300SE fuel pump - PeachParts Mercedes-Benz Forum

DrB300SE · #1 06-22-2011, 01:32 PM

changing the fuel pump on my 89 300 SE. any precautionary DIY suggestions? I can't drive the car to lower the fuel level, and I don't have the "special clamps" for the lines. To siphon the gas would require "the old fashioned way..." thanks for any help and suggestions.

tbomachines · #2 06-22-2011, 01:42 PM

http://www.harborfreight.com/multi-use-transfer-pump-66418.html

Just an idea - if you don't want to get a mouthful of gasoline one of these should do. Some MBs have baffles in the filler neck though

Hit Man X · #3 06-22-2011, 02:01 PM

Did the one on my 300SEL with half a tank, just change the supply line quickly and you will lose maybe a few liters.

DrB300SE · #4 06-22-2011, 02:02 PM

thanks. Think I'll run down to the local auto store. Not sure about the baffles, but for $6 worth a try.

Hit Man X · #5 06-22-2011, 03:35 PM

That hand pump will last about one use, they are very poorly made.

DrB300SE · #6 06-22-2011, 06:31 PM

pulled the old pump fuel line, put the new one right on. Minimal loss of fuel. Still doesn't run though. Starts after pumping the gas pedal but doesn't continue to run. Was running fine last week. Went out to make one last errand run before going out of town...and nothing. Turned over, just didn't fire up. Have replaced the fuel filter and pump. Each step takes it a bit closer. Just glad this didn't happen in old town Savannah last week!!

mak · #7 06-22-2011, 09:56 PM

Squirt a little car cleaner into the air intake ,it should fire up for a few seconds if the ignition system is operational . An old Fuel pump relay may be in operative, they do cause all sorts of running and stalling faults.

300se /89

DrB300SE · #8 06-24-2011, 12:25 PM

Starts with starting fluid. Jumped the fuel pump relay this morning...no start. Any suggestions? Getting tired walking to the store..beer is heavy! Might still be contaminated fuel?

tbomachines · #9 06-24-2011, 01:20 PM

If the FPR was bad then the pump wouldn't turn at all with the ignition on. Have you checked your OVP fuse?

DrB300SE · #10 06-24-2011, 02:13 PM

the 10 amp fuse, clear top box on the firewall?

tbomachines · #11 06-24-2011, 02:41 PM

Yep, check to make sure the fuse is ok, if good, then if you have a spare OVP swap it and see if it checks out. Thats the easy stuff, beyond that you're getting into more difficult troubleshooting with the Bosch injection system unfortunately (and out of the area of my current experience)--I would imagine the first test would be fuel pressure.

tbomachines · #12 06-24-2011, 02:43 PM

Also, you might want to edit your profile and add a general location, and also your year/model in the signature, just so its a quick reference. Perhaps there are some local members who would be willing to help out?

DrB300SE · #13 06-24-2011, 02:48 PM

does the fuse just pull out? seems to be stubborn. what does the ovp do?

tbomachines · #14 06-24-2011, 02:55 PM

It should, however if its not visibly blown/burned then I wouldn't worry about yanking it out. The OVP is the over voltage protection relay and it controls a number of variables on the car. Its a common failure item, usually causes stalling out, hard starts, and can lead the car to be inoperable. The solder joints on the relay itself tend to get tiny cracks and can potentially be reflowed with new solder but most folks just pop in a new OVP. Here are a bunch of links that will probably be quite useful:

OVP relay, Over Voltage Protection Links

You can find this and a lot of other DIY resources at the top of the page--hover over "Resources" and then under that click "DIY links". They cover just about anything and everything MB related.

DrB300SE · #15 06-24-2011, 03:07 PM

thanks. Visually the fuse looked good.