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Electronic Fuel Pump '64 220s

1K views 3 replies 3 participants last post by  Adara 
#1 ·
Well year two is here for figuring my project out, had about six problems from last year to work on...

- Took an air filter box off a 1968 250, couldn't get a filter for it... just got a K&N E-3780 for $65, pricey, but I won't ever need to look for another one... still need the studs though...

Anyone know the size of the thread for the studs in zenith carbs?

- Master Cylinder was shot, I went to Ace and shaped some rubber washers with a dremel that seem to have held quite well, I marked the fluid level and it hasn't changed from last year, but knowing that $1.50 in parts is all thats standing in the way of a $300 booster getting wrecked is enough make me want a new master cylinder (cheapest I can find is $170ish).

- Power steering only worked to the right... amazingly enough after I flushed the fluid and replaced the pump gaskets last year it still did not work to the left... this year is does... so I guess new fluid and time fixed that for me...

- Horn honks when turning, last year the solution was pull the fuse... but I like having wipers and the horn is cool... luckily there is currently a thread going on about the horn problem so that will hopefully be resolved there...

- So the last problem is the idle (dual carbs are kicking my a$$) two people I've had look at it believe the problem lies in fuel pressure not the carbs themselves.

So what pressure should a 1964 220S with dual zenith carbs have?
Would I have better luck with an electronic fuel pump instead of the mechanical one?
Could an electronic fuel pump be installed while leaving the mechanical pump intact (I'd like to keep it as original as possible)?
 
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#3 · (Edited)
Mechanical pump on the engine was replaced 5 years ago (I didn't do it, I have receipt and it looks fairly new). I rebuilt the carbs last year because one was leaking gas. before the carb rebuild it wouldn't even drive, now it shifts pretty good and will "do 80(mph)" (some "Mercedes guy" around here asked if it would, so I tried) so I think the carbs are working right, it just won't idle...

If I knew what pressure to look for it might be a good start... and how to test the pressure come to think of it...

edit:
Come to think of it I don't remember a return line coming off the carbs when I took them off. there was just gas line connected to the front carb and then a gas line from the front carb to the back carb... is the return line somewhere else?
 
#4 ·
An electrically powered fuel pump in an electronic return less fuel delivery system for an internal combustion engine is controlled during transient engine operating conditions. A controller senses an operating parameter to infer whether a transient engine operating condition exists. Then, the controller generates an estimate of a fuel pump correction signal based on this inference. The correction signal is generally sufficient to cause the fuel pump to respond to the transient condition, by supplying a generally correct amount of fuel, prior to the engine requiring a change in fuel quantity.
 
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