Did I blow a Fuel Pump?

While changing my fuel filter, and the 2 copper "o" rings replaced with it, I noticed the lower fuel pump, outer "o"ring was also leaking (92 190e 2.6) takes 3 copper "o"rings.
Removed outer bolt tightened inner sleeve bolt to compress center o ring, then new copper o ring and install outer bolt, tighten slowly, release C clamps on fuel lines......look for leaks no leaks. Reconnect battery, start engine...let idle....look for leaks. Small drops slowly forming, fuel pump outer o ring bolt....using socket wrench...tighten bolt a little more, almost there, use open wrench to hold fuel pump for last little bit. The moment the open wrench touched fuel pump, the engine stopped. I know, forgot gas cap (pressure). Turn over strongly, try to start, and die. 20 times. It was like someone shut off the key. checked fuses, over voltage relay, fuses look good ........please help..Rick
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If it was running and you shorted the + connecter to the wrench..... you fried your fuel pump relay. It is NOT fused!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Fuel filter reversed? Fuel pump is a roller vane type,did you squeeze it too tightly?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
No, fuel filter properly installed. I didn't squeeze fuel pump, I was holding 2 pump/ accumulator frame as I was tightening fuel pump cap nut, a o ring. Fuel pump connectors have rubber L shaped boots on them, now found to be badly cracked. I Don't see fuel pump relay on list of parts for 1992 190E 2.6 . Goes from 190E 2.3 '87 to '93 190E 2.3-16 all....190E2.6 to '89 MAS control unit 190E 2.6 from '90 425.00 I'm screwed!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sounds like you have. I've done it and seen it done a few times over the years. For some reason the fuel pump doesn't like to be touched when it's working (like most of the office girls, ha ha). ALWAYS turn the engine off when tightening the fuel pump.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Augh! I told you about the aviation form-a-gasket... the only way to solve that leaky problem... Seems like you may have zapped the fuel pump relay. Replace the fuel pump fuse... don't just look at it.
If you have service manual... it will tell you what pins you have to jump to test the fuel pump... once jumped... start engine... if keeps running, then it is fuel pump relay.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I only have a chassis manual and a Haynes Benz 2.3 '85 to '88 most parts apply. I Now find major changes were made in the 201 series 1989 to '93 end of series. (tragedy really focuses your attention) Stupid, to put a wrench on fuel pump without Redisconnecting battery. Is there a way to check out fuel pump operation before commiting to replace MAS relay. No fuel pump relay here. (just bought aviation form-a-gasket) whimper, sigh......Public library has 103 engine manual, and at least 40 Mercedes, and Bosch manuals
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You can buy rebuilt MAS relay... instead of the full price at dealer... go to mbcoupes.com and look under part supplier list for electronic rebuild... I'll check for pins tonite...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Check http://www.mr-auto-parts.com
It shows you do have fuel pump relay... MAS is for like air conditioner stuff...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
MAS means Motor Aggregate System. MB combined the klima relay and fuel pump relay into one unit.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tiger schrieb:

Normally it should be battery 30 to 87. Of course you can test the pump dirctly using a 3 m cable to battery dirctly.
--

Roland Franzius

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I remember having to remove this MAS to shut off fuel flow when I did a compression check. Black, 3x6 inch rectangular relay behind battery, with a knob on top you turn to make it pull itself down and seat. I forget now but it combines several functions into one relay.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Went to Archives: Electrical troubleshooting manual N16 Engine control systems,.....After 1990 these relays went solid state, combined into MAS ..... fuel pump relay, air injection pump relay, transmission control points relay, A/C compressor relay, heater for O2 sensor, and some engine controls, But only in 2.6 201 series, 2.3 no change!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.