I've recently bought a 300 sel 6.3 liter (euro specs)It,s using too much fuel,about 2 mpg! There is lots of black smoke. I.ve disconnected all the cold start devices but to no avail.Does anyone have any tips on setting-up the fuel injection on these cars.
Many thanks
Peter.

This car should get about 8-9mpg. No black smoke if tuned correctly. There is a spec on all of the little rods that controll the fuel injection pump. They need to be right. Trust this to only the best of techs.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I'm definitely with Benzmac on that one! That injection pump is a real bear. Hope it never goes out on you because Mercedes will hit you for...are you sitting down?.....$15,000 for a new one. In most cases the pumps can be rebuilt, but if not, woahh!! I believe the injectors are in the $700 neighborhood (that's for each one). Anyhow, you might want to send Neil Dubey an e-mail at 300sel63@aol.com and ask him how to go about properly diagnosing your problem. Neil is the 600, 6.3 and 6.9 master. His business is Star Motors in Endicott, NY. They only service those beasts, nothing else.



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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'89 420SEL
'93 300E 2.8
'72 Alfa Romeo 2000GTV
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12

With the fuel consumption that high, either the rack inside the pump is jammed or the cold start valves are leaking into the manifold. Check the fuel pressure. I've seen the wrong type fuel delivery pump used on these to save a few bucks cause massive cold start valve leaks.The cold start valves will open by themselves at 18-20 psi.
Other than that the best approach would be to pull the injection pump, injectors and cold start valves....then send them out to be tested/rebuilt before the excess fuel causes engine wear. You really don't want to let the car run for long like that.I had my injection pump done when my hiway fuel mileage dropped to 8 mpg. Now I get 15 to 16 mpg from it on the road.
Regards,
Randy D.

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W.R.Durrance
ASE Master Tech
Mercedes Tech 20 Years
68 250SE
68 SAAB 96 Ice Racer
69 300SEL 6.3
70 300SEL 3.5
81 300TDT

WOW! I have to admit that I'm still a novice at this internet stuff. Less than 24 hrs and you guys have responded so quick! To anyone that posts a reply to my fuel injection problem I'll by a beer or 2.Only problem is that you'll need to be in London to hold me to that promise!!!
Many thanks in anticipation.
Peter.

quote:

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Originally posted by nutsonmercs:
I've recently bought a 300 sel 6.3 liter (euro specs)It,s using too much fuel,about 2 mpg! There is lots of black smoke. I.ve disconnected all the cold start devices but to no avail.Does anyone have any tips on setting-up the fuel injection on these cars.
Many thanks
Peter.

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The most common problem with over rich mech injected motors is the inj pump thermostat (not the solenoid). The way to diagnose this problem is to warm up motor and pinch off the aux air that feeds idle during warm-up. I haven't done it in years on 6.3s but the idea is that as the t-stat warms up the airslide and the enrichment close at the same time. When warm shuting off the air line shouldn't drop the idle speed. This final shut-off can be adjusted at the t-stat but the t-stat has probably lost its umph (sp?).



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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician