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Hello All,

Well, my 16 year old son has gotten the Merc bug - he just purchased a non-running W140 as a project car. He's driving my old W124 e420 now, so he's familiar with the M119 since we just went thru it on the e420 to pass CA smog. This W140 500SEL is ridiculously clean (in, out, and under the hood) and un-hacked up (Northern CA Car.) Apparently had some misfiring and other issues when it last ran in (cough) 2012.

So we're trying to get the fuel system purged out just to see what we've got to work with. We realize we could be in for cleaning the tank and more, but we just want to get new fuel flowing to see where we are.

We pulled the in and out lines off of the fuel rail, and ran the fuel pump with the key (that few seconds of run time when you go to "on") and we get fuel for a couple of seconds, and then it barely dribbles. We re-key again, and hear the pump(s) run, but fuel barely comes out.

We replaced the fuel filter, and gave it another try, same effect. We're going to start at the input to the pumps, and see if fuel is flowing through both pumps (and if they are both working.)

Does anyone have a fuel diagram for the car?[/U][/I] We'd love to be 100% sure the order of flow through the pumps and the filters. It appears that it goes Tank-> Upper Pump -> Lower Pump -> Filter -> Fuel Rail. We'd also like to fully know which is the "in" connection and the "out" connection on the rail (in other words, is the regulator on the IN, or on the RETURN?

Thanks in advance. Will be nice to get this decent example of a bygone era of engineering on the road. Gotta love when your 16 year old thinks this is "cool" :)

~Bryan
p.s. photo of car attached.
 

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Hello All,

Well, my 16 year old son has gotten the Merc bug - he just purchased a non-running W140 as a project car. He's driving my old W124 e420 now, so he's familiar with the M119 since we just went thru it on the e420 to pass CA smog. This W140 500SEL is ridiculously clean (in, out, and under the hood) and un-hacked up (Northern CA Car.) Apparently had some misfiring and other issues when it last ran in (cough) 2012.

So we're trying to get the fuel system purged out just to see what we've got to work with. We realize we could be in for cleaning the tank and more, but we just want to get new fuel flowing to see where we are.

We pulled the in and out lines off of the fuel rail, and ran the fuel pump with the key (that few seconds of run time when you go to "on") and we get fuel for a couple of seconds, and then it barely dribbles. We re-key again, and hear the pump(s) run, but fuel barely comes out.

We replaced the fuel filter, and gave it another try, same effect. We're going to start at the input to the pumps, and see if fuel is flowing through both pumps (and if they are both working.)

Does anyone have a fuel diagram for the car?[/U][/I] We'd love to be 100% sure the order of flow through the pumps and the filters. It appears that it goes Tank-> Upper Pump -> Lower Pump -> Filter -> Fuel Rail. We'd also like to fully know which is the "in" connection and the "out" connection on the rail (in other words, is the regulator on the IN, or on the RETURN?

Thanks in advance. Will be nice to get this decent example of a bygone era of engineering on the road. Gotta love when your 16 year old thinks this is "cool" :)

~Bryan
p.s. photo of car attached.
Have you checked/changed the pre-filter in the tank? Sitting that long, it could be plugged with crud. If it is, you'll probably need to pull the tank and have it flushed. To remove that filter, you have to remove the fuel feed hose coming from the tank, and then remove the fitting from the bottom of the tank. The filter is attached to that fitting. You'll need a new seal if you remove it. Replacements from MB should come with the seal.

When you tried to pump fuel, did you loosen the gas cap. If the vent system is plugged, you could be drawing a vacuum in the tank, limiting fuel flow.

The fuel from the back directly enters the fuel rail. The regulator is at the exit of the rail.

The feed hose goes directly to the pumps from the tank, then through the canister fuel filter before going to the engine.
 

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Thanks @GreenT and @jal1224 - that site was super helpful (better than the Alldata that we have now.) And we were wondering about some sort of pre-screen. We were planning to drain the tank tomorrow, so we'll have a chance to inspect the screen and see what kind of condition the tank might be in. We're going to pull the pump pack out and go over it as well (we've got a new fuel filter already.)

Thanks for all of the help, looking forward to getting the old girl on the road again. I'm sure there will be more gremlins to chase down the road, but that's part of the fun.

Thanks again!
 

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hi,

can anyone help with a wiring harness diagram, got a w140 V8 m119 1992 in the UK - bought it as 1 own car but hasnt run right for the last 2yrs!

it has burnt two air masses cost alot of money and we think it maybe a wiring issue, or some sort of voltage spike.

can anyone help? it just doesnt run right - and its such a nice car its a shame we cant use it properly.

any help would be great, if anyone has a pdf of this or a haynes manual.

any help would be great

thanks

Jay
 

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hi,

can anyone help with a wiring harness diagram, got a w140 V8 m119 1992 in the UK - bought it as 1 own car but hasnt run right for the last 2yrs!

it has burnt two air masses cost alot of money and we think it maybe a wiring issue, or some sort of voltage spike.

can anyone help? it just doesnt run right - and its such a nice car its a shame we cant use it properly.

any help would be great, if anyone has a pdf of this or a haynes manual.

any help would be great

thanks

Jay
Welcome to the forum.

