W126 won't start
 

My 89 420sel will only start after a dozen or so attempts of pouring some gas directly into the carberator. Once it starts it runs fine. I can drive it, park it and restart it same day no problems. Let it sit for a day or two and the process starts all over again. I have located what I believe to be the fuel pumps and fuel filter (one larger cannister and two smaller ones side by side below) there is a plastic cover over all three and next to rear passenger side wheel.

How do I diagnose the problem with limited diagnostic tools? Would it be easier to replace certain items? Finally, I will be working underneath a parked car, Is there a trick to disassembling the filter and pumps w/o getting gas everywhere.

Guys have been great with help in the past. TIA

I think it has to do with the fact that there is a carberator on your 89 420SEL. You probably want to check up on that.

oops. :eek:

has MB ever offered a carb. V8? nope.

Mercedez with Carb??
 

Well i've never heard of that either.. Are you sure thats a mercedez engine in there or maybe someone replaced it with some other engine.. i've seen it done with jags.. 350 small black.. I dunno about that carb thing.. may have to do some research.. :rolleyes:

I have no idea what's under your hood, but I doubt it's a carb. Your car most likely has a Bosch fuel injection system. MB did not put carbs on these vehicles. You likely poured fuel down the AMM(air mass meter) as some call it. If that helped, you may very well have a fuel problem.

You're going to have to elevate the rear of the car to get any kind of sane access to the fuel filter/pump(s) close to the passenger side rear wheel unless you weight 40 lbs.

Here's a photo of a 300-SEL AMM. I "think" the 420 is similar enough for this to at least show what you most likely have. The photo might be expandable. Look at the gold disc. This is where you probably poured fuel.


http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1EQ0PTV2S1H112V785&year=1991&make=MB&model=300-SEL-006&category=B&part=Air+Mass+Meter

w126 won't start
 

try replcing the fuel pump accumulator located forward of the fuel filter.if this is bad it is costing your engine both pressure and volume(fuel) it would explain yr description of events.

According to one pro who used to hang out here, faulty accumulators are responsible for hot start problems. Here's the link. While the car mentioned is not the same as yours, a lot of similar fuel components were used on this car.


http://www.peachparts.com/shopforum/showthread.php?t=11465&highlight=accumulator