420SEL cold start problems
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Newbie
Joined: Mar 2018
Posts: 3
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2011 Mercedes-Benz E550
420SEL cold start problems
Hi everyone, new here. After giving up 190e 2.6, a year later I decided to buy 1987 420sel. Car didn't run right when I was buying it in cold weather, but it did fire up after cranking a few times and holding gas pedal. Then I drove it home 600 miles and parked inside garage for two weeks and then started tackling cold start issue(it actually didn't fire up after few cranks). Seems like cold start valve doesn't get voltage when started is operated. Here's what I've done so far: from fuel pump relay cold start wiring continuity seems okay, replaced coolant temp sensor(green two prong, has around 12 k ohms at current cold temp) and checked wiring continuity also seems okay. Bought refurbished fuel pump relay, that didn't help either. After cranking, if I loosen fuel line at cold start valve, fuel starts spraying. Now here's a list of parts that I've bought with intent of getting it running right: two fuel pumps, fuel accumulator, fuel filter, spark plugs and wires. Anyone has any advice on proper troubleshooting procedure, or should I replace fuel pumps, filter and accumulator before anything else?
Senior Member
Joined: Apr 2007
Posts: 351
Likes: 90
Take it to someone who knows how the system works and quit shooting from the hip with parts. The cold start valve only sprays during cranking and only several squirts. The issue was there when you bought it so it was likely an issue before you bought it and who knows what has been 'tinkered' with. Probably should have kept the 190E. If the tamper plug was removed from the adjustment tower by the fuel distributor then it could be anyone's guess. It's the first place 'mechanics' start to tinker.
