This is a really old thread... but hey, I used the SEARCH and this is what I got.

I have an 86 230E W124 with the M102 engine.

Last night -- no start. I pulled the Fuel Pump Relay and jumped pins 30 and 87. It still wouldn't start.

I jumped pins 30 and 87V. Started. Ran normally and got me home.

This is similar to Ron Johnstone's experience.

BTW, I jumped the pins on the relay itself, and plugged the relay back in its socket. With the jumper between 30 and 87, I got all the warning lights on the dash lit up, but the key was on OFF. It still won't start.

With the jumper between 30 and 87V, I hear some clicking noises in the relay box area -- and the car would start and run normally.

Thanks to this board, I learned to carry a piece of 'jumper wire' in my ashtray just for failures like this.

My Fuel Pump Relay is probably similar to that used on the 190E's.
Part #001 545 90 05
Says "Kaltart Steuerung"
Has pins 30, 15, 87, 50, TD, 30, 87V and TE.

Should I have just jumped 30 and 87 and left the FPR off?

I'm thinking of building my own Fuel Pump Relay -- has someone done this before? Schematics would be nice.

Thanks in advance,

Johan Limcangco
Manila, Philippines
79 350SE
86 230E
http://www.geocities.com/johan01.geo
johan01.geo@yahoo.com

Glad you're able to run with the jumper. If you carefully examine your board you'll probably find a bad solder connection, which is easily fixed if you know your way around electronics. I carry a spare relay with me now for these annoying problems. Apparently any relays that have the same pin configuration will operate in the car, even though they have different part numbers, so a similar spare from a wreck - if it works, will get you home.

__________________
'76 240D-Sold
'78 240D-Sold
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet- under restoration
'86 560SL 124K Miles-Sold
'94 320E Wagon, 74K Miles-128K Miles JUNKED
'06 E350 Wagon, 84K Miles
07 SL550, 14K Miles

I opened the relay and inspected the insides of the relay. No cracked solder however, it did have lots of grime and green stuff near the solder connecting the socket pins.

There are two relays mounted on the board, and they're the same size.

With my trusty RS Multimeter, I found these:
1. Between Pins 30 and 87, 61.8 ohms.. with the 1st relay pushed down, its 0 ohms.

2. Between pins 30 and 87V, its infinite ohms... with the 2nd relay pushed down, its .71 ohms.

Two things come to mind:
1. The green powdery stuff on the board is making funny electricity (sorry, I made that up).

2. The 2nd relay has bad contacts... note, my car started with pins 30 and 87V shorted, so this faulty component inside the Fuel Pump Relay blackbox is WHY the relay doesn't power up the fuel pump.

I also checked my German to English dictionary, and "Kaltart Steuerung" literally translates to "Cold Start Controller". So I'm guessing here that this particular box's main function is to control the Cold Start Injector --- so I deduce pins 30 and 87 activate it. And 30 and 87V is the secondary function, which powers the fuel pump.

Did I get it right?

Your inputs would be great. Thanks again!

Johan Limcangco
Manila, Philippines
79 350SE
86 230E
http://www.geocities.com/johan01.geo
johan01.geo@yahoo.com

I must have made a mistake somewhere....

I removed the fuel pump relay from its socket and stuck the jumper wire directly at the holes corresponding to pin 30 and 87 on the FPR... this made the fuel pump run -- and the engine was started normally.

* I don't know why the car ran when I jumped 30 and 87V and put the FPR back in its socket. *

If I connect pins 15 and 31 of the Fuel Pump Relay directly to the battery's 12V, the FRP would close the connections between 30 and 87 momentarily.

With the key on, I get a volt-meter and check the output of the socket corresponding to 15 and 31 on the FPR and I only get 9 volts. 9 volts. I was expecting to see somewhere around 12 volts here. Is this correct?

