, more for the avereage Joe (like me). I really like the trip computer since my car didn't come with that option. I see it is limited in it's areas of diagnosis when compared to the others you list. With the Auterra laptop kit added to your toolbox I think you'll be able to see anything the MB tech could find!

I think I speak for many in this group by saying, "Tiger, we are glad you are not an average joe"!! I really appreciate the input from you and the others in this group. Thanks, Bob

Reply to
Bob

Hello I saw your post. I have a 95 SL320 with the same 5 speed trans. It is hard to tell whether it is going into fourth or fifth. I am curious about the following

  1. When you are cruising in fifth what engine RPM are you running at? At
80mph mine indicates 3000rpm.
  1. I do not seem to get a solid converter lockup at cruising speed. At least not as noticeable as on my 190E. Taking the foot off the pedal and reapplying throttle shows a variation of about 300 rpm
  2. When in top gear and full throttle I do not get an immediate downshift. There is a lengthy lag and it seems to skip a gear to the next lower ratio with a substantial corresponding increase in RPM.

Fluid and filter was changed 20k miles ago, current odo is 106k. Car runs fine shifts smooth etc.

Any thoughts / input re. the above will be appreciated

Peter

Reply to
Peter W. Peternouschek

If you have OBD2 connector, hook it up and see what code it spits out. It probably is your MAF.

Reply to
Tiger

Hi Peter,

I just got back in town and saw your message. Yes my car behaves as you describe in the comments 2, and 3. As for RPM in fifth it indicates 2000 RPM at 60 MPH

Reply to
Bob

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