News:

The ORG - Truly Independent and Unbiased!

Main Menu

280se - new to me, warm stalling!

Started by SteveDuNord, 04 May 2022, 10:57 AM

SteveDuNord

Had my garage door fixed today which meant I could drag the 3 tonne jack straight to the car. So I decided to tackle the fuel filter after all.

I read up on jacking points (thank you w116 forum archive) and cracked on with the fuel filter change. Well, removal...

jacked:



The crusty cradle was a pain. Fortunately I had a long 8mm (I think) socket, and popped a spanner on the nut situated on the other side. Fiddly.



Unfortunately the filter to pump hose nut was welded on, making it impossible to unscrew the other end of the filter from its hose. At this point I'm cursing the car again!



Eureka moment as I realised there was enough slack to pull the filter out of the cradle and screw away. Phew. Filter is dated 2019 as per service records. Unlikely to be the cause of my fuel delivery problem but hey ho.




Once dangling I could slip the hose off. A good feeling.

The nut was rounded off, making spanners useless, luckily I had another long socket that was willing to bite.

But still, how to apply enough torque for removal? That's right: stripy socks and a mallet.



Now I'm really delighted. All that's left is the screw the nut back into the filter and replace.

But no, the thread in the old filter was butchered. they'd added some sort of thread lock to stop it leaking. It will not mate with the new filter.  >:(



So I'm thinking either
a) the filter is wrong. (The old one is the same as the one I ordered. Mahle KL- 19).

b) The nut/fitting is wrong:



Thoughts?

I've seen other Mercs use a banjo fitting on the fuel pump end and filter end both. Maybe this part was never the right one??







'77 280se

johnnyw116

#91
yes that nut fitting is wrong and they also butchered the banjo hose , so you need an new banjo hose between pump and filter , and you also need the hollow banjo bolt for fitting the new banjo hose on the fuel filter an four 12x16 washers , i checked at niemoeler the part numbers the fuel hose you need is part number: 123 470 06 and the banjo bolt has part number :915036008202 but according to niemoeler this part is NLA maybe the bolt has an new part number ? but on google i checked this 915036008202 and i saw this banjo bolt also on autodoc
JohnnyW116
350SE 1974 861H
200D   1981 737H "Taxi"

SteveDuNord

#92
Quote from: johnnyw116 on 29 July 2022, 07:42 PMyes that nut fitting is wrong and they also butchered the banjo hose , so you need an new banjo hose between pump and filter , and you also need the hollow banjo bolt for fitting the new banjo hose on the fuel filter an four 12x16 washers , i checked at niemoeler the part numbers the fuel hose you need is part number: 123 470 06 and the banjo bolt has part number :915036008202 but according to niemoeler this part is NLA maybe the bolt has an new part number ? but on google i checked this 915036008202 and i saw this banjo bolt also on autodoc

Thanks very much.

I found this hose last night and think it might be the one I need?
https://parts.theslshop.com/mercedes-benz-sl-r107-w116-w123-pump-filter-fuel-line-1234700675/

And if the bolts are m12 I wonder if these would be compatible?

https://www.amazon.co.uk/AUTOHAUX-Diameter-Banjo-Washer-Motorcycle/dp/B088QLPZSB/ref=asc_df_B088QLPZSB/?tag=googshopuk-21&linkCode=df0&hvadid=500890667741&hvpos=&hvnetw=g&hvrand=16399782015867408704&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=1007282&hvtargid=pla-1380214669152&psc=1

These are the only UK based solutions I've found so far.
Edit: probably a better idea to get the banjo bolts shipped from Autodoc! At least I know they'll be compatible.
'77 280se

johnnyw116

#93
Yes that is the hose you need , i seem to have lost the last two numbers when i was copying the partnummer 123 470 06 75 , and that bolt size is M12x1.50 , you can also order that hose at the local MB dealership and i think it is about the same price there and maybe they can also help you out with that banjo bolt
JohnnyW116
350SE 1974 861H
200D   1981 737H "Taxi"

SteveDuNord

#94
Quote from: johnnyw116 on 30 July 2022, 04:21 AMYes that is the hose you need , i seem to have lost the last two numbers when i was copying the partnummer 123 470 06 75 , and that bolt size is M12x1.50 , you can also order that hose at the local MB dealership and i think it is about the same price there and maybe they can also help you out with that banjo bolt

Good idea, will ring them on Monday.  8)

Managed to get them ordered in. The hose was around the same price as SL shop and the banjo bolts were £13 each - the guy found a part number that had superseded the the 9150 number. I bought two, might as well replace the pump bolt while I'm there. Can pick them up on wednesday so that's much more convenient.
'77 280se

s class

Those fuel filters have a specific flow direction indicated by an arrow, and it looks to me like that old one was installed backwards


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

SteveDuNord

#96
Quote from: s class on 07 August 2022, 01:05 PMThose fuel filters have a specific flow direction indicated by an arrow, and it looks to me like that old one was installed backwards

I think that might be because of my photos?