My Fuel Pump Relay may be ok after all, and I just have low voltage at the trigger side of the relay. The witchhunt continues.

regards,

Johan Limcangco
Manila, Philippines
79 350SE
86 230E
http://www.geocities.com/johan01.geo
johan01.geo@yahoo.com

I'd advise a thorough scrubbing of your pc board with an appropriate electronic parts cleaner and brush so that you can better inspect the contacts.

__________________
'76 240D-Sold
'78 240D-Sold
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet- under restoration
'86 560SL 124K Miles-Sold
'94 320E Wagon, 74K Miles-128K Miles JUNKED
'06 E350 Wagon, 84K Miles
07 SL550, 14K Miles

I opened up the Fuel Pump Relay and gave the PCB a good cleaning with an old toothbrush and a mild acid. One of the "legs" connecting the pins on the base of the relay and the PCB has crack. Several solder points did not look shiny.

With a soldering iron, I removed the old solder and applied fresh lead. I soldered an internal jumper wire from the base of the pin to the PCB to 'fix' the cracked leg.

Put it back together and plugged it in -- the car started.
So far, so good. We'll see if this 'fix' really 'fixed' it.

Although, I'm still concerned that the sockets corresponding to pins 15 and 31 only showed 9 volts instead of 12 volts.

Johan Limcangco
Manila, Philippines
79 350SE
86 230E
http://www.geocities.com/johan01.geo
johan01.geo@yahoo.com

Hopefully this re-soldering will cure your problem. Did you neutralize the acid that you used on the board by throughly spraying the board with a electronic "tuner cleaner"? Available from Radio Shack or any good electronics supplier. As you have a serious humidity problem, I'd give the board a protective spray with something like clear Krylon, but shield the working relay contacts when you do. Good luck!

__________________
'76 240D-Sold
'78 240D-Sold
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet- under restoration
'86 560SL 124K Miles-Sold
'94 320E Wagon, 74K Miles-128K Miles JUNKED
'06 E350 Wagon, 84K Miles
07 SL550, 14K Miles

Hey I'm looking at a 300e soon and I think it has a bad fuel pump relay, so I was wondering: How exactly do you short the 30 and 87 pin and what does it mean to short them?
PS Sorry in advance for noobie question

Use a length of wire attached at each end to the pins, so that you create a circuit directly from one pin to the other. In other words, you're creating a "short" circuit between them.

__________________
1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't

Hello

I have a 1987 300E car won't start. I've owned the car since 2001 the fuel pumps may be original.

About 5 years ago the fuel pump relay went bad and I replaced it, around the same time I changed the fuel filter.

Now car won't start. I removed the fuel pump relay and jumpered 30 and 87 with my Fluke meter in Amps setting and see that the fuel pumps are drawing 7 Amps. However I don't hear them buzzing. Its 10pm and I am doing this outside on the street my car is parked at the sidewalk curb infront of my home. Shouldn't I hear the pumps buzzing? I had VW rabbits with CIS in the 80s they had a similar fuel pump and I recall I could hear the pumps buzzing.

so after my post I went back out to troubleshoot the car.

I unscrewed the fuel line to the # 1 injector then went inside the car and cranked the engine over. No fuel coming out of the fuel line.

I then removed the fuel pump relay and jumped it, this time I could hear the pump buzzing however no fuel coming out of the fuel line.



what should I check next? Fuel going to the fuel distributor? I recall the VW CIS had a warm up pressure regulator and the 300E should have similar, that would increase the fuel pressure when the car was cold, perhaps this is bad?

What would be the next steps? Could a massive vacuum leak cause this? I was always suspect of the idle air hoses?

this morning I removed the air cleaner and then unscrewed the fuel supply line to the fuel distributor, put a rag over it and then cranked the engine over for a couple of seconds and then check the rag. It had a good amount of gas on it.

I reattached the fuel line and then removed the two connectors, front and back that connected to the fuel distributor, I also removed a similar one that was in front of the front one. I sprayed Deoxit on both ends of the connectors and took a small metal brush to the male pins. Reattached and the car started right up!!!!!