Fuel Pump Relay Repair on 190E 2.3 - Benzworld.org

tigerpaw · 08-15-2005, 06:43 PM

Is it "usually" possible to repair a fuel pump relay? What are the most likely things that makes them not function properly, or not at all. If it's usually something simple, like soldered joints that come loose, I would prefer to take it apart and fix. By the way, any suggestions on how to best get it apart (looks like it's "sealed-up" at the factory with some type "glue".

spanners · 08-16-2005, 01:10 PM

In most cases, it is as simple as dry or cracked soldered joints that can be fixed a soldering iron.

On the underside where the pins are, there is a clear sealer around the outside.

Scrape that off and use a screwdriver to prize the outer casing off.

The circuit board then slides out.

tigerpaw · 08-21-2005, 07:59 PM

Thanks for the reply. It was easy to get the circuit board out, but I did not find any loose joints. Everything seemed OK.
While the cover/housing was off, I temporarily re-installed it so I could observe the relay contact's working. As before, the relay contact usually held in, but a couple of times it disengaged when it should not, and the engine stalled.
Is there some other sensor (engine vacuum??, oil pressure??) that sends a signal that the engine is running that keeps this relay contact engaged? Because if there is a "false" signal that the engine is not running, then the relay would release, thereby stopping the fuel pump (would not want it to keep running during an accident). Maybe my problem is not the fuel pump relay, but rather a sensor that is sporadically failing?? Any suggestions??

pika · 08-22-2005, 11:03 PM

Hello, I'm not trying to take over your thread, but Can u answer a brief question?
How the hell do ya remove the fuel pump relay completely !!
I'm trying to do a compression test and I need to disable the fuel.
I can get the black cover off, but I cant see how to remove the entire assembly.
Any help much appreciated !![8D]

spanners · 08-23-2005, 02:43 PM

The fuel pump relay itself is the most common fault.

It could be getting a signal from the ECU cutting it out, but this could be for any number of reasons.

Bad ECU
Bad crankshaft pulley sensor
Bad ignition pack

The list goes on.

If it is not the relay itself, I would suggest paying a garage to diagnose it to save you replacing loads of parts in the hope one will cure it.

spanners · 08-23-2005, 02:48 PM

pika

It should all come out as one unit. The fact your outer casing has split suggest somebody has opened the relay up to repait it at some point.

Pursueding it with a screw driver gently may get it out.

pika · 08-23-2005, 09:15 PM

Thanx Spanners !!

tigerpaw · 08-24-2005, 07:25 PM

Spanners, thanks again. I'm becoming more suspucious that in my case it's not the relay itself, but rather a sensor that sends a signal to the relay. Do you have a wiring diagram that would help me see what sensors are communicating with the relay?

tigerpaw · 08-24-2005, 07:35 PM

Pika, mine came out without the cover coming off. The "sealant" was still in place indicating it had never been taken off before. Once the cover has been removed, it probably would come off easier the 2nd time. Eventually it would likely come off before the pins come out of their sockets, as in your case. Be careful prying it out. Good luck.

spanners · 08-25-2005, 03:47 AM

Sorry, I don't have a wiring diagram. Try searching this forum, there may have been one posted previously, or start a new thread titled Wiring Diagram and someone mey have one.