What-ya think Alfonso - do you concure with LugNut ? Think I need to 're-program the ECU ?

 

First of all, keep one thread on this instead of plastering the same thing all over the place.

Second, don't try pitting me against sleepwalker or anyone else. We dont do that here.

Third, why did you disconnect the battery in the first place? What was it doing that prompted you to do that? Did you cause any shorts/sparks when you did it?

 

First off - I had no intention of this thing escalating and I tried to erase the 2 other threads but I do not have that privelage : perhaps you do ?

Secondly : I'm not "pitting" anyone against anyone : just looking for a second opinion : we could ALL use one of those !

Thirdly, and most importantly : As I already stated in the other thread I dis-connected the battery because I wanted to re-set the ECU since I had the feeling it was in "Safety Mode" ie : slow response and RPMs limited to about 4K, while all else was ok. No shorts or "sparks" I am not your "week-end" mechanic : I am a certified aircraft mechanic and I have done many ground-up restorations, including the 69 911E and the 1947 Cessna. My biggest handicap right now is not having the MBZ CD shop manual : I bought it and installed it but following a disk re-format lost it and am not able to re-install.

 

Well then, your impression of the problem is not quite right. You did not JUST disconnect the battery, and THEN your problems began. You disconnected the battery for a reason, therin lies your problem. I would GUESS that the disconnection exacerbated the underlying problem. Just a guess of the wild *** variety. Sorry I cannot help beyond this insight, if it is a help.

 

I would tend to agree with you C240AWD : I had a small problem (diminished performance) that I tried to rectify (by disconnecting the battery) and now I have a BIG problem and NO performance ! There is no doubt in my mind that disconnecting the battery prevoked the situation the question is how and what ?

 

Are you sure the car was in limp mode when you disconnected the battery the first time?

Are you sure the car is in limp mode now after the second disconnect and it's worse?

The reason I ask is because there is only one limp mode. There isn't a mild limp and severe limp. Either it was in limp mode or it is now, but not both times.

Unless something dawns on sleepwalker, I think it's time to take it to a shop for a diagnosis.

 

I think now what is a tow job followed by a ream job. Hurts double when you have extraordinary mechanical aility.

I think I would not tell Benz about the battery disconnect. Just tell them to fix it. Maybe you will get lucky and they will pinpoint the repair that needs to be done and you can take it away and do it yourself for a big savings. But it would have to be a real big savings. This is the sort of repair you want them to warantee.

It is time for the day whan the computer cars have built in diagnosticks.

Good luck. I for one would like to know how it turns out.

 

Let me re-cap the situation as objectivly as I can :

- 1998 C240T - V6 Sport Wagon with 5sp automatic transmission, 170,000KM total

- Over the last tank of gas (about 500KM) I noticed a small (+15%) increase in gas consumption; and rather poor performance reslulting in poor acceleration and the engine only making about 4K RPM max. All else OK except for very slight roughness in cold start and idle from time to time.

- Yesterday, I dis-connected the battery to see if that would have any effect on the performance issues.

- Immediatly after re-connecting the battery the car would start normaly , run 3 - 4 seconds then drop to slow/rough idle regardless of pedal position.

- I have removed and checked ECU unit to insure that it is proper up-dated version; I have checked fuel pressure at feul distribution ramp service valve - OK @ 3.5 bar; I have dis-connected the Air Mass Sensor and engine barely starts and dies immediatly - no "check engine" signal on dash.

I am VERY reluctant to bring to the Mercedes Stealership since a) the car will need to be flat-bedded there @ $400; b) The stelership will charge $200 for a "Fast Test" which normaly means conecting the StarDiag system and saying something like "gotta replace the thinga-ma-bob -that-l-be $1,899, ... but THEY WOULD NOT GIVE ME THE READ-OUT !!! ; c) My previous experience with the stealership has proven that they DO NOT analyse, but rather they apply the very expensive "shotgun" strategy of replacing system after system until problem disappears and generally leaving the owner (me) with a bunch of needlessly replaced parts and a BIG FAT repair bil....

I just wished I had my MIS "Mercedes Info System" shop manuals CDs to use for troubleshooting and I am VERY GREATFULL to yourself and especialy Alfonso for using his CD shop manual for me !

 

Oh, BTW : the shop rate at the Benz stealership here is, are you sitting down 'cause it's MORE than a jet mechanics' : ................... drum roll please.......... ONE HUNDRED AND TWENTY DOLLARS AN HOUR !

 

Maybe I'm picking up on too much detail, but did you say this started when you bought a certain tank of gas? Could the gas be bad? Happens a lot during winter. Mostly from moisture. Can you get some more gas in the tank and add some gas treatment that removes moisture? Could it be that simple? I dunno.

I don't like dealers either. Same reasons as you. I don't get the same nervous tics when I go to an independent shop. They have their reputation on the line and no large corporation backing them up and hiding their mistakes. They can't afford to lose customers by scaring them off with ridiculously high prices and the shotgun approach to auto repairs.