You may have the "biodegradable" wiring harness issue that affected all W140s until the 95-96 time frame. Look for a white Delphi tag somewhere near the connector where the engine harness plugs into the rest of the wiring. If you have that, your harness has been replaced already. If you don't find that tag, carefully cut a lengthwise slit in the sheathing over the wires to the MAF. Examine the insulation of the wires there. If it is bright, shiny, and flexible, you are good. If it is cracked, crumbling and dull looking, you need a new harness. They are commonly available used, at least in the US, such as this example:

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/332900361101

Please note that since your car is RHD, that exact harness likely won't fit.

There are no aftermarket manuals for the W140. There is a download available of a limited repair manual in the manual portion of the DIY section of the stickies, here, post #203:

https://r.tapatalk.com/shareLink?url=https://www.benzworld.org/forums/showthread.php?t=1636494&share_tid=1636494&share_fid=13657&share_type=t

It has the wiring diagrams. It works best under Windows XP, but can be made to work under Windows 10. There is info on what to do to get to all the data earlier in the thread.

Also look at post #206 in that thread. I summarize what is available in terms of workshop manuals. There used to be online access to the wiring diagrams, but that site died a few months ago.

In the future, please start a new thread, as it won't get mixed up in someone else's thread.

Jon
 

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hi Jon,

really appreciate your response on this.

yes we have had the wiring harness done with all new wires but we are not confident that the wires in the maf plug have been put back the right way round e.g on the maf plug where does pin 1 link to in the ECU plug what pin? Maf plug pin = ecu pin 4?

this is what we need to confirm - its annoying to buy a maf and it to burnt out in 2secs of the car being on and being back to square, so hopefully i can get some information on the link you have sent relating to this.

we have changed all of the below

Plugs
lead
distro caps and rotors
both crank sensors
2 new fuel pump
fuel filter
temp sensor
1 of the ECU thats slots in to the main box
ignition module

and alot more that i cant remember

apologies for posting here but was unable to start a new thread.

can you recommend who would refurb the MAF?

its impossible to get one from Bosch now as they are on a back order for ages.

thanks again
 

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Here is the wiring diagram and legend for the 1992 M119 engine.

I checked various sources for the MAF sensor, but didn't have much luck. Hopefully, someone else pipes up with one.

Jon
 

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Discussion Starter #11
Hello All,

Wanted to just circle back to all who were a part of this thread when I started it in October of last year.
My son's car project is on the road, and it's his daily driver! I'm pretty stoked that my 17 year old thinks a 27 year old S-Class is a cool ride!

He put a lot of work into getting this car going. One of the fuel pumps was in fact bad, but that wasn't the problem at all - after going through just about everything (previous owner threw parts at it like crazy, harness, caps/rotors/plugs, cam sensor, etc) we took the valve covers off to check cam timing, and sure enough, in addition to the chain guides being mostly disintegrated, we found the chain very loose, and timing was off by a very stable amount.

After compression check, we were pretty confident that there were no bent valves, he saved up his money, bought the cam chain and guides, new tensioner, etc. In and around his active church and social life, we managed to get it all put back together a couple of months ago. We cranked it for a while with no plugs to get oil pressure up, then started right up, had a nasty lazy lifter after sitting for 7 years, but after it warmed up, she was a runner.

He drove it without AC for about a month, then we raided a few Pick-N-Pull cars and got a good blower motor. Changed that out last week, charged it up and AC blows ice cold.

Still a few things to work out, clunky sound in the rear going over bumps (I'm sure some bushing is dried out,) drier window regulator is binding, no stereo ( first generation Bose amp circuit board and capacitors are toast) and the odometer is frozen (pretty certain dried out capacitors in the dash module.) But he's very proud of his $1200 investment, plus about another $1200 in parts including tires, and a plethora of pick and pull runs. He's started grabbing pre-'93 M119 cam oilers, running them through our ultrasonic washer, and selling them on e-bay to buy parts. I think this weekend he's doing pads and rotors, and bearings in front.

Thanks to all who chimed in. Here's a few pictures, including the first crank after the cam chain install, and the first start video.

~Bryan

https://www.icloud.com/sharedalbum/#B12GqkRUiGPynE5
 

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Still a few things to work out, clunky sound in the rear going over bumps (I'm sure some bushing is dried out,) drier window regulator is binding, no stereo ( first generation Bose amp circuit board and capacitors are toast) and the odometer is frozen (pretty certain dried out capacitors in the dash module.) But he's very proud of his $1200 investment, plus about another $1200 in parts including tires, and a plethora of pick and pull runs. He's started grabbing pre-'93 M119 cam oilers, running them through our ultrasonic washer, and selling them on e-bay to buy parts. I think this weekend he's doing pads and rotors, and bearings in front.

Thanks to all who chimed in. Here's a few pictures, including the first crank after the cam chain install, and the first start video.

