W124 Wont start

[warnockp]

Having problem with 1994 E200. W124 Model. 111 Engine.

Car wont start, there is no spark and fuel pump is not kicking in.
Fuel Pump Relay and OVP Relay are working fine.

Pin 85 on fuel pump relay sometime only gets 2.5 volts and wont come in.
Any help would be appreciated.

Computer would not communicate with ecu
Flash test showed up no Faults.

 

[television]

Having problem with 1994 E200. W124 Model. 111 Engine.

Car wont start, there is no spark and fuel pump is not kicking in.
Fuel Pump Relay and OVP Relay are working fine.

Pin 85 on fuel pump relay sometime only gets 2.5 volts and wont come in.
Any help would be appreciated.

Computer would not communicate with ecu
Flash test showed up no Faults.

On all MB 124 relays Pin 30 is the 12v in and 87 is the output.

malcolm

 

[robinsykes]

I have had the exact same problem with my '94 E220. Garage replaced the Crankshaft sensor and problem went away. Hope this helps

 

[warnockp]

sorry,

pin 85 is earth.
pin 86 needs twelve volts to operate relay and give output to pin 87.
pin 86 is only getting 2.5 volts.

I am getting a crank shaft sensor to see if problem goes. thanks for help.

 

[kid-jensen]

124 No-Start

Warnockp, did the crank sensor fix it?

 

[warnockp]

no joy with crank shaft sensor.
completely at a loss now.

i was told to check pressure management system, does that make sense to anyone.

 

[johnnycapone]

Had a similar prob with my fuel pump relay on a 1990 te. It would start ok cold, but when warm it refused to start. Hope this may be of help.
Regards
John

 

[C220GJS]

? Ignition switch ,if it is turning over, may be getting power to the starter but not to the ignition circuit , just a suggestion.
Geo.

 

[television]

You still have not said what voltage you have on pin 87 of the Over voltage relay.
On the fuel pump relay Pin 30 should have 12v and when working it goes to pin87 and that goes to the pump. pin 30 goes to terminal block C on engine
Malcolm

 

[warnockp]

Over voltage relay is working fine.

fuel pump relay has 12volts at pin 30 , but 0 Volts at pin 87. This is because it is getting no signal to pin 86 to pull in relay and switch to pin 87.

When you apply voltage direct to pin 86 it switches and pin 87 has 12 volts and operates the fuel pump.

 

[television]

Over voltage relay is working fine.

fuel pump relay has 12volts at pin 30 , but 0 Volts at pin 87. This is because it is getting no signal to pin 86 to pull in relay and switch to pin 87.

When you apply voltage direct to pin 86 it switches and pin 87 has 12 volts and operates the fuel pump.

There is no connection to pin 86, its internal for testing, you can do a lot of damage putting 12v here and there, its a semiconductor device.

Malcolm