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Help, fuel issue

Started by rumb, 21 February 2024, 02:03 PM

rumb

So I have the new fuel pump in. 
I dont get any voltage at pump in key position 1 or 2.
I've jumpered the relay and no change. I have voltage on pin 1 - upper left one. (jumped upper left pin to second one down on right side.)

If I pour gas in throttle the car runs until that fuel runs out.

If I apply 12v directly to pump it runs, but engine will not run.
The intake plate has resistance.

Is there something I messed up with all the distributor harness wires I rebuilt?

Any troubleshooting ideas?


'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

Max-NL

Just checked the diagnostic part of the fuel pump relay on the Handbook for the M117 with the M100 (I have that only in German), and they are identical. Perhaps This would be a good place to start diagnosing?

https://handbook.w116.org/cd/Engine/107/M117_45/073-165.pdf
1971 R107 350 SL
1972 W108 280 SEL 3.5
1975 W116 280 S
1975 W116 450 SEL 6.9 #140
1977 W123 230
1992 W124 230 CE
2001 Ducati Monster S4

daantjie

Maybe check the blue safety plug and wiring on the fuel distributor?
Daniel
1977 450 SEL 6.9 - Astralsilber

rumb

Thanks, will be working thru that doc.  That was exactly what I was looking for.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

rumb

Went thru diagnosis chart and everything passed, but still no volt at pump,  Went looking for trunk branch wire harness connector and saw the ground point that is behind passenger seats on right side and the brown wire bundle was just loosely attached.  Tightened up nut and bolt and car started.  ;D

Copious smoke, Im hoping just because it sat so long and I porbably dumped a lot of fuel in the intake.  Will run more later to see it it clears up when the engine gets warm.

Also even though I added a couple gallons of fresh fuel, what comes out is still yellow, though not as stinky as just the old gas was.  I guess 6 year old gas doesnt burn that great. :o
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

daantjie

Nice 8)
Yup I've found that that 6.9 hunk of metal takes a LONG time to fully warm up.  Helps too if your cooling system is working properly which I'm sure yours is.
Daniel
1977 450 SEL 6.9 - Astralsilber

raueda1

How much of an engine rebuild did you do?  Rings, piston hone, anything like that?  Can't recall now...  And how much old gas do you think is mixed with the new?  And how long did you run it?  So many questions!  But at last it's running!  You're in the home stretch.  Cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

rumb

All well.... fired up next day and idled just fine.

Draining rad for 3rd of 4th time now this time to install new radiator overflow hose. Found one MB made after they transitioned the overflow tank to have a larger outet,  It has one end larger to fit!

Also need to remove lower radiator hose for access to drill hole in frame and install rivnut to hold the Fanfare Horn mounting bar. The hole on the other end uses the mounting for the oil tank hose guard.  Pictures soon....
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

raueda1

Quote from: rumb on 27 February 2024, 02:50 PMAll well.... fired up next day and idled just fine.

Draining rad for 3rd of 4th time now this time to install new radiator overflow hose. Found one MB made after they transitioned the overflow tank to have a larger outet,  It has one end larger to fit!

Also need to remove lower radiator hose for access to drill hole in frame and install rivnut to hold the Fanfare Horn mounting bar. The hole on the other end uses the mounting for the oil tank hose guard.  Pictures soon....
That's great news, and certainly a big relief.  Because......  you just never know.  My car did the same after rebuild, basically 1 blue puff and that was it.  I had to fiddle with idle adjustments a little but that was it.  Cheers
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0