M119 ETA questions

[guyonabuffalo]

Thanks, @gsxr I figured that was the case with the manual throttle cable messing around. I wont do it again.

Since the car has been driving fine, I decided to focus on the cooling system.

Based on just checking for resistance, the fan seems to resist movement - this seems to indicate that it is not busted. I dont see any leakage or other signs of wear on the fanclutch. I tried removing the bolt that holds it in place and no dice. I could not get it to budge. While there, I noticed that my belt is definitely due for replacement. So, maybe I will tackle that and do the thermostat at the same time. I wont mess with the fan clutch unless it is definitely confirmed bad. (Yes, I bought an aftermarket clutch )

Speaking of which - how in hell do I get to the bolt closest to the block? I lost a 10mm in the space behind the thermostat housing rubber elbow. While fishing for the 10mm with. magnet, I recovered a 13mm bolt. Since I couldnt get that back bolt off, I never managed to replace the thermostat.

** funny story - My last w140 was a 300SD and I replaced the intake and exhaust manifold gaskets on it due to leakage. While doing this job, one of the intake manifold bolts fell into the space between the block and the injection pump. I never found it. I think this bolt traveled through time and space to hide inside my S420. Which means that the next w140 I own will have a 10mm hidden somewhere in the engine bays crevices **

On other cooling system issues, how do I remove the big 4 pin sensor? The sensors next to it are so painfully close, I cant get a wrench or deep socket over it.




I will try to record the whirring sound I have been describing with a mic.

 

[gsxr]

You should be able to get a deep socket over the big 4 pin sensor - have you tried yet?

Yeah, the t-stat bolts are fun to access. If the 90° rubber hose is old, you might consider buying a new OE hose. It can be quite the challenge to get that on & off.

 

[emerydc8]

On other cooling system issues, how do I remove the big 4 pin sensor? The sensors next to it are so painfully close, I cant get a wrench or deep socket over it.

Use an O2 sensor socket. The part of the socket wall that is cut out will go towards the back between the sensor and intake manifold giving you enough room to break it loose.

 

[guyonabuffalo]

Hi folks, I managed to change 2 of the temp sensors (the large 4 pin and 2 pin next to it). The smallest single pin sensor connector wouldnt come off, I tried using a pick too to get it off but it seemed dead set on staying on or requiring me to force something and break the thing, so I left it alone. I have learnt from other posts about these sensors that the smallest one is for the gauge readout - since mine is working, I figured why not.

For anyone who is planning to replace their sensors - a thin walled deep socket did the trick. The O2 sensor socket wouldnt fit as the socket walls are too thick, which prevented the socket from sitting all the way down. My old sensors were likely original as they looked very brown and crusty.

Next move is to do the serpentine belt and hopefully the thermostat during that job.

So far, the ASR light has only come on once and that was after the car had sat outside for a while in the rain. I m still keeping my fingers crossed that the original ASR light and other weird issues were related to the car requiring a proper tune-up.

Thank you all for your help. I will continue to update this thread whenever something new happens.

 

[emerydc8]

Thanks for the follow-up. A thin-walled O2 sensor socket is what I used but it sounds like you got that one. On the frozen sensor, I agree that you can save yourself some aggravation—if it’s not broken don’t fix it

 

[guyonabuffalo]

Hi folks, wanted to fill you in on recent happenings. I have been driving the w140 pretty much daily for the past couple of months and it has been curious. The ABS and ASR lights came on a couple of times since my last post.

I would appreciate any knowledge anyone here can spare on how the fuel system works. Here is the back story

I recently replaced the original gas tank cap with a cheap aftermarket Gates cap - thinking that it would be better than my 31 year old cap. Turns out the cheap Gates cap is exactly that - $h!t. If anyone is in need of a gas cap, dont do it. Yesterday, but my son and wife complained of gas odors, followed by headaches (I was fine - but I also drive old diesels and enjoy a pint of engine oil now and then).
At this point, I noticed that the Gates cap felt really loose. I am used to the gas cap relieving pressure when opened after some driving. It did none of that. So, I went to the closest dealer and purchased the most expensive gas cap in my life for $126 CAD ($92 USD). This thing is beefy and has some heft. It also has an additional ring where the insert connects with the tank inlet.

Since putting the MB original gas cap on - the car seems to run better. Is it possible that the crappy Gates cap was not holding pressure in the tank and thus straining the pumps? If I understand the fuel system correctly, it goes -

1. gas in tank is kept under pressure but allowed to vent
2. pumps push fuel from tank, through filter into the fuel pressure regulator.
3. fuel arrives at the rails at a certain pressure.
4. so on and so forth....

Is this correct and if so, am I misunderstanding how the fuel is kept under pressure but also allowed to vent?

 

[TerryA]

@guyonabuffalo,
Try not to buy your parts from an MB Dealer Parts Department you will go broke. Buy parts online if possible.

You paid double for that gas cap. mbpartsource.com aka MB Lorado Texas lists the cap and a new sealing ring for $57.39 + whatever shipping to Canada.

Look up part under 94 S420 fuel tank and it will list all the components associated with the tank by number.

There is also mboemparts.com in Naperville, Indiana that sells online.

 

[emerydc8]

@guyonabuffalo,
Try not to buy your parts from an MB Dealer Parts Department you will go broke. Buy parts online if possible.

I hate buying parts from my dealer here in Tucson. Even if it's a $1 seal they'll charge five times more than I could get it for at Laredo just because they know they can. It's like they know I am there because I need the part now or the next day and they will punish me for it. I don't know who sets the pricing but it's just gouging. I guess there are some dealers who are not into selling parts unless they are installed by their techs.

