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#1
Mechanicals / Re: Abrupt K-jet wierdness and...
Last post by raueda1 - Today at 12:12 PM
Thanks gents, helpful indeed.  Oddly, the car actually seemed to be running lean, i.e., rpms go up when metering plate is depressed.  I think that means too lean. :o   But pressure is so high I'm not really sure what rules even apply.  I'm going back through all the manuals, diagrams, postings etc - it's unnerving, cause I've done it all before, but over time I've forgotten details and there's a lot to forget!

Anyway, as for fuel return blockage, that occurred to me too.  I tried the compressed air trick and fuel line does seem to be open.  But maybe just barely.  I'm not sure that it's entirely clear though, just cause I can hear some bubbling.  It took a long time and a lot of pressure to clear the fuel from the line before bubbling was audible. I wonder if the return can be open enough to let some air through but still be occluded enough to create sufficient back-pressure to cause problems?

So - I'm going to put a container on the return outlet so there's no back-pressure at all and see what that does to the pressures.  Will report back in due course....   Thanks again and cheers.
#2
Test Drive / Re: BAT article on W116
Last post by gurrier - Today at 01:29 AM
Always interested to know why retailers hide the registration numbers of vehicles on sale -there can
be nothing more in the Public Domain than the registration plate of a vehicle.

This car posted on flickr in 2018 is described as 1977 whereas one in advert is stated to be 1979-
both 450 - interesting to know if they are the same -otherwise there is a new entry in the register.


#3
Mechanicals / Re: Force close warm coolant t...
Last post by Jan S - Yesterday at 11:04 PM
Quote from: adamb on Yesterday at 04:45 PMThere should be no problem with temporarily disabling this valve/securing it in closed position. If the engine is running fine, doesn't overheat, warms up quickly then I'd say there's nothing to worry about. Longer term devote some hours to finding the source of the leaks.

For reference the main source of leak on mine was a 1-into-2 slide valve in the driver's door (rhd). All vacuum hoses and connections were fine. You'll need a vacuum pump. I use the Mini MityVac bought ages ago from USA.



Thanks!

What do you mean by a "1-into-2 slide valve"?

Yes, I need to tackle this vacuum problem later
#4
Mechanicals / Re: Abrupt K-jet wierdness and...
Last post by Jan S - Yesterday at 10:59 PM
Agree with daantjie's figures. And fuel flow at return to tank (after main pressure regulator) should be 1-1.5 liter per minute if I remember the spec correctly.

The pump curve - pressure as a function of flow shows diminishing flow as the pressure rises. I'm not sure what the "dead-head" pressure of the pump is, i.e. when the flow equals zero and the pressure is at max.

If the pressure is significantly higher than 5,5-6 bar the return to tank must be somehow restricted, maybe due to a pressure regulator that is not opening correctly ... or other things. And I'm not sure how the injectors' spray pattern are behaving at too high pressures.

I would test return to tank flow, and check if the return pipe is "open" with the help of compressed air.

#5
Mechanicals / Re: Abrupt K-jet wierdness and...
Last post by daantjie - Yesterday at 08:35 PM
Dave I am pretty sure system pressure is what the pump puts out as a baseline, should be 5.5 - 6.0 bar.  Fully warmed up you should see (from memory) between 3.0 and 3.4 bar measured between the FD and the WUR, depending on ambient temps.  I am guessing the exhaust gasses must be eye wateringly rich at the moment?
#6
Mechanicals / Re: Force close warm coolant t...
Last post by adamb - Yesterday at 04:45 PM
There should be no problem with temporarily disabling this valve/securing it in closed position. If the engine is running fine, doesn't overheat, warms up quickly then I'd say there's nothing to worry about. Longer term devote some hours to finding the source of the leaks.

For reference the main source of leak on mine was a 1-into-2 slide valve in the driver's door (rhd). All vacuum hoses and connections were fine. You'll need a vacuum pump. I use the Mini MityVac bought ages ago from USA.

#7
Test Drive / Re: BAT article on W116
Last post by gurrier - Yesterday at 04:25 PM

As we know you take descriptions of used cars with a pinch of salt.
Why would you spend 20,000 on an example and leave
an ill matching petrol tank flap in situ.   Is that black electrician's
tape that I see wrapped around the ill fitting grommet for the wiring for the rear driver's side door.
Would be interested to know the registration.  Interesting to watch the market.
#8
Test Drive / Re: BAT article on W116
Last post by Mick74 - Yesterday at 03:36 PM
I'm on a roll this evening. Let's see what price this achieves.

https://www.carandclassic.com/auctions/1980-mercedes-benz-450-se-4o7e24
#9
Test Drive / Re: BAT article on W116
Last post by Mick74 - Yesterday at 03:33 PM
#10
Test Drive / Re: BAT article on W116
Last post by Mick74 - Yesterday at 03:31 PM
Yes, and more seem to be popping up for sale. This one just appeared here in Ireland.
https://www.donedeal.ie/vintagecars-for-sale/1975-mercedes-w116-450-se-s-class-fully-restored/31494605