~Bryan

https://www.icloud.com/sharedalbum/#B12GqkRUiGPynE5
Yea, these 500's/600's can have this nagging issue of suspension:

For starters, you need to replace your accumulators and hydraulic fluid before anything else, but the hydraulic ram(the shock...) can have bad bushings too.

Excellent thread-Post 16 also how to flush the system out...

https://www.benzworld.org/forums/w140-s-class/1697808-please-someone-help-me-theyre-killing.html

Bushing fix on a non service part:

https://www.benzworld.org/forums/w140-s-class/2635090-my-solution-replacement-lower-sls-joint.html

This fails on these cars too:

The inner one is not so bad:

https://www.benzworld.org/forums/w140-s-class/2130721-photo-diy-rear-lca-inner-bushing.html

The outer one looks awful on most W140's

https://www.benzworld.org/forums/w140-s-class/2116922-photo-diy-rear-lower-control-arm.html

On your radio, The 92/93 cars have a very preparatory radio that is NOT up-gradable as the wiring is not conducive to just adding "another stereo".

A) Keep finding 92/93 cars and buying Amp's and Tuners. Working the PickNpull 30day warranty until you find one which will be really rare as capacitors die like a gallon a milk does-It makes no difference how many miles on the car-they spoil, and go bad. You get an "E2" error on the head-unit. It is two things 1) the cable to the tuner has a open line 2) the communication side of the tuner has bad capacitors in that section.

B) You can fixit... it takes me like 40 to 50 hours on those old units to do all three units(Tuner, Amp, & Head Unit)

https://www.benzworld.org/forums/w140-s-class/1705705-w140-bose-amp-bench-testing.html

C) My buddy did this to one of his 500SEL. On one of those 50% off days at Pick-N-Pull he pulled the Radio, Amp, Antenna, Amp mounting bracket, and ALL the audio wiring from the head unit to the amp, and the wiring from the amp to the door connectors plus the woofer wiring too. The Antenna is different from +94 as they have a color outside cone that matches the paint, and the 92/93's do not.. It is challenge to get all of it out. It took him two or three days, and the install took four days as the seats have to come out. The carpeting has to fold back around the seats. The +94 cars sound way better than the 92/93 cars, and the +96 cars have a bit more bass as the amp was redesigned. The amp on the later cars are more likely to work from the junk yard. You can do that, but these stock audio system on the later sound great- very well balanced...


The instrument cluster capacitors are easy to change out it is like 4 or 5 of them, and you got Fry's Electronics, and HSC Electronics, but I would always do that first on those old clusters. R129's(The SL's) with the Analog odometers have this chronic problem, but on a SL if the cluster does not work correctly. The soft top controller will not get the processed speed signal, so different problem there...

Best of luck,

Martin
 

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Hello All,

Wanted to just circle back to all who were a part of this thread when I started it in October of last year.
My son's car project is on the road, and it's his daily driver! I'm pretty stoked that my 17 year old thinks a 27 year old S-Class is a cool ride!

He put a lot of work into getting this car going. One of the fuel pumps was in fact bad, but that wasn't the problem at all - after going through just about everything (previous owner threw parts at it like crazy, harness, caps/rotors/plugs, cam sensor, etc) we took the valve covers off to check cam timing, and sure enough, in addition to the chain guides being mostly disintegrated, we found the chain very loose, and timing was off by a very stable amount.

After compression check, we were pretty confident that there were no bent valves, he saved up his money, bought the cam chain and guides, new tensioner, etc. In and around his active church and social life, we managed to get it all put back together a couple of months ago. We cranked it for a while with no plugs to get oil pressure up, then started right up, had a nasty lazy lifter after sitting for 7 years, but after it warmed up, she was a runner.

He drove it without AC for about a month, then we raided a few Pick-N-Pull cars and got a good blower motor. Changed that out last week, charged it up and AC blows ice cold.

Still a few things to work out, clunky sound in the rear going over bumps (I'm sure some bushing is dried out,) drier window regulator is binding, no stereo ( first generation Bose amp circuit board and capacitors are toast) and the odometer is frozen (pretty certain dried out capacitors in the dash module.) But he's very proud of his $1200 investment, plus about another $1200 in parts including tires, and a plethora of pick and pull runs. He's started grabbing pre-'93 M119 cam oilers, running them through our ultrasonic washer, and selling them on e-bay to buy parts. I think this weekend he's doing pads and rotors, and bearings in front.

Thanks to all who chimed in. Here's a few pictures, including the first crank after the cam chain install, and the first start video.

~Bryan

https://www.icloud.com/sharedalbum/#B12GqkRUiGPynE5
Tell your son for me, he is absolutely correct a 27 year old S-Class is a cool ride! Also let him know that he has skills because he knows how to drive. No autopolite, lane assist, break assist, auto parking for him. He'll know his limitations and probably not get into driving situations that he can't handle. He also has protection around him from other drivers get to close, trying to look at how cool his ride is.:thumbsup:
 
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