One end is an olive (?) nut connection and the other is for a banjo bolt, so I'm not sure you can go wrong.

Meanwhile, I collected the correct banjo bolt from Mercedes, but it didn't come with any copper washers. I bought some from an autoparts shop, but apparently they can leak because they are much harder than the ones Mercedes use.

I tightened the hell out of it using a 17mm spanner on the opposite end for grip:



Here is my shiny new hose installed. It weeps just a tiny amount from the banjo bolt, so I'll order some OEM washers.



Did another pressure test - no change. 5 bar system and control pressure. But at least I have a new filter on... I will check the flow tomorrow but imagine it will still be below spec. Maybe a new fuel pump is required.

I also received my new fuel distributor inlet filter. The old one - which has a metal gauze strainer bud - is shorter, but the fitting is correct.

Good job I bought extra washers because it also came without any.



Problem - the engine started knocking and spluttering on startup. (ignore! Throttle linkage was caught on fuel line)

I wondered whether the new FD filter had fixed a flow issue, which might have caused a super rich mixture setting.
I tried to adjust the mixture screw (3mm allen) but the wrench wouldn't bite. Just kept turning around.
(Doh - was using a 2.5mm allen wrench) :D

'77 280se

SteveDuNord

#97
Well I finally  got time to fit a new fuel pump courtesy of the good people at Bosch.

Covered myself in litres of fuel until I realised where to clamp the fuel hose. ;D



And wouldn't you know it? The fitting is too small for the hose, here's the new and old pumps alongside each other. I'm pretty sure they're both Bosch but the size/shape is different.



The instructions for the pump show two different sized screw in fuel hose connectors, one larger than the other. Mine only came with the smaller one.

I bought BOSCH 0 580 464 202

https://www.autodoc.co.uk/bosch/17008003

It's possible that the old pump was ordered incorrectly, a late 1977 version, whereas my car is early 77. Records show that the mechanic also made up new fuel lines. Maybe he chose a hose that matched the pump he had ordered? We've already discovered that he butchered the fitting for the filter!

 I should have measured the fuel damper connector diameter while the wheel was off. They also come in different sizes. Gah! New hose and try again.
'77 280se

raueda1

I just went through the exact same stuff.  It seems that all the components stuff back there went through changes in fittings over the years so there's no single answer. I got my fuel pump from Classic Center - a little more expensive but better confidence that it would be right.  It came with a bunch of fittings to make it work, which it did. At the end of the day you just need to cobble together the fittings that are needed.  Keep an eye on that hose.  Mine failed in just 3 years!

Also, you actually CAN reuse copper washers.  Just heat until brightly glowing with a torch and quench in water. They'll be soft again and good as new unless severely damaged.  Cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

SteveDuNord

Here's a pic from the pump instructions.

Mine is in the middle. If you have the banjo bolt on one end, you're meant to have a 12mm fitting on the other. Which is how it arrived.



I've ordered a short length of 12m id fuel hose and hopefully the damper has the 12mm fitting too, otherwise we go again.  ::)
'77 280se

SteveDuNord

#100
Managed to get the new pump on using the existing fuel hose (new hose was too small for the damper, absolute pita).

It's dark, I'm late for dinner, managed to get everything to stop leaking and guess what? One of the electrical connecter threads snapped.



Just like the front shock absorber I recently tried to fit. Snapped bolt - leaving me sh*t out of luck. I hate this car!!

Here's the old pump. I'm praying that if I remove the blue plastic I'll see that the threads can be removed so I can add it to the new pump. Short of that, I could solder the lead to the pump, but have no appetite to solder near fuel.



'77 280se

SteveDuNord

Has it really been 9 months since I last started this car?

Well, having wasted money on a new Bosch fuel pump (see above), I finally got around to fitting my cheapo ebay pump. Didn't bother jacking her up, and everything went swimmingly. Fired right up!

Performed the fuel return test this morning and voila - heading towards a litre after maybe 15 seconds.  8) So it was definitely worth changing the pump.



I felt sure that the pressure test would now show perfectly normal readings, and that all my warm start issues would be behind me.

Nope.  >:(

Still getting 5.1 bar on system and control pressures (valve open/valve closed). No difference whether WUR is connected or unplugged. Fuel cap on or off.

Having already serviced the WUR, and changed the FD fuel inlet filter, I am at a loss as to what my issue is. Damper is functioning as normal according to gauge.

Anyone?

'77 280se

raueda1

Quote from: SteveDuNord on 19 June 2023, 06:27 AMHas it really been 9 months since I last started this car?