 

[gsxr]

1. gas in tank is kept under pressure but allowed to vent
2. pumps push fuel from tank, through filter into the fuel pressure regulator.
3. fuel arrives at the rails at a certain pressure.
4. so on and so forth....

Is this correct and if so, am I misunderstanding how the fuel is kept under pressure but also allowed to vent?

That is all correct. In general, the fuel tank cap shouldn't affect engine operation.

 

[guyonabuffalo]

@TerryA Thanks for the advice. I have always bought parts online when I lived in Los Angeles - if I did ever need something urgently, BMA parts in Burbank had my back. Toronto however; is a parts desert in some regards. There are parts places everywhere but very little online presence and the places that will answer the phone will either need a long time to get something or cant get it at all. FWIW, $57 USD with Canadian tax, comes to about $83 CAD. I dont think I overpaid, since shipping and customs would have easily brought the price up to $120+ (CAD). I do agree that the word "stealership" is not unfounded.

@emerydc8 100%. They know they can, so they do it. I have used google translate to look for parts on European eBay pages and have ordered things from Lithuania and Germany. I have friends in both countries and they have helped me ship parts for very little money. If its small enough and declared for a small value - customs doesnt flag it for anything egregious.

@gsxr I thought so too but the difference in performance is baffling me. Its due for an oil change soon, I plan to do the belt, thermostat while I am there and maybe just the fuel filter. I was thinking of replacing the pumps but I cant be sure which pumps I am getting. There seem to be a lot of back and forth about the current Bosch pumps. I do have some aftermarket Chinese pumps that I have used on my buddys w124 in the past. They worked well and continue to do so. I have a couple of brands new ones on hand and was wondering if they would fare better than any shoddy (new) Bosch ones.

 

[gsxr]

I can't find where you posted the year/model of your car. I'm guessing a 1994 S420?

If your fuel pumps are original from 1993, it's good preventive maintenance to replace them. I wouldn't risk using Chinese pumps of any kind. Stick with Bosch, assuming you have the early dual-pump package (up to chassis A220200). After that break point a single Pierburg pump was used, with different mounting and different hoses.

 

[rayhennig]

Stick with Bosch, assuming you have the early dual-pump package

After recent Bosch misery I replaced the 2 pumps in my 300-24 with Pierburg equivalents. This despite having 2 Bosch pumps in stock.

No regrets a year later.

Oh and all MB original strainer, tubes, filter and accumulator (maybe that was Bosch) also.

RayH

 

[guyonabuffalo]

Hi folks, happy summer. My ASR and ABS light has been coming on consistently, these past few days.

I checked codes and got the following

Pin 19# Diagnostic Module:
6 - Idle Speed control inoperative
8 - Engine coolant temperature sensor open/short (I replaced this recently)

Pin 6# 3, 5, 26 - which are all related to VSS sensor

Pin 4# no codes.

Lately, that "whirring" when first starting to drive the car - that I so miserably tried to describe and catch on video - has been happening a lot more, sometimes while driving and as I am braking. It clearly affects the ABS system as I feel it under the brake pedal and when it happen during braking, braking performance feels weird for a second but then it stops and the brakes work just fine.

When the ASR/ABS lights come on at the same time, the brakes feel heavier/grips faster and steering feels heavier. I can verify that whatever is happening, removes steering assistance (most w140 cars have heavily assisted steering - too much, in my opinion) and possibly removes ABS as well.

Are M119 equipped cars known for having ABS issues/failures? The braking systems seem to be quite robust on both w124 and w140 models.

 

[gsxr]

DM codes are just telling you the throttle control system isn't working (ETA / E-GAS).

Any codes on pin #7 (E-GAS)?

ABS issues are not common. Have you inspected / cleaned the sensors that show up in the fault codes, and/or checked the wiring to them to confirm continuity from the sensor connector to the ABS module blade connector?

 

[guyonabuffalo]

Hi folks, sorry to keep reviving this thread but maybe some of what is discussed can be of help to someone.

My ASR/ABS lights have been pretty much ON the whole summer. It does not affect driving [my 1994 S420], other than make the steering heavier and brakes sharper.

This past weekend, as I was about to leave the shops, I started the car and heard a constant whirring - which sounded like the starter had stayed on. It was indeed the starter. I shut the car off but the starter wouldnt stop spinning. I panicked because I had no tools on me and couldnt disconnect the battery or really do anything. I did however pull one fuse at a time from the front fuse box. This did nothing but eventually the starter stopped spinning.
Anyway. After changing my pants, I started the car and it drove just fine. This time however; the ASR/ABS light hasnt come on since!

No idea what would have caused this, other than maybe pulling the fuses affected the ASR system?

Also, since my previous code readout had codes related to VSS, I tried taking them off to clean but the bolts but they are very rusty and wouldnt budge - so I sprayed some brake cleaner on and around the sensors and left it at that. I also purchased a heating coil that can be placed around nuts and bolts to heat them up without using a torch or other fire source and am hoping to try and use that to get those bolts off. Its hard to use a blow torch or other flame in that space because of various lines and bushings that are in close proximity.

 

[TerryA]

@guyonabuffalo,
In regards to your ASR/ABS lights pulling the fuses probably disturbed the corrosion between the fuses and connections. It’s a good idea to remove the fuses once in a while and make sure they make good contact. Always use brass fuses, don’t use aluminum fuses this automatically will cause corrosion.