Well, having wasted money on a new Bosch fuel pump (see above), I finally got around to fitting my cheapo ebay pump. Didn't bother jacking her up, and everything went swimmingly. Fired right up!

Performed the fuel return test this morning and voila - heading towards a litre after maybe 15 seconds.  8) So it was definitely worth changing the pump.



I felt sure that the pressure test would now show perfectly normal readings, and that all my warm start issues would be behind me.

Nope.  >:(

Still getting 5.1 bar on system and control pressures (valve open/valve closed). No difference whether WUR is connected or unplugged. Fuel cap on or off.

Having already serviced the WUR, and changed the FD fuel inlet filter, I am at a loss as to what my issue is. Damper is functioning as normal according to gauge.

Anyone?
Huh, I responded earleir but it somehow didn't post.  Not the first time that this has happened to me, maybe it timed out.  Anyway,  First, are you absolutely sure that the fuel return line is clear?  If not check that first. It needs to b e REALLY clear.  Just being able to blow high pressure air through may deceive you, it can be occluded enough to mess up the return flow. Disintegration of the hose between the steel line and tank is a known issue.

Failing that, our colleague Feather535 recently suffered from a very similar problem, as have I.  It took a long and circuitous road to getting solved but he did and is now happily working on new problems.  Anyway, I suggest finding his threads (there may be a couple) and carefully following beginning to end.  At a minimum some of the key CIS troubleshooting issues will be revealed.  At least you'll come away with some ideas.  Cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

SteveDuNord

Quote from: raueda1 on 20 June 2023, 08:07 AMHuh, I responded earleir but it somehow didn't post.  Not the first time that this has happened to me, maybe it timed out.  Anyway,  First, are you absolutely sure that the fuel return line is clear?  If not check that first. It needs to b e REALLY clear.  Just being able to blow high pressure air through may deceive you, it can be occluded enough to mess up the return flow. Disintegration of the hose between the steel line and tank is a known issue.

Failing that, our colleague Feather535 recently suffered from a very similar problem, as have I.  It took a long and circuitous road to getting solved but he did and is now happily working on new problems.  Anyway, I suggest finding his threads (there may be a couple) and carefully following beginning to end.  At a minimum some of the key CIS troubleshooting issues will be revealed.  At least you'll come away with some ideas.  Cheers,

Thanks. I'll take a look.

Just so we're on the same page here: all I've established is that the return flow was low (measured from the FD), but a new pump has solved that problem.

Are you suggesting checking the flow actually gets all the way back to the tank, with no blockage? I wouldn't know where to start and have no high pressure air source to perform that kind of test. I'll have to look into it.

Would a partially constricted return flow affect cold start control pressure?

I was leaning towards a busted/blocked WUR...
'77 280se

raueda1

Quote from: SteveDuNord on 20 June 2023, 12:22 PM
Quote from: raueda1 on 20 June 2023, 08:07 AMHuh, I responded earleir but it somehow didn't post.  Not the first time that this has happened to me, maybe it timed out.  Anyway,  First, are you absolutely sure that the fuel return line is clear?  If not check that first. It needs to b e REALLY clear.  Just being able to blow high pressure air through may deceive you, it can be occluded enough to mess up the return flow. Disintegration of the hose between the steel line and tank is a known issue.

Failing that, our colleague Feather535 recently suffered from a very similar problem, as have I.  It took a long and circuitous road to getting solved but he did and is now happily working on new problems.  Anyway, I suggest finding his threads (there may be a couple) and carefully following beginning to end.  At a minimum some of the key CIS troubleshooting issues will be revealed.  At least you'll come away with some ideas.  Cheers,

Thanks. I'll take a look.

Just so we're on the same page here: all I've established is that the return flow was low (measured from the FD), but a new pump has solved that problem.

Are you suggesting checking the flow actually gets all the way back to the tank, with no blockage? I wouldn't know where to start and have no high pressure air source to perform that kind of test. I'll have to look into it.

Would a partially constricted return flow affect cold start control pressure?

I was leaning towards a busted/blocked WUR...
Exactly.  If fuel return in blocked or restricted too much then [system pressure] = [control pressure].  So check this first before going down the WUR rabbit hole.  Blowing compressed air through the return is just one way. You can try just blowing through the return tube but that's very hard to do and you need to blow out the fuel in the line before hearing bubbles in the tank.

Here's another way:  disconnect the fuel return line from FD.  Hook up a tube out of the FD into a container, similar to the fuel flow test.  Run fuel pump and check pressures.  If the fuel return is blocked AND the WUR is actually OK then your control pressure should now be ok cause you removed the cause of the back pressure against the system.  Hope that makes sense.  There's no guarentee that this will solve the problem, but it's easy.  And if fuel return is constricted then there's no hope of ever getting the rest right.  So give it a shot.  good luck and cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0